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1

Uraniferous Surficial Deposits.  

National Technical Information Service (NTIS)

As a result of the discovery of uranium in surficial deposits of Tertiary to Recent age, in Australia and Southern Africa, increasing attention is being paid to the location and understanding of the genesis of these deposits. The paper discusses the defin...

P. D. Toens B. B. Hambleton-Jones

1980-01-01

2

Geology and Recognition Criteria for Uraniferous Humate Deposits, Grants Uranium Region, New Mexico. Final Report.  

National Technical Information Service (NTIS)

The geology of the uraniferous humate uranium deposits of the Grants Uranium Region, northwestern New Mexico, is summarized. The most important conclusions of this study are enumerated. Although the geologic characteristics of the uraniferous humate depos...

S. S. Adams A. E. Saucier

1981-01-01

3

Geology and recognition criteria for uraniferous humate deposits, Grants Uranium Region, New Mexico. Final report  

Microsoft Academic Search

The geology of the uraniferous humate uranium deposits of the Grants Uranium Region, northwestern New Mexico, is summarized. The most important conclusions of this study are enumerated. Although the geologic characteristics of the uraniferous humate deposits of the Grants Uranium Region are obviously not common in the world, neither are they bizarre or coincidental. The source of the uranium in

S. S. Adams; A. E. Saucier

2009-01-01

4

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

5

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

Microsoft Academic Search

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

Crayton J. Yapp

1997-01-01

6

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

Microsoft Academic Search

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

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

2004-01-01

7

Impact of catchment degree on peat properties in peat deposits of eutrophic bog  

NASA Astrophysics Data System (ADS)

Fundamental works of many investigators show that according to the biophysical properties peat deposit (PD) is divided into 2 layers: active and inert. It is interesting to analyze the supposed changes in PD of eutrophic bog according to different data (physical, chemical and biological). The researches were carried out at two plots of one bog (points 1 and 2, positions 56° 21' NL, 84° 47' EL, Russia, Siberia). Agricultural afforestation (pine planting) was made at one of them (point 2) 60 years ago. Now this plot is absolutely identical in ground cover to 1 point, but other conditions are significantly changed. In spring bog water level is at the depth of 20cm at 2 point (at 1 point it is near water face), it lows up to 53 cm during summer time (at 1 point - up to 37 cm). According to redox conditions zone of anoxic-oxic conditions reaches meter depth at 2 points. PDs don't significantly differ in activity of ammonifiers but in activity of cellulose-lytic aerobic microflora it follows that it is more active at 2 point in PD active layer. In spite of good aeration, more favorable conditions were created also for anaerobic cellulose-fermenting microflora in PD of 2 point in comparison with 1 one. Activity analysis of denitrifying agents and microflora of other physiological groups also showed high activity of biota at the plot with afforestation amelioration. This fact was confirmed by high coefficient of mineralization. Time of drainage effect created by afforestation amelioration influenced group composition of peat organic matter which builds up PD of examined plots. According to fractional and group composition data fracture of hard-to-hydrolyze organic matters decreased during the process of microflora activating at the plot with afforestation amelioration but FA content increased. Fractional composition of nitrogen showed that content of mineral nitrogen compounds definitely increased. Thus, 60 years of surface drainage influenced composition change of peat organic matter along all PD profile. In our opinion, it is explained by rearrangement of qualitative and quantitative composition of microbic biota in consequence of alternate anoxic-oxic conditions creation along all PD of investigated eutrophic bog located in the dingle of ancient flow. Keywords: peat deposits, eutrophic bog, Siberia, microbiological processes, change of organic matter. Acknowledgements: This research was supported by RFFR (No.No. 09-05-00235, 09-05-99007), Minister of education and science (No. 02.740.11.0325).

Inisheva, L. I.; Golubina, O. A.; Rodikova, A. V.; Shinkeeva, N. A.; Bubina, A. B.

2010-05-01

8

Raised atmospheric CO2 levels and increased N deposition cause shifts in plant species composition and production in Sphagnum bogs  

Microsoft Academic Search

Part of the missing sink in the global CO2 budget has been attributed to the positive effects of CO2 fertilization and N deposition on carbon sequestration in Northern Hemisphere terrestrial ecosystems. The genus Sphagnum is one of the most important groups of plant species sequestrating carbon in temperate and northern bog ecosystems, because of the low decomposability of the dead

Frank Berendse; Nico Van Breemen; HAkan Rydin; Alexandre Buttler; Monique Heijmans; Marcel R. Hoosbeek; John A. Lee; Edward Mitchell; Timo Saarinen; Harri Vasander; Bo Wallen

2001-01-01

9

Early Effects of Atmospheric Ammonia Deposition on Calluna Vulgaris (L.) Hull Growing on an Ombrotrophic Peat Bog  

Microsoft Academic Search

This paper reports data from a field study investigating the impacts of elevated ammonia (NH3) deposition on Calluna vulgaris growing on an ombrotrophic peat bog in S.E. Scotland. Shoot extension, foliar N concentrations, chlorophyll concentration and chlorophyll fluorescence were measured during the second growing season of exposure to a gradient of ammonia concentrations. Results indicate that NH3 increases growth between

J. A. Carfrae; L. J. Sheppard; J. A. Raven; I. D. Leith; W. Stein; A. Crossley; M. Theobald

2004-01-01

10

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

Microsoft Academic Search

Bogs of Alberta, Canada are peatlands that are both Sphagnum-moss dominated and nutrient limited. Due to their ombrotrophic nature, nitrogen (N) is deposited only via atmospheric deposition (wet\\/dry) and biological N2 fixation. Historically, bogs of Alberta are unpolluted with low rates of atmospheric N deposition (15 kg ha-1 yr-1). Due to the extensive rich bitumen deposits under northern Alberta, however,

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

2010-01-01

11

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

12

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

PubMed

Peat cores taken from eight Swiss peatlands were used to calculate inventories of anthropogenic Pb using either Sc or Zr to quantify Pb derived from rock weathering. The shapes of the Pb/Sc and Pb/Zr profiles suggest that Pb was supplied exclusively by atmospheric deposition at all sites. At one of the sites (Etang de la Gruère), anthropogenic Pb was calculated using both Sc and Zr as the conservative reference element. Lithogenic Pb determined using Sc was twice that obtained using Zr, possibly because Zr resides only in zircons which are dense compared to pyroxene and amphibole which are the main Sc-bearing phases in the earth's crust. However, the inventory of 'natural' Pb (supplied almost entirely by soil dust) is dwarfed by the anthropogenic inventory such that anthropogenic Pb calculated using Sc and Zr agree to within 5%. The total amount of anthropogenic Pb accumulated in the bogs was calculated by simply adding the mass of anthropogenic Pb for each peat slice over the length of each core. Cumulative, anthropogenic Pb calculated in this way ranged from 1.0 to 9.7 g/m2 and showed pronounced regional differences: the site south of the Alps (Gola di Lago in Canton Ticino) with direct exposure to the heavily industrialized region of northern Italy received nearly 10 times more anthropogenic Pb as the sites in more remote alpine regions (Schöpfenwaldmoor in Canton Berne, and Mauntschas in Canton Grisons). The approach used here to calculate cumulative, anthropogenic, atmospheric Pb (CAAPb) is simple and robust, independent of the chronology of Pb deposition, and makes no assumptions about the immobility of Pb within the peat profile. Given the worldwide distribution of peat bogs, it should be possible to undertake continental and global inventories of atmospheric metal deposition, for both the natural and anthropogenic components of most trace metals of environmental interest. PMID:10813459

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

2000-04-17

13

Mid and late Holocene dust deposition in western Europe: the Misten peat bog (Hautes Fagnes - Belgium)  

NASA Astrophysics Data System (ADS)

Dust deposition in southern Belgium is estimated from the geochemical signature of an ombrotrophic peatland. The Rare Earth Elements (REE) and lithogenic elements concentrations, as well as Nd isotopes, were determined by HR-ICP-MS and MC-ICP-MS respectively, in along a ~6 m peat section covering 5300 yr, from 30 BC to 5300 BC dated by the 14C method. Changes in REE concentration in the peat correlate with those of Ti, Al, Sc and Zr that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs and can be used as tracers of dust deposition. Peat humification and testate amoebae were used to evaluate hydroclimatic conditions. The range of dust deposition varied from 0.03 to 4.0 g m-2 yr-1. The highest dust fluxes were observed from 800 to 600 BC and from 3200 to 2800 BC and correspond to cold periods. The ?Nd values show a large variability of -5 to -13, identifying three major sources of dusts: local soils, distal volcanic and desert particles.

Allan, M.; Le Roux, G.; Piotrowska, N.; Beghin, J.; Javaux, E.; Court-Picon, M.; Mattielli, N.; Verheyden, S.; Fagel, N.

2013-05-01

14

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

15

Ombrotrophic peat bogs are not suited as natural archives to investigate the historical atmospheric deposition of perfluoroalkyl substances.  

PubMed

As ombrotrophic peat bogs receive only atmospheric input of contaminants, they have been identified as suitable natural archives for investigating historical depositions of airborne pollutants. To elucidate their suitability for determining the historical atmospheric contamination with perfluoroalkyl substances (PFAS), two peat cores were sampled at Mer Bleue, a bog located close to Ottawa, Canada. Peat cores were segmented, dried, and analyzed in duplicate for 25 PFASs (5 perfluororalkyl sulfonates (PFSAs), 13 perfluoroalkyl carboxylates (PFCAs), 7 perfluororalkyl sulfonamido substances). Peat samples were extracted by ultrasonication, cleaned up using a QuEChERS method, and PFASs were measured by HPLC-MS/MS. Twelve PFCAs and PFSAs were detected regularly in peat samples with perfluorooctane sulfonate (85-655 ng kg(-1)), perfluorooctanoate (150-390 ng kg(-1)), and perfluorononanoate (45-320 ng kg(-1)) at highest concentrations. Because of post depositional relocation processes within the peat cores, true or unbiased deposition fluxes (i.e., not affected by post depositional changes) could not be calculated. Apparent or biased deposition rates (i.e., affected by post depositional changes) were lower than measured/calculated deposition rates for similar urban or near-urban sites. Compared to PFAS production, PFAS concentration and deposition maxima were shifted about 30 years toward the past and some analytes were detected even in the oldest segments from the beginning of the 20th century. This was attributed to PFAS mobility in the peat profile. Considerable differences were observed between both peat cores and different PFASs. Overall, this study demonstrates that ombrotrophic bogs are not suited natural archives to provide authentic and reliable temporal trend data of historical atmospheric PFAS deposition. PMID:22680699

Dreyer, Annekatrin; Thuens, Sabine; Kirchgeorg, Torben; Radke, Michael

2012-07-17

16

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

17

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

18

History of atmospheric lead deposition since 12,370 (14)C yr BP from a peat bog, jura mountains, switzerland  

PubMed

A continuous record of atmospheric lead since 12,370 carbon-14 years before the present (14C yr BP) is preserved in a Swiss peat bog. Enhanced fluxes caused by climate changes reached their maxima 10, 590 (14)C yr BP (Younger Dryas) and 8230 (14)C yr BP. Soil erosion caused by forest clearing and agricultural tillage increased lead deposition after 5320 (14)C yr BP. Increasing lead/scandium and decreasing lead-206/lead-207 beginning 3000 (14)C yr BP indicate the beginning of lead pollution from mining and smelting, and anthropogenic sources have dominated lead emissions ever since. The greatest lead flux (15.7 milligrams per square meter per year in A.D. 1979) was 1570 times the natural, background value (0.01 milligram per square meter per year from 8030 to 5320 (14)C yr BP). PMID:9733502

Shotyk; Weiss; Appleby; Cheburkin; Gloor; Kramers; Reese; Van Der Knaap WO

1998-09-11

19

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

Microsoft Academic Search

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

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

1996-01-01

20

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

21

Comparative study of the temporal evolution of atmospheric lead deposition in Scotland and eastern Canada using blanket peat bogs.  

PubMed

The temporal evolution of atmospheric lead deposition and its possible sources were assessed in eastern Canada and in western Scotland, using blanket peat bogs as geochemical archives. Short cores were taken from two remote sites located close to the sea. Significant lead enrichments in the upper layers at both sites reflect the increasing emission of lead into the atmosphere due to anthropogenic activities during the last century. At the Scottish site, a region under aeolian influence from Europe, anthropogenic derived lead could be recognized by the distinctive unradiogenic composition (206Pb/207Pb ratios down to approximately 1.115), being clearly different from the pre-industrial values (206Pb/207Pb approximately 1.166). In contrast, the lead pollution in eastern Canada (influenced by North American sources) is identified by a more radiogenic lead isotope composition (206Pb/207Pb ratios up to approximately 1.199) compared to preindustrial values (206Pb/207Pb approximately 1.161). Emission inventories and isotope characteristics suggest that industrial (coal burning, mining) and traffic (leaded gasoline) outputs are the most likely sources during the first and the second half of the 20th century, respectively, in both, western Scotland and eastern Canada alike. The Scottish record is in line with previous studies of past atmospheric lead deposition. However, the Canadian deposit suggests that the wind derived, pre-industrial lead, is less radiogenic as previously implied using sediment archives. These results are thus the first to report pre-industrial lead isotope ratios and concentrations of atmospheric derived aerosols in North America. PMID:12108447

Weis, Dominik; Shotyk, William; Boyle, Edward A; Kramers, Jan D; Appleby, Peter G; Cheburkin, Andriy K

2002-06-20

22

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

23

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

24

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

25

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

26

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

27

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

28

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

29

Atmospheric deposition of silver and thallium since 12 370 14C years BP recorded by a Swiss peat bog profile, and comparison with lead and cadmium.  

PubMed

A peat core from an ombrotrophic bog in Switzerland provides the first complete, long-term record (14 500 years) of atmospheric Ag and Tl deposition. The lack of enrichment of Ag and Tl in the basal peat layer shows that mineral dissolution in the underlying sediments has not contributed measurably to the Ag and Tl inventories in the peat column, and that Ag and Tl were supplied exclusively by atmospheric deposition. The temporal and spatial distribution of modern peaks in Ag and Tl concentrations are similar to those of Pb which is known to be immobile in peat profiles. Silver and Tl, therefore, are effectively immobile in the peat bog also, allowing an atmospheric deposition chronology to be reconstructed. Silver concentrations vary by up to 114x and Tl up to 241x. While Holocene climate change and land use history can explain the variation in metal concentrations and enrichment factors (EF) in ancient peats (i.e. pre-dating the Roman Period), anthropogenic sources have to be invoked to explain the very high EF values (up to 123 in the case of Ag and 12 in the case of Tl) in peat samples since the middle of the 19th Century. The "natural background" EF of Tl in ancient peats is remarkably close to unity, indicating a lack of significant enrichment of this element in atmospheric aerosols due to chemical weathering of crustal rocks. Silver, on the other hand, shows a pronounced enrichment from 8030 to 5230 (14)C years BP (12x compared to crustal rocks); this may be due to weathering phenomena or biological processes, both of which are driven by climate. Even compared to the natural enrichment of Ag during the mid-Holocene, however, the enrichments of Ag and Tl in modern peats from the Industrial Period are at least an order of magnitude greater. The Pb/Ag and Tl/Ag ratios show that Pb and Tl are preferentially released, compared to Ag, during smelting of argentiferous Pb ores mined during the Roman and Medieval Periods. PMID:15152311

Shotyk, William; Krachler, Michael

2004-05-01

30

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

31

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

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

32

Uraniferous bitumen nodules in the Talvivaara Ni-Zn-Cu-Co deposit (Finland): influence of metamorphism on uranium mineralization in black shales  

NASA Astrophysics Data System (ADS)

In the central part of the Fennoscandian Shield, the Talvivaara Ni-Zn-Cu-Co deposit, hosted by Palaeoproterozoic metamorphosed black schists, contains low uranium concentrations ranging from 10 to 30 ppm. The Talvivaara black schists were deposited 2.0-1.9 Ga ago and underwent subsequent metamorphism during the 1.9-1.79 Ga Svecofennian orogeny. Anhedral uraninite crystals rimmed by bitumen constitute the main host of uranium. U-Pb secondary ion mass spectrometry dating indicates that uraninite crystals were formed between 1,878 ± 17 and 1,871 ± 43 Ma, during peak metamorphism. Rare earth element patterns and high Th content (average 6.38 wt%) in disseminated uraninite crystals indicate that U was concentrated during high temperature metamorphism (>400 °C). The formation of bitumen rims around uraninite may be explained by two distinct scenarios: (a) a transport of U coincident with the migration of hydrocarbons or (b) post-metamorphic formation of bitumen rims, through radiolytic polymerization of gaseous hydrocarbons at the contact with uraninite.

Lecomte, Andreï; Cathelineau, Michel; Deloule, Etienne; Brouand, Marc; Peiffert, Chantal; Loukola-Ruskeeniemi, Kirsti; Pohjolainen, Esa; Lahtinen, Hannu

2014-04-01

33

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

34

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

35

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

Microsoft Academic Search

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

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

2002-01-01

36

137Cs in a raised bog in central Sweden.  

PubMed

The vertical distribution of (137)Cs activity in peat soil profiles and (137)Cs 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 than 100 m from the open bog site and had slowly growing Scots pine, a field layer dominated by some ericaceous plants and ground well-covered by plants. The plant samples were collected in 2004-2007 and were compared with samples collected in 1989 from the same open bog and low pine sites. Ground deposition of (137)Cs in 2005 was similar at both sites, 23,000 Bq m(-2). In the open bog peat profile it seems to be an upward transport of caesium since a clear peak of (137)Cs activity was found in the uppermost 1-4 cm of Sphagnum layers, whereas at the low pine site (137)Cs was mainly found in deeper (10-12 cm) layers. The migration rate was 0.57 cm yr(-1) at the open bog site and the migration centre of (137)Cs was at a depth of 10.7, while the rate at the low pine site was 0.78 cm yr(-1) and the migration centre was at 14.9 cm. Heather (Calluna vulgaris) was the plant species with the highest (137)Cs activity concentrations at both sites, 43.5 k Bq(-1) DM in 1989 decreasing to 20.4 in 2004-2007 on open bog and 22.3 k Bq kg(-1) DM in 1989 decreasing to 11.2 k Bq(-1) DM by the period 2004-2007 on the low pine site. (137)Cs transfer factors in plants varied between 0.88 and 1.35 on the open bog and between 0.48 and 0.69 m(2)kg(-1) DM at the low pine site. PMID:19386400

Rosén, K; Vinichuk, M; Johanson, K J

2009-07-01

37

[Ophthalmopathologic findings in bog victims].  

PubMed

More than 1800 corpses found in European bogs have been described. Most were found in northwest Germany and Denmark. The 2700-year-old corpse of a young woman found in the Borremose fen in Denmark is described. The face was crushed, though injury during cutting of the peat was ruled out. Light and scanning electron microscopy revealed vessels both in the choroid of one eye and in one ear, with intravascular corpuscles--probably erythrocytes--but no extravascular hemorrhage. This means that the face was almost certainly crushed post mortem and during the winter. The cause of death is unknown. Very few of the other bog finds in Europe are well preserved, and even fewer have been pathologically studied or radiocarbon-dated. Interpretation of their fate is a very difficult, complex problem. One reason for this is that the corpses often remained buried for several thousand years, and they are often poorly preserved. The first descriptions of it were Roman, in particular Tacitus' Germania, which appeared in 98 AD--it is thus much younger than most of the corpses so far found. Tacitus talks of hanging, drowning, and ritual sacrifices. As regards future bog finds, it is suggested that an archaeologist, an anthropologist, a forensic expert and a taxi-dermist should be called in as soon as excavation begins. International cooperation between experts could prove very fruitful. PMID:2243483

Andersen, S R

1990-08-01

38

Borehole (slurry) mining of coal, uraniferous sandstone, oil sands, and phosphate ore. Report of Investigations/1987  

SciTech Connect

Advances in the art of borehole (slurry) mining and the design of a prototype borehole-mining tool (BMT) developed by the Bureau of Mines are presented along with production data, reclamation data, and an application of the BMT to the mining of coal, uraniferous sandstone, oil sands, and phosphate ore. The BMT was first used near Wilkeson, WA, where steeply pitching metallurgical was mined at 8 st/h from a depth of 25 to 75 ft. Next, 940 st of uraniferous sandstone was mine at 8 st/h from a depth of 75 to 100 ft in Natrona County, WY. One thousand short tons of oil sands was mined in Kern County, CA. at the rate of 14 st/h from a depth of 110 to 150 ft in 1979. Most recently, 1,700 st of phosphate ore was produced at 25 st/h from deep (230- to 250-ft) deposits in St. Johns County, FL. Progressive improvements were made in the borehole mining technique. These include the use of the hydrostatic head of a water-filled borehole for roof support and the development of methods to survey and backfill mined-out cavities.

Savanick, G.A.

1987-01-01

39

Results of reconnaissance for uraniferous coal, lignite, and carbonaceous shale in western Montana  

USGS Publications Warehouse

A reconnaissance search for uraniferous lignite and carbonaceous shale was made in western Montana and adjacent parts of Idaho during the summer of 1951. Particular emphasis in the examination was placed on coal and carbonaceous shale associated with volcanic rocks, as volcanic rocks in many areas appear to have released uranium to circulating ground water from which it was ,concentrated in carbonaceous material. Twenty-two areas in Montana and one area in Idaho were examined. The coal in five of these areas is of Cretaceous age. The coal and carbonaceous shale in the remaining 18 areas occur in Tertiary 'fake-bed' deposits of Oligocene and younger age. Both the Cretaceous and Tertiary coal and carbonaceous shale are associated with contemporaneous or younger volcanic rocks and pyrociastic sequences.

Hail, William James; Gill, James R.

1953-01-01

40

The butterfly fauna of Wisconsin bogs: lessons for conservation  

Microsoft Academic Search

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

Ann B. SwengelScott; Scott R. Swengel

2010-01-01

41

Large uraniferous springs and associated uranium minerals, Shirley Mountains, Carbon County, Wyoming -- A preliminary report  

USGS Publications Warehouse

Ten springs along the southeast flank of the Shirley Mountains, Carbon County, Wyoming, have water containing from 12 to 27 parts per billion uranium, have a total estimated flow of 3 million gallons of clear fresh water per day, and have a combined annual output that may be as much as 166 pounds of uranium. These springs emerge from Pennsylvanian, Permian, and Triassic rocks on the east flank of a faulted anticlinal fold. In the vicinity of several springs, metatyuyamunite occurs locally in crystalline calcite veins averaging 3 feet in width but reaching a maximum of 24 feet. The veins are as much as several hundred feet long-and cut vertically through sandstones of Pennsylvanian age overlying the Madison Limestone (Mississippian). This limestone is believed to be the source of the calcite. A 3-foot channel sample cross one calcite vein contains 0.089 percent uranium. Lesser amounts of uranium were obtained from other channel samples. Selected samples contain from 0.39 to 2.2 percent uranium and from 0.25 to 0.86 percent vanadium. Three possible sources of the uranium are: (1) Precambrian rocks, (2) Paleozoic rocks, (3) Pliocene(?) tuffaceous strata that were deposited unconformably across older .rocks in both the graphically high and low parts of the area, but were subsequently removed by erosion except for a few small remnants, one of which contains carnotite. There is apparently a close genetic relation between the uraniferous springs and uranium mineralization in the calcite veins. Data from this locality illustrate how uraniferous ground water can be used as a guide in the exploration for areas where uranium deposits may occur. Also demonstrated is the fact that significant quantities of uranium are present in water of some large flowing springs.

Love, J. D.

1963-01-01

42

Impact of raized bogs on export of carbon and river water chemical composition in Western Siberia  

NASA Astrophysics Data System (ADS)

Bogs play an important role in functioning of the biosphere. Specific geochemical environment of the bogs results in formation of the special biogeochemical cycle of the elements. Processes of decay and transformation of organic material define the reductive conditions of bog water, form and migratory mobility of the chemical elements. Particular interest in recent years is aroused by the question of content and dynamics of the carbon in bog and river water according to indicated natural and climatic changes on the territory. The most important parts of the carbon balance in bog ecosystems together with processes of exhalation from deposit surface in the form of CO2 is its export with river water. The results of research carried out in scientific station "Vasyugansky" in south taiga subzone of Western Siberia showed that chemical composition of raised bog water includes high amounts of total iron (2,13 mg/l), ammonium ions (5,33 mg/l), humic and fulvic acids (5,21 mg/l and 45,8 mg/l), dissolved organic carbon (69,1 mg/l), COD (236,93 mgO/l), there are low mineralization and indicators of pH. Carbon comes in bog water in organic compounds: carboxylic acids, phenols, aromatic and paraffin hydrocarbons, organic phosphates, phthalates and other compounds. Formation of river waters composition in the Western Siberia takes place in the following context: high level of bogged river catchments (sometimes up to 70%), excess humidification and low heat provision. Basing on the results of study of hydrochemical runoff in small and medium rivers with different levels of bogged in river catchments (Chaya, Bakchar, Klyuch, Gavrilovka) it was noted that raised bog influence on river waters chemical composition shows in ion runoff decrease, organic substances runoff increase, increase of amounts of total iron, ammonium irons and water pH indicators decrease. Study of humic matters migration is very important in the context of formation of flexible complexes of humic and fulvic acids and heavy metals, which should be taken into account when in waterlogged regions constructing large industrial projects and in formation of water removing.

Voistinova, Elena

2010-05-01

43

Bog Turtle ('Clemmys muhlenbergii') Recovery Plan.  

National Technical Information Service (NTIS)

Current Status: The northern population of the bog turtle was listed as a threatened species on November 4, 1997. This population is currently known to occur in Connecticut (5 sites), Delaware (4), Maryland (71), Massachusetts (3), New Jersey ( 165), New ...

M. Klemens

2001-01-01

44

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

45

Record of the meso- and neoholocene palaeoenvironmental changes in the Jesionowa landslide peat bog (Beskid S?decki MTS. Polish Outer Carpathians)  

Microsoft Academic Search

The paper presents an analysis of depositional sequences of landslide peat bog situated in the depressions developed within\\u000a the landslide landforms Jesionowa in the Beskid S?decki Mts. (Outer Carpathians). The peat bog, with depositional sequence\\u000a 2.80 m long, started to form at the beginning of the Atlantic Phase ca. 6390–5910 cal BC. Palynological and lithological analyses\\u000a as well as several

W?odzimierz Margielewski; Piotr Ko?aczek; Adam Michczy?ski; Andrzej Obidowicz; Anna Pazdur

2011-01-01

46

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

47

Study of naturally occurring, radionuclide bearing deposits at Portland Creek, Newfoundland.  

National Technical Information Service (NTIS)

A small uraniferous peat deposit located near Portland Creek, Newfoundland was investigated as part of the National Uranium Tailings Program (NUTP). The purpose of the investigation was to provide data on naturally occurring uranium series radionuclides a...

1985-01-01

48

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

49

Acidophilic Methanotrophic Communities from Sphagnum Peat Bogs  

Microsoft Academic Search

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

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

1998-01-01

50

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

51

Chemical Studies and Microscopic Examinations of the Organic Matter in Some Uraniferous Ore Bodies.  

National Technical Information Service (NTIS)

Uraniferous ore bodies are often accompanied by considerable concentrations of organic matter. Studies have been made of the organic matter in Francevillian samples from Oklo and in Permian samples from the Lodeve basin in France. Techniques derived from ...

A. M. Cassou J. Connan M. Correia J. J. Orgeval

1976-01-01

52

Results of reconnaissance for uraniferous coal, lignite, and carbonaceous shale in western Montana  

USGS Publications Warehouse

A reconnaissance search for uraniferous lignite and carbonaceous shale was made in western Montana and adjacent parts of Idaho during the summer of 1951. Particular emphasis in the examination was placed on coal and carbonaceous shale associated with volcanic rocks, as volcanic rocks in many area appear to have released uranium to circulating ground water from which it was concentrated in carbonaceous material. Twenty-two area in Montana and one area of Idaho were examine. The coal in five of these area is of Cretaceous age. The coal and carbonaceous shale in the remaining 18 area occur in Tertiary "lake-bed" deposits of Oligocene and younger age. Both the Cretaceous and Tertiary coal and carbonaceous shale are associated with contemporaneous or younger volcanic rocks and pyroclastic sequences. A sample of carbonaceous shale from the Prickly Pear Valley northeast of Helena, Montana, contained 0.013 percent uranium. A sample of carbonaceous shale from the Flint Creek Valley southwest of Drummond, Montana, contained 0.006 percent uranium. All other samples of both Cretaceous and Tertiary coal and carbonaceous shale were essentially non-radioactive. No further work is planned on the Cretaceous and Tertiary coal and carbonaceous shale in western Montana. A few localities in Idaho will be visited in the course of other work.

Hail, William J., Jr.; Gill, James R.

1952-01-01

53

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

54

Toxicity of Bog Water to Embryonic and Larval Anuran Amphibians.  

National Technical Information Service (NTIS)

A survey of the amphibians of a north temperate zone bog revealed that a number of species common in suitable locations nearby were absent from the bog. Several species of anuran larvae and embryos suffered high mortality when placed in the naturally acid...

P. A. Saber

1977-01-01

55

Isotopic evidence for nitrogen mobility in peat bogs  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

56

Geoinformatics meets education for a peat bog information system  

NASA Astrophysics Data System (ADS)

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

Michel, Ulrich; Fiene, Christina; Plass, Christian

2010-10-01

57

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

Microsoft Academic Search

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

Jonathan Price

1997-01-01

58

Smouldering bog wildfires and possible implications in palaeoenvironmental reconstructions  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

59

Borehole (slurry) mining of coal, uraniferous sandstone, oil sands, and phosphate ore. Report of Investigations\\/1987  

Microsoft Academic Search

Advances in the art of borehole (slurry) mining and the design of a prototype borehole-mining tool (BMT) developed by the Bureau of Mines are presented along with production data, reclamation data, and an application of the BMT to the mining of coal, uraniferous sandstone, oil sands, and phosphate ore. The BMT was first used near Wilkeson, WA, where steeply pitching

Savanick

1987-01-01

60

Borehole (slurry) mining of coal, uraniferous sandstone, oil sands, and phosphate ore  

Microsoft Academic Search

This paper reviews advances in the art of borehole (slurry) mining made by the Bureau of Mines from 1974 to 1980. The design of a prototype borehole-mining tool (BMT) developed by the Bureau of Mines is presented along with production data, reclamation data, and an application of the BMT to the mining of coal, uraniferous sandstone, oil sands, and phosphate

Savanick

1987-01-01

61

Borehole (slurry) mining of coal, uraniferous sandstone, oil sands, and phosphate ore  

SciTech Connect

This paper reviews advances in the art of borehole (slurry) mining made by the Bureau of Mines from 1974 to 1980. The design of a prototype borehole-mining tool (BMT) developed by the Bureau of Mines is presented along with production data, reclamation data, and an application of the BMT to the mining of coal, uraniferous sandstone, oil sands, and phosphate ore.

Savanick, G.A.

1987-01-01

62

Biogeochemistry and vegetation in a cranberry bog chronosequence  

Microsoft Academic Search

Abstract ,Abandoned cranberry bogs are becoming more abundant all over Cape Cod. I was interested in the vegetation trends over time in these abandoned agricultural systems and the biogeochemical,controls on these trends. I looked at fourteen abandoned,bogs and two active ones, all in southeasternMassachusetts, to create a 70+ year chronosequence. I compared the shrub and tree species composition, which included

Genevieve Noyce

2007-01-01

63

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

64

U-Pb ages of uraniferous opals and implications for the history of beryllium, fluorine, and uranium mineralization at Spor Mountain, Utah  

USGS Publications Warehouse

The U-Pb isotope systematics of uraniferous opals from Spor Mountain, Utah, were investigated to determine the suitability of such material for geochronologic purposes, and to estimate the timing of uranium and associated beryllium and fluorine mineralization. The results indicate that uraniferous opals can approximate a closed system for uranium and uranium daughters, so that dating samples as young as ???1 m.y. should be possible. In addition, the expected lack of initial 230Th and 231Pa in opals permits valuable information on the initial 234U/238U to be obtained on suitable samples of ???10 m.y. age. The oldest 207Pb/235U apparent age observed, 20.8 ?? 1 m.y., was that of the opal-fluorite core of a nodule from a beryllium deposit in the Spor Mountain Formation. This age is indistinguishable from that of fission-track and K-Ar ages from the host rhyolite, and links the mineralization to the first episode of alkali rhyolite magmatism and related hydrothermal activity at Spor Mountain. Successively younger ages of 13 m.y. and 8-9 m.y. on concentric outer zones of the same nodule indicate that opal formed either episodically or continuously for over 10 m.y. Several samples of both fracture-filling and massive-nodule opal associated with beryllium deposits gave 207Pb/235U apparent ages of 13-16 m.y., which may reflect a restricted period of mineralization or perhaps an averaging of 21- and <13-m.y. periods of opal growth. Several samples of fracture-filling opal in volcanic rocks as young as 6 m.y. gave 207Pb/235U ages of 3.4-4.8 m.y. These ages may reflect hot-spring activity after the last major eruption of alkali rhyolite. ?? 1980.

Ludwig, K. R.; Lindsey, D. A.; Zielinski, R. A.; Simmons, K. R.

1980-01-01

65

Non-polluting treatment of alkaline uraniferous effluents containing SO/sub 4/ ions  

SciTech Connect

A cyclic process for the treatment of a uraniferous liquor containing, in addition to the desired metal, sodium carbonate and/or bicarbonate and sodium sulphate, obtained by the alkaline attack of a sulphur-containing uraniferous ore, the said process comprising the neutralization of the uraniferous liquor then the fixation of the uranium and the SO/sub 4/ ions over a strong anion exchange resin, the elution thereof with an ammonium carbonate and/or bicarbonate solution in the form of an ammonium uranyl carbonate which is subsequently decomposed and ammonium sulphate, the precipitation and the calcination of the precipitated uranates and/or diuranates with regeneration of the eluent solution of ammonium carbonate and/or bicarbonate, the causticiation of the liquor freed from uranium which leaves the anion-exchange resin to eliminate the SO/sub 4/ ions in calcium form, recycling a carbonated and/or bicarbonated liquor which is free from SO/sub 4/ ions to the attack of the ore, finally the regeneration of the elution liquor of the SO/sub 4/ ions and of the uranium.

Berger, B.

1982-09-14

66

Evaluating Cumulative Effects of Disturbance on the Hydrologic Function of Bogs, Fens, and Mires.  

National Technical Information Service (NTIS)

Few quantitative studies have been done on the hydrology of fens, bogs and mires, and consequently any predictions of the cumulative impacts of disturbances on their hydrologic functions is extremely difficult. Bogs and fens are, in a sense, 'hydrobiologi...

D. I. Siegel

1988-01-01

67

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

PubMed

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

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

2013-12-01

68

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.

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

1998-01-01

69

Isotopic tracing of the source water for Cedar Bog in west-central Ohio, USA  

Microsoft Academic Search

Cedar Bog, a boreal fen in west-central Ohio, is home for many endangered plants and animals. The whereabouts of the water source that sustains Cedar Bog has been the subject of several investigations in the past two decades. Some of these studies indicated that a recharge area lies to the east and northeast of the Bog. Using environmental isotopes of

Songlin Cheng

1996-01-01

70

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

71

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.

72

Pb-Pb dating of hydrocarbon migration into a bitumen-bearing ore deposit, North Wales  

SciTech Connect

Previous attempts at U-Pb dating of uraniferous bitumens have had limited significance because of radioelement migration. Pb-Pb dating which can be undertaken regardless of recent lead migration, has been successfully applied to uraniferous solidified bitumen from the Ty Gwyn copper deposit, North Wales. Analyses of five bitumen samples with variable mixtures of radiogenic and common lead yield a {sup 207}Pb/{sup 206}Pb age of 248 {plus minus} 21 Ma (Early Triassic). This age is interpreted as the date of hydrocarbon migration into the deposit and is reasonably consistent with the timing of hydrocarbon generation calculated from the regional burial history. The Pb-Pb dating method could be applied to date uraniferous bitumens representing hydrocarbon migration in diverse geologic environments.

Parnell, J. (Queens's Univ., Belfast (Ireland)); Swainbank, I. (NERC Isotope Geology Centre, Nottingham (England))

1990-10-01

73

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

74

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

PubMed

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

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

2012-01-01

75

A Family of Bog Rotary Tillers (Semeistvo Bolotnykh Frez).  

National Technical Information Service (NTIS)

A family of rotary tillers is described for improving pastures and meadows. Designated as bog rotary tillers, they vary in width from .9 to 2.0 meters. Renovation of pastures with these tillers increased hay yields considerably; depending on the location ...

E. P. Yatsuk O. S. Marchenko V. F. Strelbitski V. A. Parkhomenko

1972-01-01

76

Evapotranspiration of Cut Over Bog Covered by 'Molinia Caerulea'.  

National Technical Information Service (NTIS)

During the months May to October in 1988 and in 1989, research was done at Engbertsdijksvenen (The Netherlands) on the evapotranspiration of Molinia caerulea growing on cut over bog. In 1988 the flux profile method was used to determine the actual evapotr...

E. J. Moors J. N. M. Stricker G. D. van den Abeele

1998-01-01

77

A Regional Comparison of the Long-Term Carbon Dynamics Within Maritime Peat Bogs Along the St. Lawrence North Shore, Northeastern Canada  

NASA Astrophysics Data System (ADS)

We have reconstructed the long-term carbon (C) dynamics within maritime bogs from two ecoclimatic regions between the Estuary (Baie-Comeau) and the Gulf of St. Lawrence (Havre-St.-Pierre) in northeastern Canada. The long-term average rates of C accumulation (LORCA) were calculated for eight peatlands. We also compared the Holocene variations in C sequestration between the peatlands to evaluate the influence of climate variability on their long-term C balance. The accumulation/decay processes were linked with changes in vegetation and water table depth. Overall, the LORCA decrease with the age of the peat deposits likely due to constant anoxic decay but they are significantly lower in Havre-St.-Pierre (16-46 g C m-2 yr-1) than in Baie-Comeau (53-68 g C m-2 yr-1). The regional differences in the LORCA reveal a pervasive climatic control on the long-term C balance. Our data suggest that the C accumulation in these bogs was driven by complex interactions between the peat accumulation/decay processes and the climate-mediated water table fluctuations. The higher C accumulation rates in the bogs of Baie-Comeau were promoted by stable ecohydrological conditions whereas the C balance in the bogs of Havre-St.-Pierre was more easily disrupted by past hydroclimatic changes especially during the Neoglacial cooling.

Magnan, G.; Garneau, M.

2013-12-01

78

Response of douglas fir (Pseudotsuga menziesii) to uraniferous groundwater in a small glaciated drainage, Northeastern Washington State  

USGS Publications Warehouse

Douglas fir trees and associated soils were sampled from the slopes of a small (??? 4 km2) drainage basin in northeastern Washington to investigate the biogeochemical response to locally uraniferous groundwater. Uranium is preferentially incorporated in needles and twigs compared to larger branches or the trunk. The U concentration in needle ash ranges from 0.2 to 5.8 ??g g-1 (ppm) and shows no correlation with the U concentration in associated soils. Rather, the distribution of anomalously uraniferous douglas fir (>1.0??g g-1 U in needle ash) appears to be controlled by observed or readily inferred pathways of near-surface groundwater movement in the drainage. These pathways include: (1) general downslope movement of subsurface runoff; (2) increased flux of near-surface groundwater near the toe of an alluvial fan; and (3) emergence of uraniferous (100-150 ng ml-1 [ppb] groundwater in the vicinity of a slope spring. The data also indicate the presence of near-surface uraniferous groundwater along a structurally controlled zone that parallels the north-south strike of the valley, and that includes the slope spring. The results suggest that biogeochemical sampling may be used to supplement more direct, but more limited, measurements of groundwater quality and flow regime in areas of near-surface contaminated groundwater. ?? 1987.

Zielinski, R. A.; Schumann, R. R.

1987-01-01

79

Response of douglas fir (Pseudotsuga menziesii) to uraniferous groundwater in a small glaciated drainage, Northeastern Washington State  

USGS Publications Warehouse

Douglas fir trees and associated soils were sampled from the slopes of a small (???4 km2) drainage basin in northeastern Washington to investigate the biogeochemical response to locally uraniferous groundwater. Uranium is preferentially incorporated in needles and twigs compared to larger branches or the trunk. The U concentration in needle ash ranges from 0.2 to 5.8??g g-1 (ppm) and shows no correlation with the U concentration in associated soils. Rather, the distribution of anomalously uraniferous douglas fir (> 1.0??g g-1 U in needle ash) appears to be controlled by observed or readily inferred pathways of near-surface groundwater movement in the drainage. These pathways include: (1) general downslope movement of subsurface runoff; (2) increased flux of near-surface groundwater near the toe of an alluvial fan; and (3) emergence of uraniferous (100-150 ng ml-1 [ppb] groundwater in the vicinity of a slope spring. The data also indicate the presence of near-surface uraniferous groundwater along a structurally controlled zone that parallels the north-south strike of the valley, and that includes the slope spring. The results suggest that biogeochemical sampling may be used to supplement more direct, but more limited, measurements of groundwater quality and flow regime in areas of near-surface contaminated groundwater. ?? 1987.

Zielinski, R. A.; Schumann, R. R.

1987-01-01

80

Stages of litter transformation in bog birch forests  

NASA Astrophysics Data System (ADS)

In the litters (peaty, weakly decomposed, and strongly decomposed) of bog birch forests, the biochemical transformation of plant material includes several discrete stages. The best prediction of the decomposition stages is the set of indices characterizing the humus status of the soils: the C/N ratio, (?HA + ?FA)/Cpolysaccharides, and the contents of humic and fulvic acids of fraction 1 in the groups of plant debris of different sizes. The discrimination of the litters according to the level of the biochemical transformation of the organic residues was observed when using the (?HA + ?FA)/Cpolysaccharides ratio, which is 6.3 in the peaty litter and 11.2 and 18.4 in the weakly decomposed and strongly decomposed litters, respectively. The biochemical classification of litters in the bog birch forests is in agreement with the morphological classification of litters.

Efremova, T. T.; Avrova, A. F.; Efremov, S. P.; Melent'eva, N. V.

2009-10-01

81

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

PubMed Central

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

Holzinger, Werner E.; Schlosser, Lydia

2013-01-01

82

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

83

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

Microsoft Academic Search

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

Tim E. Van Seters; Jonathan S. Price

2002-01-01

84

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

USGS Publications Warehouse

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

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

2006-01-01

85

Influence of uraniferous black shales on cadmium, molybdenum and selenium in soils and crop plants in the Deog-Pyoun-g area of Korea  

Microsoft Academic Search

The influence of naturally occurring uraniferous black shales on cadmium, molybdenum and selenium concentrations in soils\\u000a and plants is examined. The possible implications of element concentrations to animal and human health are considered for\\u000a the Deog-Pyoung area.\\u000a \\u000a Geochemical surveys have been undertaken within 13 river tributary valleys in the area underlain by uraniferous black shales\\u000a and black slates or grey

Kyoung-Woong Kim; Iain Thornton

1993-01-01

86

Late Holocene ecohydrological and carbon dynamics of a UK raised bog: impact of human activity and climate change  

NASA Astrophysics Data System (ADS)

Understanding the ecohydrological responses of peatlands to climate change is particularly challenging over the late Holocene owing to the confounding influence of anthropogenic activity. To address this, a core spanning the last ˜2400 years from a raised bog in northern England was analysed using a comprehensive suite of proxy methods in an attempt to elucidate the drivers of change. A testate amoebae-based transfer function was used to quantitatively reconstruct changes in water table depth, supported by humification analysis and a plant macrofossil-derived hydroclimatic index. Pollen and plant macrofossil data were used to examine regional and local vegetation change, and human impacts were inferred from charcoal and geochemistry. Chronological control was achieved through a Bayesian age-depth model based on AMS radiocarbon dates and spheroidal carbonaceous particles, from which peat and carbon accumulation rates were calculated. Phases of both increased and decreased bog surface wetness (inferred effective precipitation) are present, with dry phases at c. AD 320-830, AD 920-1190 and AD 1850-present, and a marked period of increased effective precipitation at c. AD 1460-1850. Coherence with other records from across Northern Europe suggests that these episodes are primarily driven by allogenic climatic change. Periods of high bog surface wetness correspond to the Wolf, Spörer and Maunder sunspot activity minima, suggesting solar forcing was a significant driver of climate change over the last ˜1000 years. Following the intensification of agriculture and industry over the last two centuries, the combined climatic and anthropogenic forcing effects become increasingly difficult to separate due to increases in atmospheric deposition of anthropogenically derived pollutants, fertilising compounds, and additions of wind-blown soil dust. We illustrate the need for multiproxy approaches based on high-resolution palaeoecology and geochemistry to examine the recent trajectories of peatlands.

Turner, T. Edward; Swindles, Graeme T.; Roucoux, Katherine H.

2014-01-01

87

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

SciTech Connect

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

Nikonov, V.V.

1981-01-01

88

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

89

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

Microsoft Academic Search

Few quantitative studies have been done on the hydrology of fens, bogs, and mires. Consequently predicting the cumulative impacts of disturbances on their hydrologic functions is extremely difficult. For example, few data are available on the role of bogs and fens with respect to flood desynchronization and shoreline anchoring. However, recent studies suggest that very small amounts of groundwater discharge

Donald I. Siegel

1988-01-01

90

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

EPA Science Inventory

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

91

[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

92

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

93

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

94

Superfund Record of Decision (EPA Region 2): Burnt Fly Bog, Marlboro Township, NJ., September 30, 1998.  

National Technical Information Service (NTIS)

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 Sit...

1999-01-01

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

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

97

Multiple gradients in mire vegetation: a comparison of a Swedish and an Italian bog  

Microsoft Academic Search

The major environmental gradients underlying plant species distribution were outlined in two climatically and bio-geographically contrasting mires: a Swedish bog in the boreo-nemoral zone, and an Italian bog in the south-eastern Alps. Data on mire morphology, surface hydrology, floristic composition, peat chemistry and pore-water chemistry were collected along transects from the mire margin (i.e., the outer portion of the mire

Luca Bragazza; Håkan Rydin; Renato Gerdol

2005-01-01

98

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

SciTech Connect

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

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

1989-09-01

99

The water balance as an approach to assessing groundwater dependency in raised bog wetlands  

NASA Astrophysics Data System (ADS)

The management of raised bogs, as active peat-forming ecosystems, requires an understanding of the relationships between regional hydrology and wetland ecohydrological processes. Marginal drainage, < 20 years, of Clara Bog, Ireland, has resulted in dramatic morphological changes. Differential peat consolidation has fragmented what was one topographic catchment area into four distinct catchment areas. Runoff has reduced by c. 40% from the original main catchment area and there has been a c. 25% decrease of suitably saturated areas supporting the growth of sphagnum moss species. In undisturbed bog systems the recharge rate of water seeping through the bog body to the regional groundwater table is in the order of 40 mm/ year. The downward seepage rate in Clara is > 100 mm/ year. A reduction in pore water pressure, due to drainage of the regional groundwater table, has disturbed the structure of the peat substratum and induced water loss from peat storage, resulting in the ecohydrological modification of the bog surface. Numerical modelling of a simulated raised groundwater table reduces the leakage rate to between 30 and 50 mm/ year. The significance is that the hydraulic gradient of the regional groundwater table is an important environmental supporting condition in raised bog ecosystems, implying indirect groundwater dependence.

Regan, Shane

2014-05-01

100

Exploratory study of suspended sediment concentrations downstream of harvested peat bogs.  

PubMed

Peat bog harvesting is an important industry in many countries, including Canada. To harvest peat, bogs are drained and drainage water is evacuated towards neighboring rivers, estuaries or coastal waters. High suspended sediment concentrations (SSC) were found in the drainage water at one particular site during the 2001-2002 spring seasons in New Brunswick (Canada). The main objective of this study was to verify this observation at other sites, compare SSC levels leaving harvested peat bogs with those leaving an unharvested bog, and to determine if high SSC events happen only in Spring or all year round. Suspended sediment concentrations were monitored downstream of three harvested peat bogs and an unharvested reference bog located in New Brunswick during the ice free seasons of 2003-2004. On average, SSC at the harvested sites exceeded 25 mg/l, which is the recommended daily maximum concentration, 72% of the time, while the same concentration was exceeded 30% of the time at the unharvested sites. SSC were found to be significantly higher at harvested sites than at the reference sites for all seasons. The highest SSC medians were recorded in the Fall but SSC was elevated in all seasons. High SSC levels in receiving waters may be caused by field ditching activities and insufficient sediment controls. Findings suggest the NB Peat Harvesting 25 mg/l SSC guideline should be reviewed. PMID:17505907

Pavey, Bronwyn; Saint-Hilaire, André; Courtenay, Simon; Ouarda, Taha; Bobée, Bernard

2007-12-01

101

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.

102

Non-polluting treatment of uraniferous effluents originating from an alkaline attack of a sulphur-containing uranium ore  

SciTech Connect

A cyclic process for the treatment of a uraniferous liquor containing, in addition to the desired metal, sodium carbonate and/or bicarbonate and sodium sulphate, obtained by the alkaline attack of a sulphur-containing uraniferous ore, the said process comprising fixing the uranium over a first strong anion-exchange resin, eluting it with an ammonium carbonate and/or bicarbonate solution in the form of an ammonium uranyl tricarbonate which is subsequently decomplexed, precipitating and calcinating the precipitated uranates and/or diuranates with regeneration of the eluant solution of ammonium carbonate and/or bicarbonate, passing the liquor which is freed from uranium and leaves the first strong anion-exchange resin into a neutralization zone then over a second anion-exchange resin, eliminating the SO/sub 4/= ions which are subsequently precipitated in calcium form, recycling a carbonate and/or bicarbonated liquor which is free from SO/sub 4/= ions to the attack of the ore, finally regenerating the elution liquor of SO/sub 4/= ions.

Berger, B.

1981-12-15

103

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

104

UâOâ production analysis for nonsandstone uranium deposits. Final report  

Microsoft Academic Search

The findings of an investigation into the commercialization potential of producing UâOâ from non-sandstone sources are presented. A variety of these non-conventional uranium resources were initially examined to arrive at a selection of seven major resource categories for detailed analysis. The seven categories are: (1) vein-type deposits, (2) wet process phosphoric acid, (3) copper leach solutions, (4) uraniferous coal, (5)

G. W. Toth; C. K. Chase; N. Lewis; W. L. Clem

1980-01-01

105

Can restoration convert a degraded bog in southern Bavaria to a carbon sink and climate cooler?  

NASA Astrophysics Data System (ADS)

The peatland area of Germany is about 14.000 km² (Succow & Joosten 2001) with 8% natural like bogs and 4% natural like fens (Höper 2006). All other peatland areas are more or less intensively used and thus, lost their sink function for carbon. If, theoretically, all German peatlands would be rewetted, this restoration would lead to a carbon mitigation of 9.5 Mio. t CO2-C equivalents (Freibauer et al. 2009). In test areas like the studied bog, the viability and potential of peatland restoration for climate mitigation can be proofed. The investigated bog is situated close to the Bavarian Alps; one part of this bog is extensively used and had been rewetted in 1993 except of a small stripe; management was stopped totally at another stripe. The second part of this bog had been drained without any further use. Here a Calluna heath established, accompanied by Pine trees. The restoration of this bog heath was done in two time steps; here a chronosequence of succession after restoration at different water table levels was investigated. To get to the greenhouse gas (GHG) balances of CO2 CH4 and N2O, gas flux measurements were done for two years using the chamber technique of Drösler (2005). At both areas, the degraded sites were sources for GHG (+203 to +736 g CO2-C-equiv m-2 a-1). Restoration reduced these emissions depending on water table and succession of bog species (-51 to +557 g CO2-C-equiv m-2 a-1). Depending on the vegetation's vitality GHG balances of already established natural like sites varied in between the years (-189 to +264 g CO2-C-equiv m-2 a-1) mainly driven by the oscillation of their water table. Stop of management and development of Sphagnum communities turned most of the sites into sinks for GHG (-216 to +7 g CO2-C-equiv m-2 a-1). Thus restoration turned degraded bogs efficiently to carbon sinks and climate coolers in dependence of a proper water table management, withdrawal of land use and vegetation succession. Key words: bog, greenhouse gases, restoration, water table

Förster, Christoph; Drösler, Matthias

2014-05-01

106

Content and binding forms of heavy metals, aluminium and phosphorus in bog iron ores from Poland.  

PubMed

Bog iron ores are widespread in Polish wetland soils used as meadows or pastures. They are suspected to contain high concentrations of heavy metals, which are precipitated together with Fe along a redox gradient. Therefore, soils with bog iron ore might be important sources for a heavy metal transfer from meadow plants into the food chain. However, this transfer depends on the different binding forms of heavy metals. The binding forms were quantified by sequential extraction analysis of heavy metals (Fe, Mn, Cr, Co, Ni, Cd, Pb) as well as Al and P on 13 representative samples of bog iron ores from central and southwestern Poland. Our results showed total contents of Cr, Co, Ni, Zn, Cd, and Pb not to exceed the natural values for sandy soils from Poland. Only the total Mn was slightly higher. The highest contents of all heavy metals have been obtained in iron oxide fractions V (occluded in noncrystalline and poorly crystalline Fe oxides) and VI (occluded in crystalline Fe oxides). The results show a distinct relationship between the content of Fe and the quantity of Zn and Pb as well P. Water soluble as well as plant available fractions were below the detection limit in most cases. From this we concluded bog iron ores not to be an actual, important source of heavy metals in the food chain. However, a remobilization of heavy metals might occur due to any reduction of iron oxides in bog iron ores, for example, by rising groundwater levels. PMID:19398508

Kaczorek, Danuta; Brümmer, Gerhard W; Sommer, Michael

2009-01-01

107

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

Microsoft Academic Search

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

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

1995-01-01

108

Changing sources of respiration between a black spruce forest and thermokarst bog  

NASA Astrophysics Data System (ADS)

Permafrost thaw in lowland black spruce forests (Picea mariana) which develop into thermokarst bogs can alter ecosystem carbon balance through positive or negative feedbacks to climate warming. In this context, the responses of plant and soil microbial communities to permafrost thaw, and their roles in altered carbon balance, need to be understood. In addition, gross changes in microbial community composition, such as fungal:bacterial ratios and their temperature response functions, are poorly characterized in permafrost thaw experiments. In this study, we compared carbon fluxes between a lowland black spruce forest with intact permafrost and an adjacent thermokarst bog that developed 20-30 years ago located near the Bonanza Creek Experimental Forest in Alaska. We quantified net ecosystem exchange (NEE), ecosystem respiration (ER), and gross primary productivity (GPP) using flux autochambers, and partitioned sources of ecosystem respiration into autotrophic vs. heterotrophic sources using radiocarbon analysis of ecosystem and microbial respiration, and atmospheric CO2. We further partitioned microbial respiration into fungal vs. bacterial sources using substrate inhibition techniques. Preliminary results indicate that in mid summer of 2011 the thermokarst bog was a source of CO2 to the atmosphere. NEE data indicated that the black spruce understory was a source of CO2. However, because flux tower data showed that the black spruce ecosystem was actually a net sink, GPP by the black spruce trees must have been large. In the black spruce forest ER was dominated by plant respiration in the spring and by microbial respiration in the fall whereas in the thermokarst bog CO2 was derived from deeper soil C sources. Although microbial respiration was roughly balanced between fungi and bacteria in the black spruce forest, respiration was dominantly bacterial in the thermokarst bog. Our initial results show that thermokarst bogs are source of C to the atmosphere during summer, which seems linked to bacterial access to deep C sources.

Waldrop, M. P.; McFarland, J.; Czimczik, C. I.; Euskirchen, E. S.; Amendolara, T.; Scott, G. J.; Turetsky, M. R.; Harden, J. W.; McGuire, A. D.

2011-12-01

109

Enhanced N Deposition and Peatland Carbon Stocks in Boreal Alberta  

NASA Astrophysics Data System (ADS)

Increased deposition of reactive nitrogen due to anthropogenic activities may stimulate plant growth and soil C turnover in N-limited ecosystems. Many peatland ecosystems are particularly sensitive to nitrogen deposition due their ombrotrophic nature. Here, we capitalize on a regional gradient of N deposition associated with several decades of oil sands mining. At six peatlands varying in atmospheric N loading (modeled from 1.45-3.26 kg N ha-1 yr-1), we measured Sphagnum fuscum net primary productivity (NPP). NPP rates were higher at Steepbank Bog (mean of 600 g m-2 yr-1) than at the five sites with lower N deposition (pooled mean of 182 g m-2 yr-1). At the site with the highest (Steepbank Bog) and lowest (Bleak Lake Bog) N loading, we quantified rates of C storage by 210Pb dating. Over the past 30 years of mining activity, rates of vertical peat accumulation were higher at Steepbank Bog (19.4 +/-0.4 cm) than at Bleak Lake Bog (13.9 +/-2.0 cm). However, there were no differences between sites in cumulative C storage over this 30-yr period (Steepbank: 5.0 +/-0.2 kg C m-2, Bleak Lake: 5.0 +/-0.4 kg C m-2). Together, these data suggest that increased N availability stimulates plant growth rates, leading to greater vertical accumulation of peat. However, enhanced N deposition does not appear to influence C storage in these sites, possibly due to lower peat bulk density and/or greater microbial activity.

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

2003-12-01

110

Atmospheric lead and heavy metal pollution records from a Belgian peat bog spanning the last two millenia: human impact on a regional to global scale.  

PubMed

Europe has been continuously polluted throughout the last two millennia. During the Roman Empire, these pollutions were mainly from ore extraction and smelting across Europe. Then, during the Middle Ages and the Early times of Industrial revolution (i.e. 1750), these pollutions extended to coal burning and combustion engine. Belgian ombrotrophic peat bogs have proved an effective archive of these pollutants and provide the opportunity to reconstruct the history of atmospheric deposition in NW Europe. The results of recent and past trace metal accumulation and Pb isotopes from a one-meter peat core (in the Misten peat bog) have been derived using XRF and Nu-plasma MC-ICP-MS. Combined with (14)C and (210)Pb dates these data have enabled us to trace fluxes in anthropogenic pollution back to original Roman times. Several periods of well-known Pb pollution events are clearly recorded including the Early and Late Roman Empire, the Middle Ages and the second industrial revolution. Also recorded is the introduction of leaded gasoline, and more recently the introduction of unleaded gasoline. Lead isotopes in this site have also enabled us to fingerprint several regional and global sources of anthropogenic particles. PMID:17379271

De Vleeschouwer, François; Gérard, Laëtitia; Goormaghtigh, Catherine; Mattielli, Nadine; Le Roux, Gaël; Fagel, Nathalie

2007-05-15

111

System for the Investigation of Peat Bog by Radar. Final Report. Stage 2.  

National Technical Information Service (NTIS)

The preliminary investigation of peat bog is facilitated by the use of radar. The continuous radar profiles make it possible to calculate the thickness of peat. An area of 240 ha has been investigated in less than 2 days by means of radar profiles 100 m a...

L. Bjelm P. Ulriksen

1982-01-01

112

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

Microsoft Academic Search

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

Izabella Surowiec; Anita Quye; Marek Trojanowicz

2006-01-01

113

Towards the identification of dyestuffs in Early Iron Age Scandinavian peat bog textiles  

Microsoft Academic Search

A large systematic dye investigation of prehistoric Danish and Norwegian bog textiles was carried out using high performance liquid chromatography with photo diode array detection. After the selection of the most suitable protocol for dye extraction and HPLC analysis for this specific group of archaeological samples, the second part included the characterisation of the dyes detected in the whole series

I. Vanden Berghe; Margarita Gleba; Ulla Mannering

2009-01-01

114

Superfund Record of Decision (EPA Region 2): Burnt Fly Bog Site, New Jersey, November 1983.  

National Technical Information Service (NTIS)

The Burnt Fly Bog site is located in Marlboro Township, Monmouth County and Old Bridge Township, Middlesex County, New Jersey. Between 1950 and 1956, the site had been used for lagoon storage and settling of reprocessed oil, storage of filter clay from oi...

1983-01-01

115

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

116

Health survey of wild and captive bog turtles (Clemmys muhlenbergii) in North Carolina and Virginia.  

PubMed

Blood samples, fecal samples, and cloacal swabs were collected from 42 bog turtles (Clemmys muhlenbergii). including 14 wild males, 22 wild females, three captive males, and three captive females, in Virginia and North Carolina, USA. Samples were analyzed for hematologic and plasma chemistry values, Mycoplasma sp. antibodies, intestinal parasites, and normal cloacal flora. PMID:12564526

Brenner, Deena; Lewbart, Gregory; Stebbins, Martha; Herman, Dennis W

2002-12-01

117

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

118

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

EPA Science Inventory

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

119

A survey of several soil physical characteristics of cultivated cranberry bog soils in North America  

Microsoft Academic Search

Cranberries (Vaccinium macrocarpon Ait.) historically have been established on peat based soils and, in most cases, are treated every three to five years with a 1–4 cm layer of sand. A total of 46 soil samples from cranberry bogs in five states [Massachusetts (MA), New Jersey (NJ), Oregon (OR), Washington (WA), and Wisconsin (WI)] and one Canadian province [British Columbia

J. R. Davenport; C. J. DeMoranville

1993-01-01

120

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

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

Lead isotope ratios in bone ash of blesbok (Damaliscus pygargus phillipsi): A means of screening for the accumulation of contaminants from uraniferous rocks.  

PubMed

This study was done to determine whether blesbok (Damaliscus pygargus phillipsi) from the Krugersdorp Game Reserve (KGR) in Gauteng Province, South Africa have higher concentrations of (238)U and higher (206)Pb/(204)Pb and (207)Pb/(204)Pb ratios in their bone ash than blesbok from a nearby control reserve that is not exposed to mine water and has no outcrops of uraniferous rocks. Eight blesbok females from the KGR and seven from the control site, all killed with a brain shot, were used. A Thermo X-series 2 quadrupole ICPMS was used to measure the concentrations of (238)U and lead and a Nu Instruments NuPlasma HR MC-ICP-MS to measure the lead isotope ratios in the tibial ash from each animal. KGR blesbok had higher mean concentrations of (238)U (P = 0.02) and ratios of (206)Pb/(204)Pb and (207)Pb/(204)Pb (P < 0.00001) than the control blesbok. The probability of rejecting the false null hypothesis of no difference in the (206)Pb/(204)Pb or (207)Pb/(204)Pb ratios between KGR and control reserve animals (the power of the test) was 0.999. The blesbok from the KGR accumulated contaminants from an uraniferous environment. The (206)Pb/(204)Pb and (207)Pb/(204)Pb ratios in tibial ash proved effective in confirming accumulation of contaminants from uraniferous rocks. PMID:24967558

Nöthling, Johan O; Du Toit, Johannes S; Myburgh, Jan G

2014-09-19

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

The aqueous geochemistry of uranium in a drainage containing uraniferous organic-rich sediments, Lake Tahoe area, Nevada, USA  

USGS Publications Warehouse

Anomalously uraniferous waters occur in a small (4.2 km2) drainage in the west-central Carson Range, Nevada, on the eastern side of Lake Tahoe. The waters transport uranium from local U-rich soils and bedrock to organic-rich valley-fill sediments where it is concentrated, but weakly bound. The dissolved U and the U that is potentially available from coexisting sediments pose a threat to the quality of drinking water that is taken from the drainage. The U concentration in samples of 6 stream, 11 spring and 7 near-surface waters ranged from 0.1 V). Possible precipitation of U(IV) minerals is predicted under the more reducing conditions that are particularly likely in near-surface waters, but the inhibitory effects of sluggish kinetics or organic complexing are not considered. These combined results suggest that a process such as adsorption or ion exchange, rather than mineral saturation, is the most probable mechanism for uranium fixation in the sediments. -Authors

Zielinski, R. A.; Otton, J. K.; Wanty, R. B.; Pierson, C. T.

1988-01-01

125

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

126

Tracing decadal environmental change in ombrotrophic bogs using diatoms from herbarium collections and transfer functions.  

PubMed

Central European mountain bogs, among the most valuable and threatened of habitats, were exposed to intensive human impact during the 20th century. We reconstructed the subrecent water chemistry and water-table depths using diatom based transfer functions calibrated from modern sampling. Herbarium Sphagnum specimens collected during the period 1918-1998 were used as a source of historic diatom samples. We classified samples into hummocks and hollows according to the identity of dominant Sphagnum species, to reduce bias caused by uneven sampling of particular microhabitats. Our results provide clear evidence for bog pollution by grazing during the period 1918-1947 and by undocumented aerial liming in the early 90-ies. We advocate use of herbarized epibryon as a source of information on subrecent conditions in recently polluted mires. PMID:23688732

Poulí?ková, Aloisie; Hájková, Petra; Kintrová, Kate?ina; Bat'ková, Romana; Czudková, Markéta; Hájek, Michal

2013-08-01

127

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

128

Investigation of gas exchange processes in peat bog ecosystems by means of innovative Raman gas spectroscopy.  

PubMed

Highly sensitive Raman gas spectroscopy is introduced for simultaneous real time analysis of O(2), CO(2), CH(4), and N(2) in order to elucidate the dynamics of greenhouse gases evolving from climate-sensitive ecosystems. The concentrations and fluxes of this suite of biogenic gases were quantified in the head space of a water-saturated, raised peat bog ecotron. The intact peat bog, exhibiting various degradation stages of peat and sphagnum moss, was exposed to various light regimes in order to determine important ecosystem parameters such as the maximum photosynthesis rate of the sphagnum as well as the extent of soil and plant respiration. Miniaturized Raman gas spectroscopy was proven to be an extremely versatile analytical technique that allows for onsite multigas analysis in high temporal resolution. Therefore it is an urgently needed tool for elucidation of complex biochemical processes especially in climate-sensitive ecosystems and consequently for the estimation of climate-relevant gas budgets. PMID:23320649

Frosch, Torsten; Keiner, Robert; Michalzik, Beate; Fischer, Bernhard; Popp, Jürgen

2013-02-01

129

Properties and structure of peat humic acids depending on humification and precursor biota in bogs  

NASA Astrophysics Data System (ADS)

Humic substances form most of the organic component of soil, peat and natural waters, but their structure and properties very much differs depending on their source. The aim of this study is to characterize humic acids from raised bog peat profiles to evaluate the homogeneity of humic acids isolated from the bog bodies and study peat humification impact on properties of humic acids. A major impact on the structure of peat humic acids have raised bog biota (dominantly represented by bryophytes of different origin) void of lignin. For characterization of peat humic acids their elemental (CHNOS), functional (-COOH, phenolic OH) analysis, spectroscopic characterization (UV, fluorescence, FTIR, 1H NMR, CP/MAS 13C NMR, ESR) and degradation studies (Py-GC/MS) were done. Peat humic acids (HA) 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, but thermodynamically more stable aromatic and polyaromatic structures emerge. Comparatively, the studied peat HAs are at the start of the transformation process of living organic matter. Concentrations of carboxyl and phenolic hydroxyl groups changes depending on the depth of peat from which HAs have been isolated: and carboxylic acidity is increasing with depth of peat location and the humification degree. The ability to influence the surface tension of peat humic acids isolated from a well-characterized bog profile demonstrates dependence on age and humification degree. With increase of the humification degree and age of humic acids, their molecular complexity and ability to influence surface tension decreases; even so, the impact of the biological precursor (peat-forming bryophytes and plants) can be identified.

Klavins, Maris; Purmalis, Oskars

2013-04-01

130

Carbon balance of a European mountain bog at contrasting stages of regeneration.  

PubMed

Carbon dioxide and methane (CH4) fluxes were measured in a cutover bog of the Jura Mountains (France) together with biotic and abiotic variables for two entire vegetation periods in order to compare the carbon balance of the bog at three stages of regeneration. Among all factors, air temperature and vegetation index (including leaf area of vascular plants, bryophyte density and bryophyte desiccation) were the two main determinants of ecosystem respiration and gross photosynthesis at light saturation. During 2004 and 2005, the vegetated plots acted as carbon sinks. Net carbon exchange ranged between 67 and 166 g C m(-2) yr(-1) for the Eriophorum-dominated plots and between 93 and 183 g C m(-2) yr(-1) for the Sphagnum-dominated plots. The bare peat plots represented a net carbon source (between -19 and -32 g C m(-2) yr(-1)). Methane fluxes accounted for a very small part of the total carbon efflux (< 2%). The recovery of vegetation in our naturally regenerating bog was beneficial for the carbon sequestration after the relatively short period of 20 yr. PMID:17096796

Bortoluzzi, Estelle; Epron, Daniel; Siegenthaler, Andy; Gilbert, Daniel; Buttler, Alexandre

2006-01-01

131

Water and energy exchanges of a subarctic bog in northern Quebec, Canada  

NASA Astrophysics Data System (ADS)

The La Grande Rivière watershed in northern Quebec, Canada, hosts the largest hydropower complex of the province, producing nearly 40% of the overall provincial peak load. Although the watershed is mostly occupied by boreal forest, wetlands (25% of the surface cover) play a key role in the hydrology of the region and on the water supply to hydropower reservoirs. This paper studies the water and energy budgets of a highly remote 60-ha bog (53.7°N, 78.2°W) inside the La Grande Rivière watershed near James Bay, with a main focus on the physical processes controlling evapotranspiration. The analysis is based on eddy covariance data collected during a summer field campaign in 2012, during which a network of 30 small lysimeters was also deployed to measure the spatial variability of daily evaporative fluxes. The applicability of Monin-Obukhov similarity scaling for humidity is carefully studied, along with a detailed analysis of atmospheric and soil (e.g. water table depth) controls on latent heat fluxes. We also study how the thermal inertia of the thick peat layer affects local turbulence properties in the atmospheric boundary layer, particularly under stable stratification. This study allows us to gain a better understanding of energy and water fluxes partitioning in subarctic bogs, but also to develop appropriate formulations for evaporation over these surfaces in hydrological models. Eddy correlation station installed over a subarctic bog in northern Quebec, Canada, during summer 2012.

Nadeau, D. F.; Rousseau, A. N.; Coursolle, C.; Margolis, H. A.

2012-12-01

132

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

133

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

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

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

NASA Astrophysics Data System (ADS)

Complete porewater profiles from two peat bogs in the Jura Mountains were analysed for major and trace inorganic anions and cations. At La Tourbière des Genevez (TGe) and Etang de la Gruère (EGr), peat formation began approximately 5,000 and 10,000 years BP, respectively. The maximum depths of peat accumulation are 140 cm (TGe) and 650 cm (EGr); previous geochemical studies showed that the ombrogenic sections of the bogs extend to depths of approximately 20 cm (TGe) and 250 cm (EGr). Water samples were obtained using in situ diffusion equilibrium samplers (peepers), which allow filtered (0.2 ?m) porewaters to be obtained while preventing degassing and oxidation. These samplers were found to be well suited to bog porewaters and allowed volatile (dissolved CO 2, acetate) and redox-sensitive species (HS -, Fe 2+) to be quantified without further sample preparation or treatment. Aqueous species concentrations were determined immediately afterwards using ion chromatography with either conductivity (acetate, HCO 3-, Cl -, Br -, NO 3-, HPO 42-, SO 42-, Na +, NH 4+, K +, Mg 2+, Ca 2+), amperometry (HS -), or absorbance detection (Fe(III) and Fe(II)). The comprehensive analyses of anions and cations allowed humic substances to be calculated by the difference in electrical charge balance (i.e., the anion deficit). Concentrations of total dissolved CO 2 (2-12 mM) showed that carbonate equilibria play a significant role in the acid-base chemistry throughout the profiles. In near surface, ombrogenic porewaters with pH around 4, however, protons (approx. 160 ?eq/L) are contributed mainly by the dissociation of humic substances (2-7 mM DOC). In the deepest, minerogenic layers H 2CO 3 is the predominant acid at both sites. At these depths, carbonate alkalinity (up to 3 meq/L at EGr, up to 8 meq/L at TGe) arises from reaction of the pore fluids with mineral matter in the underlying sediments. In the transition zone between the ombrogenic and minerogenic extremes, organic and inorganic acids are equal in importance. Unidentified organic S species accounted for 90-99% of total dissolved sulfur (S T) in the porewaters at TGe, with SO 42- and HS - the dominant inorganic species; S species with intermediate oxidation states such as SO 32- and S 2O 32- were always less than the detection limit of approximately 0.4 ?M. At TGe the sulfate concentrations exceeded those of sulfide, with 1.25 and 0.25 ?M, respectively, being typical. At EGr, S T and SO 42- were comparable to the waters at TGe, but HS - at EGr was always less than the detection limit of 0.15 ?M. At both sites dissimilatory sulfate reduction is limited by the low concentrations of sulfate supplied to the bog surfaces (i.e., atmospheric deposition only), and the uptake of sulfate and its conversion to organic S compounds by the living plants. Despite the anoxic condition of the waters, the ratio of Fe(III) T to Fe(II) T was always high: at EGr this ratio was generally 1:1, and even in the sulfidic waters at TGe the ratio was 1:3. PHREEQE was used to calculate the effect of complex-forming organic ligands on {Fe 3+} and {Fe 2+} in these porewaters. The relatively high ratios of Fe(III) T compared to Fe(II) T can be explained in terms of the much greater thermodynamic stability of the organic complexes of Fe 3+ compared to those of Fe 2+.

Steinmann, Philipp; Shotyk, William

1997-03-01

136

An examination of the mobilisation of elements from the skin and bone of the bog body Lindow II and a comparison with Lindow III  

Microsoft Academic Search

The elemental content of samples of tissues derived from a 2,000-year old bog body, Lindow II, are described and the interchange of elements between the body and the surrounding or encompassing anaerobic peat medium is examined. A comparison is made of the chemical ‘fingerprint’ of Lindow II as compared with another bog body referred to as Lindow III. The application

F. B. Pyatt; E. H. Beaumont; P. C. Buckland; D. Lacy; D. M. Storey

1991-01-01

137

Temperature-induced increase in methane release from peat bogs: a mesocosm experiment.  

PubMed

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; Damsté, Jaap S Sinninghe

2012-01-01

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.

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

2012-01-01

139

Impact of environmental factors on dissolved organic carbon concentrations in German bogs under grassland  

NASA Astrophysics Data System (ADS)

Peatlands cover about 5% of Germany's land area. Agricultural use combined with drainage increases the greenhouse gas emissions and alters the dissolved organic carbon (DOC) concentrations in the soil- and groundwater of these ecosystems. Cycling of DOC is influenced by a complex interaction of environmental factors such as peat characteristics, groundwater level, meteorological conditions, pH-value and ionic strength. Reasons for elevated DOC concentrations are debated in literature, but only a few studies on the dynamic of DOC in raised bogs in Germany have been conducted so far. In Germany, raised bogs are mainly used as grassland. Therefore, five grassland study sites and one natural reference have been selected. The bog "Ahlenmoor" has a deep, medium to weakly decomposed peat layer. There, three study sites represent different land use intensities with a corresponding groundwater table (intensive grassland, extensive grassland, natural reference). The bog relict "Großes Moor" is characterised by a shallow amorphous peat layer, which is partly mixed with sand. There, three sites in an extensive grassland were chosen to study the effects of soil carbon concentrations (9 to 48 %) and groundwater levels. At each site, nine suction plates (three replicates in each depth) and three tensiometers were installed in 15, 30 and 60 cm. Soil water was sampled fortnightly from June 2011 to December 2012 and analysed for electrical conductivity, pH-value and DOC concentration. Compared to most literature values, DOC concentrations at our study sites were very high (on average, 197 to 55 mg/L). At the "Ahlenmoor", an increase in agricultural intensity and a lower groundwater table increases both the DOC concentrations and their variability in the soil water in order intensive grassland > extensive grassland > natural site. Surprisingly, soil carbon concentration and groundwater table gradients as investigated in the "Großes Moor" did only lead to minor differences in the DOC concentrations. At these sites, the highest DOC concentrations were measured in the zone of transition between peat and mineral layer. No consistent relationship between DOC concentrations and electrical conductivity or pH-value could be found. In the "Ahlenmoor", seasonal variations of temperature and water table position influence DOC concentrations. The highest values were measured in late summer after warm and dry periods. At the study sites of the "Großes Moor", the seasonal variation of temperature and groundwater table had no impact on DOC concentrations. Our results show that while it is difficult to unravel all factors controlling DOC concentrations, drainage and physical disturbance clearly increase DOC concentrations.

Frank, Stefan; Tiemeyer, Bärbel; Freibauer, Annette

2013-04-01

140

Effects of Fire on Boreal Bogs and Implications of Climate Change  

NASA Astrophysics Data System (ADS)

Peatland ecosystems, which are predominantly found in northern boreal regions of Canada and Russia, accumulate carbon because photosynthetic production of the mosses dominating the ground layer exceeds their decomposition, thereby generating peat. Production and decomposition rates, and therefore peat accumulation, are species-specific and climatically controlled. While primary production of these systems is relatively low, the cold, wet, nutrient poor conditions found therein result in slow rates of decomposition. Therefore, changes in climate or vegetation composition will have an affect on boreal peatland function. Fire is the most prevalent disturbance for boreal peatlands of western Canada. Ombrotrophic, forested bog peatlands are most affected by fire due to a drier peat surface relative to other peatland landforms and an extensive Picea mariana canopy. In addition to direct C losses during peat combustion, fire has indirect affects on bog C cycling through removal of the ground layer vegetation and alteration of the surface environment. Because peat accumulation varies among species, functional recovery post-fire is linked to ground layer succession, which varies with combustion severity. To assess the post-fire compositional and functional recovery trajectories of western Canadian bogs, we monitored the ground layer community structure, production, and decomposition from 2003 to 2006 along a chronosequence of historically burned bogs (1-105 years since fire). Ground layer succession was tri-phasic, grading from pioneer true mosses early post-fire (1-10 ysf) to a Sphagnum-dominated community (20-80 ysf), followed by feathermoss encroachment at the longest recovery times (>90 ysf). However, the ground layer biomass production trajectory was asymptotic, stabilizing at ca. 20 years post-fire coinciding with Sphagnum dominance of the ground layer community. Decomposition in the upper peat column (top 40-cm) did not vary along the chronosequence, although surface (<2-cm) decomposition was not assessed. From our results, we developed models to assess the impact of an altered fire regime on peatland C storage. Increases in annual extent of wildfire and combustion severity under a 2xCO2 scenario substantially extend the peatland C pool recovery time. Furthermore, other models suggest a substantial reduction of the fire return interval (< 70 yrs) will cause peatlands to become sources, rather than sinks, of atmospheric C. Warming will enhance this effect, requiring less of a reduction in fire interval to trigger the functional switch.

Benscoter, B. W.; Vitt, D. H.; Wieder, R. K.

2007-12-01

141

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

142

Carbon Balance and Greenhouse Gas Fluxes in a Thermokarst Bog in Interior Alaska: Positive and Negative Feedbacks from Permafrost Thaw  

NASA Astrophysics Data System (ADS)

Climate change in northern latitudes is expected to cause widespread permafrost thaw in Interior Alaska over the 21st century. One result of permafrost thaw is land subsidence and the formation of thermokarst bogs. The net result of permafrost thaw on carbon (C) balance depends on the difference between forest floor carbon loss and Sphagnum productivity in the bog. However, greenhouse gas feedbacks including methane (CH4) and nitrous oxide (N2O) can be significant from a thawed saturated permafrost environment, strongly modifying the net climate forcing caused by CO2 exchange. We hypothesized that the saturated conditions in thermokarst bogs would decrease respiration compared to an intact permafrost forest, potentially promoting net CO2 uptake. However, CH4 and N2O production in the thermokarst bog may reduce any potential negative climate feedback. Our field sites are located at the Alaska Peatland Experiment (APEX), part of the Bonanza Creek LTER outside Fairbanks, Alaska. We examined net changes in C storage, greenhouse gas fluxes, and soil nutrients in a lowland black spruce forest with intact permafrost and an adjacent young thermokarst bog that developed 20-40 years ago. Using combined flux towers and autochambers (0.36 m2), we quantified net ecosystem exchange (NEE), ecosystem respiration (ER), and gross primary productivity (GPP). We also quantified semi-continuous CH4 fluxes using an isotopic CH4 analyzer (Picarro Inc) connected in-line to the autochambers, and N2O was measured using static chambers. Chamber measurements suggest that in mid-summer of 2012 the thermokarst bog was a net sink of CO2, while the understory black spruce was a net source. Furthermore, preliminary chamber measurements from 2012 indicate that thermokarst conditions have decreased respiration compared to the black spruce forest, potentially promoting net CO2 uptake in the bog. However, eddy covariance measurements of CO2 in 2011 indicate that the thermokarst bog was a source of CO2 while the black spruce forest was a sink. These contrasting patterns will be reconciled with environmental data and 2012 flux tower estimates. Carbon flux data will also be compared to decadal scale changes in ecosystem C balance through analysis of the loss rate of forest floor C and the accretion rate of bog C in soil cores from the thermokarst site. We were not able to detect significant N2O fluxes in the bog, but CH4 fluxes were significant. These data will be used to quantify the extent to which CH4 production in the bog may reduce any potential negative climate feedback. The data and understanding from these measurements will be incorporated into a peatland biogeochemistry model to assess the response of lowland black spruce in Interior Alaska to thawing permafrost caused by climate change.

Waldrop, M. P.; McFarland, J.; Euskirchen, E. S.; Turetsky, M. R.; Harden, J. W.; Manies, K.; Jones, M.; McGuire, A. D.

2012-12-01

143

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

USGS Publications Warehouse

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

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

2007-01-01

144

Behaviour of carbon dioxide and water vapour flux densities from a disturbed raised peat bog  

NASA Astrophysics Data System (ADS)

Measurements of carbon dioxide and water vapour flux densities were carried out for a disturbed raised peat bog in the north of the Netherlands during an 18 month continuous experiment. Tussock grass (sp. Molinea caerulae) mainly dominated the vegetation of the bog area. The maximum leaf area index (LAI) of the vegetation reached a numerical value of about 1.7 in mid-August.When the LAI is large enough (LAI > 0.2), a mean net uptake of carbon dioxide is observed with a clear daily pattern. The total evapotranspiration consists of a soil, an open water, and a plant transpiration part. When the LAI is large enough (LAI > 0.2), plant transpiration dominates the total evapotranspiration. The mean daily transpiration pattern, however, is not similar to the carbon dioxide uptake pattern.During the summer months, the daytime carbon dioxide uptake shows a single early morning maximum value followed by a decline in uptake during the rest of the day. The evapotranspiration, however, follows more or less the incoming short-wave radiation pattern. Effects of the vapour pressure deficit are suggested as a possible cause of this discrepancy.

Nieveen, Joost P.; Jacobs, Adrie F. G.

2002-10-01

145

[Mercury in the peat bog ecosystem in Xiaoxing'an mountain in China].  

PubMed

The mercury content in Tangwang River forested catchment of Xiaoxingan Mountain in Northeast of China was studied. The average total mercury (THg) in peat profile ranged from 65.8 ng/g to 186.6 ng/g with the highest in the depth of 5-10 m. THg in the peat surface was higher than the background in Heilongjiang province, and higher than the Florida Evergrade in America and Birkeness in Sweden. MeHg ranged from 0.16 ng/g to 1.86 ng/g with the highest in the depth of 10-15 cm. MeHg was 0.2-1.2% of THg. They all decreased with the depth. There was no strong significant correlation between the THg and MeHg (p = 0.05, r = 0.28). THg in upland mor layer of soil (0-20 cm) was comparable to the peat surface (0-20 cm), but in deeper layer THg in peat was much higher than the forested mineral soil. THg in the peat bog increased, but MeHg decreased after it was drained 30 years ago. THg in plant was different, THg in the moss (119 ng/g, n = 12) was much larger than the herbage, the arbor and the shrub. The peat bog was contaminated by mercury coming from the atmosphere to some degree. PMID:12371089

Liu, Ruhai; Wang, Qichao; Lü, Xianguo; Ma, Zhuangwei; Fang, Fengman

2002-07-01

146

Multiproxy investigation of climatic changes and human activities in a Baltic bog (N. Poland) during the last millennium.  

NASA Astrophysics Data System (ADS)

We present a multiproxy study carried out on a peat core retrieved from S?owi?skie B?ota bog (Pomerania, N-Poland). Several organic (palynology, plant macrofossils, testate amoebae, d13C) and inorganic (elemental geochemistry, lead isotopes) proxies were coupled to 210Pb-14C age-modelling in order to discriminate climatic and anthropogenic signals. Reconstruction of dust fluxes through time has remained a challenge, especially for tracing the nature of climatic changes. Although the idea of enhanced erosion conditions and storminess is commonly discussed, the conditions for dust deposition in peatlands over Europe during, for example, the ‘Little Ice Age' (LIA), are rarely favourable. Indeed the natural forest cover over Europe was much more important than nowadays, preventing dust deposition. Northern Poland, near the Baltic shore, was deforested just before the LIA (around AD 1100), and therefore constitutes a key area for the reconstruction of LIA climatic change. Our study of organic proxies evidences the LIA and is combined to our inorganic geochemical approach to validate our dust record. Overall, both organic and inorganic proxies show that LIA climatic changes are in good agreement with other records from Poland and NE Europe within a ca. 50yrs uncertainty. The severity of the LIA does however not affect the dynamism of mining activities over the last millennium. Indeed, during the LIA, Poland is experiencing its economical and cultural apogee, which can be seen by an increase in lead enrichment factors interpreted as an increase in mining activities. Lead, Zn, Cu, Ni concentrations and Pb isotopic ratios show that Polish Pb-Zn ores and coal were the main sources of Pb, as well as other heavy metals and S over Northern Poland until the industrial revolution. During the last century, leaded gasoline also contributed to anthropogenic Pb input over Poland. Coal and Pb-Zn ores, however, remained important sources of pollution in Eastern European countries during the last 50 years, as demonstrated by a high 206Pb/207Pb ratio (1.15) relative to the Pb isotopic signature of Western Europe (c. 1.10). The multiproxy record of S?owi?skie B?ota enhance the advantage of coupling geochemistry and biological proxies together with high-resolution age-modelling to better constrain the causes and consequences of both natural and anthropogenic changes during the last millennium.

de Vleeschouwer, François; Fagel, Nathalie; Piotrowska, Natalia; Sikorski, Jarek; Pawlyta, Jacek; Cheburkin, Andriy; Lamentowicz, Mariusz; Pazdur, Anna; Mattielli, Nadine; Renson, Virginie

2010-05-01

147

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

148

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

149

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

Microsoft Academic Search

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

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

1996-01-01

150

Development of floating rafts after the rewetting of cut-over bogs: the importance of peat quality  

Microsoft Academic Search

The usual method of restoring cut-over bogs is to rewet the peat surface, but this often leads to the remaining peat layers being deeply inundated. For Sphagnum-dominated vegetation to develop at deeply inundated locations, it is important for floating rafts of buoyant residual peat to develop. In this study, the chemical and physical characteristics of buoyant and inundated peat collected

Hilde B. M. Tomassen; Alfons J. P. Smolders; Leon P. M. Lamers; Jan G. M. Roelofs

2005-01-01

151

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

152

Superfund Record of Decision (EPA Region 2): Burnt Fly Bog, Marlboro Township, New Jersey, (1983, 1988, and 1998).  

National Technical Information Service (NTIS)

The Burnt Fly Bog Site is located in Marlboro Township, Monmouth County and Old Bridge Township, Middlesex County, New Jersey. Between 1950 and 1956, the site had been used for lagoon storage and settling of reprocessed oil, storage of filter clay from oi...

1984-01-01

153

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

154

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

Microsoft Academic Search

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

JEFFERY P. KOENINGS; FRANK F. HOOPER

1976-01-01

155

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

156

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

157

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

158

The Wonderful World of Wetlands (WWW): Bogs, fens, marshes and swamps and their global environmental significance  

NASA Astrophysics Data System (ADS)

Bogs, fens, marshes, and swamps are waterlogged ecosystems where organic soils form and peat accumulates. These are remarkably diverse ecosystems and represent an important component of the biodiversity found on Earth. Their geochemical function is dominated by their predominately anoxic condition which has some important consequences. Best known as reservoirs and reactors for a significant part of our surface freshwater resources, and impacting their chemical composition in remarkable ways, they also have a significant influence on the atmosphere, removing CO2 and adding CH4. The contemporary view during the past centuries was that these were wastelands in need of improving by drainage. Today, however, in some circles at least, the remaining wetlands are valued ecosystems, and the soils they contain archives of climate change, human history and atmospheric pollution.

Shotyk, W.

2012-04-01

159

Carbon balance of a boreal bog during a year with an exceptionally dry summer  

SciTech Connect

Northern peatlands are important terrestrial carbon stores, and they show large spatial and temporal variation in the atmospheric exchange of CO{sub 2} and CH{sub 4}. Thus, annual carbon balance must be studied in detail in order to predict the climatic responses of these ecosystems. Closed-chamber methods were used to study CO{sub 2} and CH{sub 4} in hollow, Sphagnum angustifolium lawn. S. fuscum lawn, and hummock microsites within an ombrotrophic S. fuscum bog. Micrometeorological tower measurements were used as a reference for the CH{sub 3} efflux from the bog. Low precipitation during May--August in 1994 and a warm July--August period caused the water table to drop by more than 15 cm below the peat surface in the hollows and to 48 cm below the surface in high hummocks. Increased annual total respiration exceeded gross production and resulted in a net C loss of 4--157 g/m{sup 2} in the different microsites. Drought probably caused irreversible desiccation in some lawns of S. angustifolium and S. balticum and in S. fuscum in the hummocks, while S. balticum growing in hollows retained its moisture and even increased its photosynthetic capacity during the July--August period. Seasonal (12 May--4 October) CH{sub 4} emissions ranged from 2 g CH{sub 4}-C/m{sup 2} in drier S. fuscum hummocks and lawns to 7 and 14 g/m{sup 2} in wetter S. angustifolium-S. balticum lawns and hollows, respectively.

Alm, J.; Silvola, J. [Univ. of Joensuu (Finland). Dept. of Biology; Schulman, L. [Univ. of Helsinki (Finland). Dept. of Ecology and Systematics; Walden, J. [Finnish Meteorological Inst., Helsinki (Finland); Nykaenen, H.; Martikainen, P.J. [National Public Health Inst., Kuopio (Finland). Lab. of Environmental Microbiology

1999-01-01

160

Halogens in porewater of peat bogs the role of peat decomposition and dissolved organic matter  

NASA Astrophysics Data System (ADS)

Peatlands are one of the largest active terrestrial reservoirs of halogens. Formation of organo-halogens is a key process for the retention of halogens by organic matter and halogen enrichment in peat is strongly influenced by climatically controlled humification processes. However, little is known about release and transport of halogens in peat bogs. In this study we investigated the release of halogens from peat in three peat bogs located in the Magellanic Moorlands, southern Chile. Peat porewaters were collected using a sipping technique, which allows in situ sampling down to a depth of more than 6 m. Halogens and halogen species in porewater were determined by ion-chromatography (IC) (chlorine) and IC-ICP-MS (bromine and iodine). Results show that halogen concentrations in porewater are 15-30 times higher than in rainwater suggesting that their release from peat during diagenesis is the major source of halogens in porewater. Mean concentrations of chlorine, bromine and iodine in porewater were 7-15 mg l-1, 56-123?g l-1, and 10-20?g l-1, which correspond to mean proportions of 10-15%, 1-2.3% and 0.5-2.2% of total concentrations in peat, respectively. Organo-bromine and organoiodine were predominant in porewaters, whereas the release of organo-chlorine compounds from peat appears to be of minor importance. Results show that the release of bromine and iodine from peat depend on the degree of peat degradation, whereas this relationship is weak for chlorine. Relatively higher release of bromine and iodine was observed in less degraded peat sections, where the release of dissolved organic carbon (DOC) was also the most intensive. Here, proportions of released iodine and bromine follow proportions of released dissolved organic matter (DOM) indicating that the release of halogenated DOM is the predominant process of iodine and bromine release from peat.

Biester, H.; Selimovi?, D.; Hemmerich, S.; Petri, M.

2005-09-01

161

Using stable isotopes of water to re-evaluate the recharge/discharge functions of North American bogs and fens  

NASA Astrophysics Data System (ADS)

In North American mires hydrologists commonly find raised bog crests and low-lying fen water tracks to be focal points for groundwater recharge and discharge, respectively. To further test these observations we synoptically surveyed vertical profiles of peat pore water ?18O/?2H and major mineral solutes from a range of bog and fen landforms across the Glacial Lake Agassiz Peatlands (GLAP) of northern Minnesota. We also sampled a detailed transect through a 150 km2 bog-fen complex in the Red Lake II peatland watershed of the GLAP. The molar ratios of Ca/Mg in the pore water beneath the Red Lake II bog crest are depleted in Mg with respect to the atmospheric average of 3.6, indicative of preferential flushing of Mg from the peat by meteoric recharge. Higher solute concentrations in the middle of the peat profile at an adjacent fen show focused groundwater discharge with Ca/Mg ratios of ~1.4, similar to that of water from local wells tapping underlying glacial till. However, contrary to expectations, we find evidence that modern recharge has penetrated throughout the peat column beneath both bog and fen landforms throughout the GLAP. Landform surface features control the isotopic recharge value. These landform-specific isotope signatures propagate through vertical pore water profiles. Pore waters deeper than 0.5 m partition into discrete ranges of ?18O according to three a priori landform classifications: 1) -11.9 ± 0.4 o for bog crests, 2) -10.6 ± 0.1 o for Sphagnum lawns, and 3) -8.8 ± 1.0 o for fen water tracks. The fen water tracks have standing water at their surface that is seasonally enriched by isotope fractionating evaporation and therefore fingerprints recharge to depths ?3 m. Incongruities between isotope and solute mixing trends may be related to the dual porosity nature of peat and matrix diffusion, which could supply solutes to active pore spaces following flushing by meteoric recharge. This buffering of base solutes in the deep peat may influence methanogenic bacteria that are sensitive to pH. Our results support the hypothesis that the downward transport of labile carbon substrates from the surface of northern peat basins fuels methane production in deeper peat strata.

Levy, Zeno; Siegel, Donald; Glaser, Paul; Dasgupta, Soumitri

2014-05-01

162

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

NASA Astrophysics Data System (ADS)

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 with lower GEP and ER, while at bogs wetter conditions were correlated with higher GEP and ER. We hypothesize that these contrasting responses are due to differences in the relative contributions of vascular plants and mosses. The coherence of our results between sites representing a range of average environmental conditions indicates ecosystem-scale differences in resilience to hydrological changes that should be taken into account when considering the future of peatland ecosystem services such as carbon sequestration under changing environmental conditions.

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

2010-10-01

163

Evaluation of the Phylogenetic Diversity of Prokaryotic Microorganisms in Sphagnum Peat Bogs by Means of Fluorescence In Situ Hybridization (FISH)  

Microsoft Academic Search

The microbial population of sphagnum peat bogs of northern Russia was analyzed with respect to the presence and cell numbers\\u000a of representatives of particular phylogenetic groups of prokaryotes by means of in situ hybridization with fluorescently labeled\\u000a group-specific rRNA-targeted oligonucleotide probes with broad detection spectra. The total number of cells that hybridized\\u000a with universal Archaea- and Bacteria-specific probes varied, in

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

2005-01-01

164

The palaeoecological history of the Praz-Rodet bog (Swiss Jura) based on pollen, plant macrofossils and testate amoebae (Prorozoa)  

Microsoft Academic Search

Abstract: Stratigraphy, radiocarbon dating and analyses of pollen, plant macrofossils and testate amoebae were used to reconstruct the development,and ecology of a small raised bog in a karst-dominated landscape in the Swiss Jura Mountains. Special focus was on past vegetation and on the history of Pinus rotundata in relation to anthropogenic,and climatic influences. Testate amoebae,were used to reconstruct past local

E. A. D. Mitchell; W. O. van der Knaap; J. f. n. Van Leeuwen; A. Buttler; B. G. Warner; J.-M. Gobat

2001-01-01

165

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

166

Accuracy assessment and position correction for low-cost non-differential GPS as applied on an industrial peat bog  

Microsoft Academic Search

A low-cost, non-differentially corrected hand-held GPS receiver was tested on an industrial peat production bog. A correction procedure (‘pseudo-differential correction’) was derived that corrected data points to the nearest position on a line defining the centre of each 15-m wide field. The result was a corrected log of track points for each field for all points lying along the field.

N. M. Holden; A. Comparetti; S. M. Ward; E. A. McGovern

1999-01-01

167

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

168

Fine-scale horizontal and vertical micro-distribution patterns of testate amoebae along a narrow Fen/Bog gradient.  

PubMed

The ecology of peatland testate amoebae is well studied along broad gradient from very wet (pool) to dry (hummock) micro-sites where testate amoebae are often found to respond primarily to the depth to water table (DWT). Much less is known on their responses to finer-scale gradients, and nothing is known of their possible response to phenolic compounds, which play a key role in carbon storage in peatlands. We studied the vertical (0-3, 3-6, and 6-9 cm sampling depths) micro-distribution patterns of testate amoebae in the same microhabitat (Sphagnum fallax lawn) along a narrow ecological gradient between a poor fen with an almost flat and homogeneous Sphagnum carpet (fen) and a "young bog" (bog) with more marked micro-topography and mosaic of poor fen and bog vegetation. We analyzed the relationships between the testate amoeba data and three sets of variables (1) "chemical" (pH, Eh potential, and conductivity), (2) "physical" (water temperature, altitude, i.e., Sphagnum mat micro-topography, and DWT), and (3) phenolic compounds in/from Sphagnum (water-soluble and primarily bound phenolics) as well as the habitat (fen/bog) and the sampling depth. Testate amoeba Shannon H' diversity, equitability J of communities, and total density peaked in lower parts of Sphagnum, but the patterns differed between the fen and bog micro-sites. Redundancy analyses revealed that testate amoeba communities differed significantly in relation to Eh, conductivity, water temperature, altitude, water-soluble phenolics, habitat, and sampling depth, but not to DWT, pH, or primarily bound phenolics. The sensitivity of testate amoebae to weak environmental gradients makes them particularly good integrators of micro-environmental variations and has implications for their use in paleoecology and environmental monitoring. The correlation between testate amoeba communities and the concentration of water-soluble phenolic suggests direct (e.g., physiological) and/or indirect (e.g., through impact on prey organisms) effects on testate amoebae, which requires further research. PMID:20938656

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

2011-02-01

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

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

171

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

172

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

173

Impact of long term wetting on pore water chemistry in a peat bog in Ontario, Canada  

NASA Astrophysics Data System (ADS)

Peatlands of the northern hemisphere store a remarkable amount of carbon but also contribute to global methane emissions. As large areas in the boreal and subarctic zone are considered to undergo significant climate change it is necessary to understand how these ecosystems react to altered environmental conditions. Since not only temperatures but also precipitation is likely to increase in these regions, it is of particular interest to understand the impact of raised water tables and changing local hydrological flow patterns on peatlands' carbon cycle. We chose a pristine bog that was partly flooded by a reservoir lake created 60 years ago in Ontario, Canada. Water management in the reservoir resulted in seasonal flooding, shifting hydrological flow patterns and vegetation gradients. The impact of partial flooding on pore water chemistry and DIC and CH4 concentrations were studied within surface peat layers. Samples were taken with pore water peepers along the vegetation- and flooding gradient. Turnover rates of DIC and methane were calculated from obtained concentration profiles and peat porosity under the assumption that transport is dominated by diffusion. Values of pH changed remarkably from 4 within the undisturbed bog part to almost 8 at the lake shore. Ca2+ and Mg2+ were the only ions that showed significant distribution patterns with readily increasing concentrations towards the lake water body. CH4 and DIC concentrations also increased towards the lake and peaked in around 100 cm depth right at the shore with maximum concentrations being 2766 ?mol L-1 for CH4 and 7543 ?mol L-1 for DIC, respectively. Turnover rates also increased towards the shore albeit some uncertainty lies in this finding as steady state condition required for calculations were probably not established and transport was not only dominated by diffusion. Maximum CH4 production rates were modeled to be 36 nmol cm-3 d-1 and maximum DIC production was calculated to 64 nmol cm-3 d-1. Ca2+ and Mg2+ concentration indicate lake water intrusion into the peat. Changes in pH are also probably due to lake water intrusion and altered plant communities. Vascular plant roots likely increased methanotrophy in subsurface layers but fuelled methanogenesis releasing labile carbon compounds in deeper layers. Modeling turnover rates gets exacerbated as other forms of gas transportation than diffusion prevail in vicinity to the lake. In addition to higher plant productivity lateral water flow is presumably the most important factor contributing to higher DIC and methane concentrations as it is thought to diminish the effect of end product inhibition in deeper peat layers towards the lake. We thus hypothesize that seasonal flooding not only affects ombrotrophic sites by nutrient inputs and subsequent changes in vegetation, but also due to altered hydrological flow patterns which will affect pore water chemistry and turnover rates by exchange of solutes and mineralization end products.

Schaper, Jonas; Blodau, Christian; Holger Knorr, Klaus

2013-04-01

174

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

NASA Astrophysics Data System (ADS)

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

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

2002-09-01

175

Connectivity and storage functions of channel fens and flat bogs in northern basins  

NASA Astrophysics Data System (ADS)

The hydrological response of low relief, wetland-dominated zones of discontinuous permafrost is poorly understood. This poses a major obstacle to the development of a physically meaningful meso-scale hydrological model for the Mackenzie basin, one of the world's largest northern basins. The present study examines the runoff response of five representative study basins (Scotty Creek, and the Jean-Marie, Birch, Blackstone and Martin Rivers) in the lower Liard River valley as a function of their major biophysical characteristics. High-resolution (4 m × 4 m) IKONOS satellite imagery was used in combination with aerial and ground verification surveys to classify the land cover, and to delineate the wetland area connected to the drainage system. Analysis of the annual hydrographs of each basin for the 4 year period 1997 to 2000, demonstrated that runoff was positively correlated with the drainage density, basin slope, and the percentage of the basin covered by channel fens, and was negatively correlated with the percentage of the basin covered by flat bogs. The detailed analysis of the water-level response to summer rainstorms at several nodes along the main drainage network in the Scotty Creek basin showed that the storm water was slowly routed through channel fens with an average flood-wave velocity of 0·23 km h-1. The flood-wave velocity appears to be controlled by channel slope and hydraulic roughness in a manner consistent with the Manning formula, suggesting that a roughness-based routing algorithm might be useful in large-scale hydrological models. Copyright

Quinton, W. L.; Hayashi, M.; Pietroniro, A.

2003-12-01

176

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

177

[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

178

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

179

Altitude or slope position - gaseous carbon cycling on UK blanket peat bogs  

NASA Astrophysics Data System (ADS)

Blanket peat accounts for 87% of Britain's total peatlands and represents one of the UK's largest terrestrial carbon stores. For peatlands to accumulate carbon the net ecosystem exchange of CO2 (NEE) must be negative with respect to the atmosphere. Unlike many other peatlands, upland blanket peat bogs in the UK are draped across hillsides and so it could be that both altitude and slope position are significant controls upon the magnitude and direction of NEE. The role that altitude and slope position play on NEE in upland blanket peat is poorly constrained on a local scale. Thus a hillslope transect was set up to measure how the gaseous exchange of CO2 varies across altitude and with slope position. The slope-transect consisted of 4 sites, in the English Peak District, with three replicates per site. The transect spanned the entire margin of peat occurrence on the hillside, from the summit (447m ASL) to the lowest occurrence of peat at (378m ASL). The sites were positioned to sample each of the distinct points of the variation in slope from the flat top, to the point of slope steepening, to the point of slope leveling to the final flattening out of the slope. Each site was located in Calluna vulgaris of similar age and in the same growth phase (degenerate). Data were gathered for a year in order to sample a complete seasonal cycle. The results of analysis by ANOVA showed that altitudinal effects were either not present or so small as to be masked by other effects. However both NER and GPP seemed to be linked to slope position. ANOVA and post hoc Tukey testing showed that only the site on the point of slope steepening was significantly different to the other sites with NER being 47% higher and GPP being 63% greater than the average of the other sites. But the elevated rates of GPP and NER cancelled each other out resulting in a non-significant 3% greater rate of overall NEE from the point of slope steepening. Another slope position effect observed was that of hill foot shading. This created markedly less variable readings than on the hill top sites, with the coefficients of variation being 70%, 40% and 36% greater on the hill top sites than hill foot sites for NEE, NER and GPP respectively. This suggests shading provides a more stable environment leading to more a spatially uniform gaseous carbon cycle within a single vegetation type.

Dixon, Simon; Rowson, James; Worrall, Fred

2010-05-01

180

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

SciTech Connect

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

Boyle, D.R.

1982-08-01

181

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

Microsoft Academic Search

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

William Shotyk

2010-01-01

182

Processes and mechanisms controlling consumption of CFC11 and CFC12 by peat from a conifer-swamp and black spruce-tamarack bog in New York State  

Microsoft Academic Search

We evaluated the potential consumption of chlorofluorocarbons CFC-11 and CFC-12 by peat soil from a conifer swamp and a temperate bog in New York State in order to assess whether extensive northern peatlands might serve as a sink for atmospheric CFCs. Intact peat cores maintained with an anoxic headspace over the peat surface consumed CFC-11 and minor amounts of CFC-12.

M. R. Bauer; J. B. Yavitt

1996-01-01

183

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

184

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

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

185

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

186

Are bogs reservoirs for emerging disease vectors? Evaluation of culicoides populations in the Hautes Fagnes Nature Reserve (Belgium).  

PubMed

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, François; Simonon, Grégory; Fagot, Jean; Haubruge, Eric; Francis, Frédéric; Losson, Bertrand

2013-01-01

187

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

188

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.

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

2013-01-01

189

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

PubMed

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

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

2012-07-01

190

Health assessment for Burnt Fly Bog National Priorities List Site, Marlboro, Monmouth County, New Jersey, Region 2. CERCLIS No. NJD980504997. Final report  

SciTech Connect

The Burnt Fly Bog site, a National Priorities List site, is located near Marlboro, Monmouth County, New Jersey in the fringe area of the New Jersey Pine Barrens. The major contaminants at the site are polychlorinated biphenyls (PCBs) and lead. Both of these contaminants have been found in all environmental media at the site. Exposure to contaminants may occur from contact with soil, sediment, water, air, or biota from the site. In order to protect the public health, access to contaminated areas should not be permitted except for properly-protected remedial workers. Because of the potential for ground-water contamination, private well owners surrounding the site should be advised to connect to the public water system. In addition, the consumption of game animals, berries, fish, and other biota from Burnt Fly Bog should be discouraged unless it can be determined that they are free of contamination.

Not Available

1988-08-24

191

Effects of short-term drying and irrigation on CO 2 and CH 4 production and emission from mesocosms of a northern bog and an alpine fen  

Microsoft Academic Search

Atmospheric CO2 and CH4 exchange in peatlands is controlled by water table levels and soil moisture, but impacts of short periods of dryness and\\u000a rainfall are poorly known. We conducted drying-rewetting experiments with mesocosms from an ombrotrophic northern bog and\\u000a an alpine, minerotrophic fen. Efflux of CO2 and CH4 was measured using static chambers and turnover and diffusion rates were

Marianna Deppe; Klaus-H. Knorr; Diane M. McKnight; Christian Blodau

2010-01-01

192

Methylocella palustris gen. nov., sp. nov., a new methane-oxidizing acidophilic bacterium from peat bogs, representing a novel subtype of serine-pathway methanotrophs  

Microsoft Academic Search

A new genus, Methylocella, and a new species, Methylocella palustris, are proposed for three strains of methane-oxidizing bacteria isolated from acidic Sphagnum peat bogs. These bacteria are aerobic, Gram-negative, colourless, non-motile, straight and curved rods that utilize the serine pathway for carbon assimilation, multiply by normal cell division and contain intracellular poly-b- hydroxybutyrate granules (one at each pole). These strains

Svetlana N. Dedysh; Werner Liesack; Valentina N. Khmelenina; Natalia E. Suzina; Yuri A. Trotsenko; Jeremy D. Semrau; Amy M. Bares; Nicolai S. Panikov; James M. Tiedje

193

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

194

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

NASA Astrophysics Data System (ADS)

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

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

195

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

SciTech Connect

Measurements of carbon dioxide concentration and flux were made above a raised open bog at Lake Kinosheo in the southern Hudson Bay lowlands during the Northern Wetlands Study (NOWES) experiment in 1990. Continuous concentration measurements by infrared gas analyzers (IRGA) and spot flask samples were taken over the period July 1 to July 29. Afternoon CO{sub 2} 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. CO{sub 2} 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/m{sup 2}/s by eddy correlation and -0.077 mg/m{sup 2}/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/m{sup 2}/s and +0.085 mg/m{sup 2}/s. Integration of the mean diurnal curve gave a net flux of -1.7 g/m{sup 2}/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/m{sup 2}/d. Typical net CO{sub 2} fluxes from other active temperature ecosystems have been found to be -10 to -20 g/m{sup 2}/d. Mean half hourly fluxes were almost constant at +0.06 mg/m{sup 2}/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. 20 refs., 9 figs., 1 tab.

Neumann, H.H.; Hartog, G. den [Atmospheric Environment Service, Ontario (Canada)] [Atmospheric Environment Service, Ontario (Canada); King, K.M.; Chipanshi, A.C. [Univ. of Guelph, Ontario (Canada)] [Univ. of Guelph, Ontario (Canada)

1994-01-20

196

Reconnaissance for radioactive deposits in eastern Alaska, 1952  

USGS Publications Warehouse

Reconnaissance for radioactive deposits was conducted in selected areas of eastern Alaska during 1952. Examination of copper, silver, and molybdenum occurrences and of a reported nickel prospect in the Slana-Nabesna and Chisana districts in the eastern Alaska Range revealed a maximum radioactivity of about 0.003 percent equivalent uranium. No appreciable radioactivity anomolies were indicated by aerial and foot traverses in the area. Reconnaissance for possible lode concentrations of uranium minerals in the vicinity of reported fluoride occurrences in the Hope Creek and Miller House-Circle Hot Springs areas of the Circle quadrangle and in the Fortymile district found a maximum of 0.055 percent equivalent uranium in a float fragment of ferruginous breccia in the Hope Creek area; analysis of samples obtained in the vicinity of the other fluoride occurrences showed a maximum of only 0.005 percent equivalent uranium. No uraniferous loads were discovered in the Koyukuk-Chandalar region, nor was the source of the monazite, previously reported in the placer concentrates from the Chandalar mining district, located. The source of the uranotheorianite in the placers at Gold Bench on the South Fork of the Koyukuk River was not found during a brief reconaissance, but a placer concentrate was obtained that contains 0.18 percent equivalent uranium. This concentrate is about ten times more radioactive than concentrates previously available from the area.

Nelson, Arthur Edward; West, Walter S.; Matzko, John J.

1954-01-01

197

Metallogeny, structural, lithological and time controls of ore deposition in anoxic environments  

NASA Astrophysics Data System (ADS)

Accumulation of metals in anoxic environments occurs by sorption and precipitation from seawater, fossil brines or hydrothermal solutions. Metals can be remobilized during subsequent metamorphic and magmatic processes and form ore deposits. This type of mineralization is governed chiefly by the type of tectonic setting of the anoxic environment. Carbonaceous sediments of passive margins contain only subeconomic concentrations of uranium, vanadium and molybdenum. Cubearing black shales and the submarine-exhalative type of mineralization are confined to the environments of continental rifts and aulacogens or to back-arc basins of active margins. Metamorphogenic deposits are mainly connected with collision margins but they may also occur in other types of tectonic environments. The formation of Cu-bearing black shales was controlled by period of low sea-level during the break-up of supercontinents in the Earth's evolution. Increased contents of uranium and vanadium accumulated in black shales in periods of sealevel highstands. Lithological control is apparent in deposits of Cu-bearing and uraniferous black shales. On the contrary, the occurrence of polymetallic mineralization does not depend on the lithological maturity of carbonaceous sediments.

K?íbek, B.

1991-04-01

198

Phosphor Deposition.  

National Technical Information Service (NTIS)

The method relates to the deposition of phosphor compounds in the manufacture of ray-sensitive tubes. The deposition is accomplished after tube exhaust. The method includes the use of one or more evaporator boats permanently secured within an envelope the...

H. A. Stern

1965-01-01

199

Assessing the controls of the snow energy balance in a shrub-covered bog in eastern Ontario, Canada  

NASA Astrophysics Data System (ADS)

The objectives of this study were to measure and evaluate the energy balance of a snowpack in a northern peatland, with a particular emphasis on the ground heat flux (G), and to evaluate the performance of a point energy and mass balance snowmelt model (SNOBAL) in peatland ecosystems. G is typically considered a small component of the snowpack energy balance (EB) when compared with radiative and turbulent fluxes. However, in environments where the soil temperature remains above freezing throughout the winter, G may be an important energy input to the snowpack. For direct assessment of the role of G in the snow energy budget of such an environment, the EB components of the snowpack at the Mer Bleue bog, a northern peatland, were directly measured and modelled using SNOBAL during the 2009-2010 winter. An 8 m tower mounted with a net radiometer, closed-path eddy covariance system, and supporting hydrometeorological instruments were used to quantify each form of energy transfer to the snowpack. In addition, snow surveys were conducted to determine snow depth, density, and snow water equivalent. When integrated over the pre-melt period, simulated and measured G proved to be a large contributor to the EB (25%). Net radiation and G were somewhat under-predicted by SNOBAL, whereas turbulent fluxes (especially latent heat fluxes, LE) were considerably over-predicted. G calculated by SNOBAL was found to be sensitive to the temperature gradient between the soil and the lower layer of the snowpack, whereas simulated turbulent fluxes were sensitive to the parameterization chosen to estimate roughness lengths for heat and water vapour.

Carey, S. K.; Knox, S.; Humphreys, E.

2012-12-01

200

Ditch blocking, water chemistry and organic carbon flux: evidence that blanket bog restoration reduces erosion and fluvial carbon loss.  

PubMed

The potential for restoration of peatlands to deliver benefits beyond habitat restoration is poorly understood. There may be impacts on discharge water quality, peat erosion, flow rates and flood risk, and nutrient fluxes. This study aimed to assess the impact of drain blocking, as a form of peatland restoration, on an upland blanket bog, by measuring water chemistry and colour, and loss of both dissolved (DOC) and particulate organic carbon (POC). The restoration work was designed to permit the collection of a robust experimental dataset over a landscape scale, with data covering up to 3 years pre-restoration and up to 3 years post-restoration. An information theoretic approach to data analyses provided evidence of a recovery of water chemistry towards more 'natural' conditions, and showed strong declines in the production of water colour. Drain blocking led to increases in the E4:E6 ratio, and declines in specific absorbance, suggesting that DOC released from blocked drains consisted of lighter, less humic and less decomposed carbon. Whilst concentrations of DOC showed slight increases in drains and streams after blocking, instantaneous yields of both DOC and POC declined markedly in streams over the first year post-restoration. Attempts were made to estimate total annual fluvial organic carbon fluxes for the study site, and although errors around these estimates remain considerable, there is strong evidence of a large reduction in aquatic organic carbon flux from the peatland following drain-blocking. Potential mechanisms for the observed changes in water chemistry and organic carbon release are discussed, and we highlight the need for more detailed information, from more sites, to better understand the full impacts of peatland restoration on carbon storage and release. PMID:21440287

Wilson, Lorraine; Wilson, Jared; Holden, Joseph; Johnstone, Ian; Armstrong, Alona; Morris, Michael

2011-05-01

201

Lake and Bog Sediment Records of Holocene Climate and Glacier Variability in the Cordillera Vilcabamba of Southern Peru  

NASA Astrophysics Data System (ADS)

Records of past fluctuations in climatically sensitive tropical glaciers are among the best indicators of regional paleoclimatic trends and forcings. However, continuous sediment records in this region remain limited, particularly during the Holocene. Here we present the first continuous records of glacier activity in the Cordillera Vilcabamba (13°20'S) of southern Peru from lake and bog sediment cores in stratigraphic contact with 10Be-dated moraines. Completed analyses include sediment lithostratigraphy, magnetic susceptibility, and biogenic silica, in conjunction with AMS radiocarbon dates on charcoal. Carbon measurements, bulk density, and bulk sedimentation rates are used to derive a record of clastic sediment flux that serves as a proxy indicator of former glacier activity. Visually distinct sedimentological variations, magnetic susceptibility peaks, and radiocarbon dates were correlated among adjacent cores to construct one composite record representative of each coring site. Three composite cores are presented: two from the Rio Blanco valley and one from the Yanama valley. Sediment records from these two glaciated valleys suggest a series of environmental changes during the last ~12,000 calendar years BP. Clastic sediment flux trends are broadly consistent with published evidence that the early to middle Holocene was relatively warm and arid in the southern Peruvian Andes. An episode of high clastic flux in the late Holocene may reflect enhanced glacial activity in response to the onset of cooler and wetter conditions. A prominent peak in magnetic susceptibility at 1660 cal yr BP is present in all composite cores and serves as a chronostratigraphic marker. In addition, our new basal radiocarbon ages place limits on the cosmogenic 10Be production rate in the high Andes, suggesting the cosmogenic 10Be production rate is considerably lower than previously published estimates.

Schweinsberg, A.; Licciardi, J. M.; Rodbell, D. T.; Stansell, N.

2013-12-01

202

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

SciTech Connect

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

Goodwin, S.; Zeikus, G.J.

1987-01-01

203

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

USGS Publications Warehouse

In this study, we sought to determine the population stability and genetic diversity of one isolated population of the federally-threatened bog turtle (Glyptemys muhlenbergii) in North Carolina. Using capture-recapture data, we estimated adult survival and population growth rate from 1992 to 2007. We found that the population decreased from an estimated 36 adult turtles in 1994 to approximately 11 adult turtles in 2007. We found a constant adult survival of 0. 893 (SE = 0. 018, 95% confidence interval, 0. 853-0. 924) between 1992 and 2007. Using 18 microsatellite markers, we compared the genetic status of this population with five other bog turtle populations. The target population displayed allelic richness (4. 8 ?? 0. 5) and observed heterozygosity (0. 619 ?? 0. 064) within the range of the other bog turtle populations. Coalescent analysis of population growth rate, effective population size, and timing of population structuring event also indicated the genetics of the target population were comparable to the other populations studied. Estimates of effective population size were a proportion of the census size in all populations except the target population, in which the effective population size was larger than the census size (30 turtles vs. 11 turtles). We attribute the high genetic diversity in the target population to the presence of multiple generations of old turtles. This study illustrates that the demographic status of populations of long-lived species may not be reflected genetically if a decline occurred recently. Consequently, the genetic integrity of populations of long-lived animals experiencing rapid demographic bottlenecks may be preserved through conservation efforts effective in addressing demographic problems. ?? 2011 Springer Science+Business Media B.V.

Pittman, S. E.; King, T. L.; Faurby, S.; Dorcas, M. E.

2011-01-01

204

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

205

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

206

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

207

Organic matter deposition in the Saskatchewan River floodplain (Cumberland Marshes, Canada): effects of progradational avulsions  

NASA Astrophysics Data System (ADS)

This paper examines organic matter deposition in the avulsion-controlled floodplain of the Saskatchewan River at the Cumberland Marshes, east-central Saskatchewan. Organic-rich deposits were formed throughout the late Holocene in fen/bog (coarse brown peat) and lacustrine (fine dark-brown and black organic-rich mud) environments. The thicknesses of individual organic-rich layers reach 3.2 m but are typically less than 1 m thick. Lateral extents of these beds are limited by elevated alluvial ridges, but they may attain exceptional dimensions of 15 km in transverse and 50 km in longitudinal directions. Conditions for organic deposition on avulsion-controlled floodplains appear to be different from those on other floodplains. In addition to floods, terrigenous sediments are delivered by progradational avulsions into parts of the floodbasin previously accumulating organic-rich sediments. Elevated alluvial ridges resulting from former avulsions, however, block large parts of the floodplain from normal flooding and therefore prevent clastic deposition. Total organic content of floodplain sediments is inversely related to sediment grain size and sedimentation rate. The composition of organic-rich layers reflects a predominantly progradational avulsion style. The center portions of many organic-rich layers are commonly composed of brown fen/bog peat overlain successively by organic-rich and organic-poor lacustrine mud, eventually passing upwards into coarser deposits. The rate of avulsive progradation is roughly reflected in the vertical organic-content gradient within the alluvial sections. Rapid progradation, typical for most portions of the most recent (1870's) avulsion belt, results in relatively abrupt changes of organic content, whereas slower progradation is accompanied by more gradual decreases in organic content.

Morozova, Galina S.; Smith, Norman D.

2003-03-01

208

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

209

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

210

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

211

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

212

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

213

Deposition Equipment  

NSDL National Science Digital Library

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

2012-12-21

214

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

215

Export of dissolved organic carbon and nitrogen from drained and re-wetted bog sites in Lower Saxony (Germany)  

NASA Astrophysics Data System (ADS)

Today, nearly all peatlands in Germany are drained for agriculture, forestry and peat cutting. The export of dissolved organic carbon (C) and nitrogen (N) may be important for the overall C and N balances and affects downstream ecosystems. While drainage generally increases solute losses, there is nearly no C and N export data of raised bogs in Germany which can be used to evaluate both the impact of drainage associated with intensive land use and the re-wetting of peat cutting sites. In the "Ahlenmoor" (North-Western Germany), four sampling points were chosen. Three sampling points represent a deeply drained intensively used grassland at various scales ranging from a drainage pipe (DP, 0.08 ha) and a drainage ditch (DD, 6.8 ha) to a collector ditch (CD, 20 ha). The fourth sampling point (RW) is a former peat cutting site (23 ha) re-wetted 10 years ago. At this site, polder technique was used to establish water tables at the soil surface. Sampling and discharge measurements were conducted bi-weekly from June 2011 to June 2013. Water table levels were recorded with automatic pressure sensors, and rating curves between discharge and water levels were used to calculate continuous discharge values. Samples were analyzed for dissolved organic carbon (DOC), particulate organic carbon (POC), dissolved organic nitrogen (DON), ammonium (NH4+), nitrate (NO3-), sulphate (SO42-), pH, electric conductivity (EC) and specific UV absorbance (SUVA). The discharge did not vary strongly between the sampling points and was slightly lower in the second year. Concentrations of all measured solutes were higher at the intensive grassland (DP, DD and CD) than at the re-wetted site. Surprisingly, SUVA showed no difference between all sites, while the DOC to DON ratio was narrower at DP, DD and CD than at RW. This indicates an export of more degraded dissolved organic matter (DOM) from the drained area. At the grassland sites, no statistical differences were found between the three scales except for SO42-, NO3- and pH. Thus, the grassland shows rather homogenous export patterns over various spatial scales, and there seem to be no fast mineralization or degradation of the exported DOM during the initial stage of export. In total, average losses of DOC (457 kg ha-1 a-1) and POC (40 kg ha-1 a-1) from the drained area were nearly thrice as high as from the re-wetted site (124 and 73 kg ha-1 a-1). The total nitrogen losses were even more reduced by re-wetting and dominated at all sites by DON (19.1 kg ha-1 a-1 at the grassland sites, 3.9 kg ha-1 a-1 at the re-wetted site). NH4+ (drained: 5.2 kg ha-1 a-1, re-wetted: 0.8 kg ha-1 a-1) and NO3- (drained: 1.6 kg ha-1 a-1, re-wetted: not detectable) played a minor role. Overall, differences in the export could rather be explained by differences in solute concentration than in discharge.

Frank, Stefan; Tiemeyer, Bärbel; Freibauer, Annette

2014-05-01

216

The geochemistry of water near a surficial organic-rich uranium deposit, northeastern Washington State, U.S.A.  

USGS Publications Warehouse

The chemistry of three stream, three spring and six near-surface waters in the vicinity of a Holocene organic-rich uranium deposit is described, with particular emphasis on the chemistry of U. Results characterize the solution behavior of uranium as U-bearing water interacts with relatively undecomposed, surficial organic matter. Of the measured major and trace chemical species, only U is consistently highly enriched (17-318 ppb) relative to reported values for regional waters, or to literature values for waters in largely granitic terrains. R-mode factor analysis of the chemical data suggests that most U is present in a soluble form, but that some U is also associated with fine suspended particulates of clay, organic matter, or hydrous oxides. Calculations that apply thermodynamic data to predict U speciation in solution indicate the relative importance of uranyl carbonate and uranyl phosphate complexes. Analysis of more finely filtered samples (0.05 ??m vs. 0.45 ??m), and direct radiographic observations using fission-track detectors suspended in the waters indicate the presence of some uraniferous particulate matter. Application of existing thermodynamic data for uranous- and uranyl-bearing minerals indicates that all waters are undersaturated with U minerals as long as ambient Eh ??? +0.1 v. If coexisting surface and near-surface waters are sufficiently oxidizing, initial fixation of U in the deposit should be by a mechanism of adsorption. Alternatively, more reducing conditions may prevail in deeper pore waters of the organic-rich host sediments, perhaps leading to direct precipitation or diagenetic formation of U4+ minerals. A 234U 238U alpha activity ratio of 1.08 ?? 0.02 in a spring issuing from a hillslope above the deposit suggests a relatively soluble source of U. In contrast, higher activity ratios of 234U 238U (??? 1.3) in waters in contact with the uraniferous valley-fill sediments suggest differences in the nature of interaction between groundwater and the local, U-rich source rocks. ?? 1987.

Zielinski, R. A.; Otton, J. K.; Wanty, R. B.; Pierson, C. T.

1987-01-01

217

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...

218

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.

219

Natural bog pine ecosystem in southern Germany is a steady and robust sink of CO2 but a minor source of CH4  

NASA Astrophysics Data System (ADS)

Natural peatland ecosystems sequester carbon dioxide. They do this slowly but steadily, but also emit methane in small rates. Thus peatlands have both positive and negative greenhouse gas balance impacts on the climate system due to their influence on atmospheric CO2 and CH4 concentration. We present data of net ecosystem CO2 exchange (NEE) of almost three years (July 2010 to March 2013) and of methane fluxes over a period of nine months (July 2012 to March 2013), measured by eddy covariance technique in the bog forest "Schechenfilz". The site (47°48' N; 11°19' E, 590 m a.s.l.) is an ICOS-ecosystems associate site, located in the pre-alpine region of southern Germany, where a natural Pinus mugo rotundata forest grows on an undisturbed, almost 6 m thick peat layer. The slow growing bog pines and their low rates of carbon sequestration, in combination with high water table and thus low availability of oxygen, lead to low carbon dioxide fluxes. Photosynthesis as well as soil respiration are considerably attenuated compared to upland sites. Additionally, the high soil water content is damping the impact of dry and hot periods on CO2 exchange. Thus the CO2 balance is very robust to changing environmental parameters. While the CO2 exchange is clearly related to soil temperature and photosynthetic active radiation, we have not yet identified a parameter that governs variations in methane exchange. Various environmental parameters appear to be related to methane emissions (including soil moisture, soil and air temperature and wind direction), but the scatter with respect to half hourly methane fluxes is too large to be useful for gap modeling. Analysis of daily averages reduces the scatter, but since methane exchange exhibits considerable daily variation, daily averages are not useful to fill data gaps of half hourly fluxes. In consequence, as the daily course is the summary result of all environmental parameters having influence on the methane exchange at the half-hour time scale of the measurements, the ensemble mean diurnal variation method over a suitable number of days is considered the most practical choice of gap filling method for methane fluxes at Schechenfilz site for estimating daily and annual sums. Overall, the annual CO2 uptake is estimated at a magnitude between -50 and -80 g C m-2 a-1, whereas the annual methane emissions are estimated to be about +6 g C m-2 a-1. Since N2O emissions can be neglected at natural peatland sites, the natural bog-pine ecosystem Schechenfilz is indicated to be a weak net sink of greenhouse gases in the past year, even if the higher global warming potential of methane is considered.

Hommeltenberg, Janina; Schmid, Hans Peter; Droesler, Matthias; Werle, Peter

2013-04-01

220

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

221

Snow Accumulation and Spring Melt Rates of Bogs and Fens in the North Granny Creek Catchment Basin, Hudson Bay Lowlands, Ontario  

NASA Astrophysics Data System (ADS)

The Hudson Bay Lowlands contain one of the most extensive, contiguous peatland complexes in the world. Interlinked patterned peatlands developed in this region because of the cool climate, low-gradient topography and an underlying layer of low conductivity marine sediments. There is currently little research regarding the mechanisms that control runoff and surface water connectivity in this region, especially the functions of different peatland types on runoff production and flow pathways. Runoff generation in these systems is dependent on several factors such as soil and pool storage capacity, snow accumulation and melt rates, and peatland morphometry. Snowmelt accounts for a major portion of total annual runoff in this region and the timing of the melt will determine effective runoff production from a peatland catchment. One of the objectives of this project is to identify the processes and mechanisms that generate spring snowmelt runoff in different peatland types (i.e. bogs and fens) and quantify the relative contribution of each type in a peatland-dominated catchment basin. This research is being conducted in a 30 km2 catchment basin located near the DeBeers Victor diamond mine, located 90 km west of Attawapiskat, Ontario. The North Granny Creek basin is located approximately 3 km from the mine pit and is comprised of several peatland types and forms. The surface hydrology of this area is expected to be affected by groundwater depressurization due to dewatering of the mine pit by deep groundwater pumping wells. Effects of this activity on surface hydrology could possibly include increased soil storage capacity due to drier conditions and decreased melt rates due to reduced inputs of warm groundwater. Surface water connectivity is usually at a maximum in the spring because of a relatively impermeable frost table and low soil storage capacity which reduces infiltration. These effects of melt will not be observed uniformly over the entire catchment because of the differing hydrological properties of peatland types. Fens are expected to experience melt quicker than bogs and will receive and convey most of the runoff waters. Snow survey data from the springs of 2008 and 2009 coupled with stream discharge measurements will be used to determine the characteristics of different peatland types that control snow accumulation, melt rates and runoff production and their respective contributions. Since it is expected that the surface hydrology of this area will change over time because of groundwater depressurization it is important to develop a base line characterization of runoff generation and flowpaths within and between peatland types. An examination of snow accumulation and melt characteristics is necessary in northern peatland complexes to fully understand the response of these environments to changes in hydrology.

Cook, C. F.; Price, J. S.

2009-05-01

222

Atmospheric controls on methane emissions from a subarctic bog in northern Quebec, Canada, using an open-path eddy covariance system  

NASA Astrophysics Data System (ADS)

Wetlands are the largest natural source of atmospheric methane, a powerful greenhouse gas. Over such environments, methane fluxes are traditionally quantified with static or dynamic chambers and gas chromatography. Although inexpensive and portable, this method does not allow for continuous measurements besides not capturing the effect of atmospheric turbulence on methane emissions. An alternative is closed-path eddy covariance systems, but these usually require high power consumption and regular maintenance, both of which are difficult to supply in highly remote areas where most Canadian wetlands are found. In this study we deployed the new open-path methane analyzer (model Li-7700) from Li-Cor inc. along with surface energy budget sensors over a 60-ha subarctic bog from June to September 2012. The field site (53.7°N, 78.2°W) is located near James Bay within the La Grande Rivière watershed. This work discusses the presence of diurnal patterns in turbulent methane fluxes, and analyzes the effect of atmospheric stability, turbulence intensity and other atmospheric controls on fluxes magnitude and timing. Methane emissions are also quantified at the daily scale and compared to previously reported values over similar sites with other methods. A more technical discussion is also included in which advantages, drawbacks and optimal setup configuration of the instrument are presented.

Rousseau, A. N.; Nadeau, D. F.; Parlange, M. B.; Coursolle, C.; Margolis, H. A.

2012-12-01

223

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

224

Anthropogenic impacts in North Poland over the last 1300 years--a record of Pb, Zn, Cu, Ni and S in an ombrotrophic peat bog.  

PubMed

Lead pollution history over Northern Poland was reconstructed for the last ca. 1300 years using the elemental and Pb isotope geochemistry of a dated Polish peat bog. The data show that Polish Pb-Zn ores and coal were the main sources of Pb, other heavy metals and S over Northern Poland up until the industrial revolution. After review of the potential mobility of each element, most of the historical interpretation was based on Pb and Pb isotopes, the other chemical elements (Zn, Cu, Ni, S) being considered secondary indicators of pollution. During the last century, leaded gasoline also contributed to anthropogenic Pb pollution over Poland. Coal and Pb-Zn ores, however, remained important sources of pollution in Eastern European countries during the last 50 years, as demonstrated by a high (206)Pb/(207)Pb ratio (1.153) relative to that of Western Europe (ca. 1.10). The Pb data for the last century were also in good agreement with modelled Pb inventories over Poland and the Baltic region. PMID:19683332

De Vleeschouwer, François; Fagel, Nathalie; Cheburkin, Andriy; Pazdur, Anna; Sikorski, Jaroslaw; Mattielli, Nadine; Renson, Virginie; Fialkiewicz, Barbara; Piotrowska, Natalia; Le Roux, Gaël

2009-10-15

225

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

226

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

Microsoft Academic Search

Paleoclimate reconstructions based on lipid biomarkers from peat bogs are relatively uncommon, although this approach has been widely applied to lake sediments where it yields histories of climate-related changes in types of vegetation and organic matter preservation. We describe stratigraphic patterns in peat lipid biomarker distributions extracted from a well-dated peat core from the Zoige-Hongyuan peat bog. The bog is

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

2006-01-01

227

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

228

Hydroxyapatite Deposition Disease.  

National Technical Information Service (NTIS)

Hydroxyapatite deposition disease (HADD), a disease most commonly found in middle-aged individuals, is characterized by deposition of calcium phosphate crystals in periarticular tissues. The deposits frequently occur in tendons near their osseous attachme...

D. P. Beall J. Q. Ly L. Folio S. J. Upton

2006-01-01

229

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

230

Uraniferous Phosphates: Resource, Security Risk, or Contaminant  

Microsoft Academic Search

The escalation of the price of uranium (U) yellow cake (summer high = $130\\/0.454 kg (lb) has called into question the continuing availability of sufficient stockpiles and ores to process. As was developed during the years following World War II, the establishment and maintenance of a strategic inventory is a reasonable consideration for today. Therefore, it becomes critical to look

D. V. LeMone; Ph. C. Goodell; S. G. Gibbs; J. W. Winston

2008-01-01

231

OZONIZATION OF CHATTANOOGA URANIFEROUS BLACK SHALE  

Microsoft Academic Search

Work on the oxidation of pyrite and organic matter of the shale by moist ; ozone is described. Information on the organic acids produced was obtained for ; possible industrial application. Pyrite was ozonized separately to es tablish ; its behavior uncomplicated by the presence of other constituents in the shale. ; In addition to iron sulfate salts and elemental

C. R. Kinney; J. T. Leonard

1961-01-01

232

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

233

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

PubMed Central

Background: In June 2008, burning peat deposits produced haze and air pollution far in excess of National Ambient Air Quality Standards, encroaching on rural communities of eastern North Carolina. Although the association of mortality and morbidity with exposure to urban air pollution is well established, the health effects associated with exposure to wildfire emissions are less well understood. Objective: We investigated the effects of exposure on cardiorespiratory outcomes in the population affected by the fire. Methods: We performed a population-based study using emergency department (ED) visits reported through the syndromic surveillance program NC DETECT (North Carolina Disease Event Tracking and Epidemiologic Collection Tool). We used aerosol optical depth measured by a satellite to determine a high-exposure window and distinguish counties most impacted by the dense smoke plume from surrounding referent counties. Poisson log-linear regression with a 5-day distributed lag was used to estimate changes in the cumulative relative risk (RR). Results: In the exposed counties, significant increases in cumulative RR for asthma [1.65 (95% confidence interval, 1.25–2.1)], chronic obstructive pulmonary disease [1.73 (1.06–2.83)], and pneumonia and acute bronchitis [1.59 (1.07–2.34)] were observed. ED visits associated with cardiopulmonary symptoms [1.23 (1.06–1.43)] and heart failure [1.37 (1.01–1.85)] were also significantly increased. Conclusions: Satellite data and syndromic surveillance were combined to assess the health impacts of wildfire smoke in rural counties with sparse air-quality monitoring. This is the first study to demonstrate both respiratory and cardiac effects after brief exposure to peat wildfire smoke.

Stone, Susan L.; Cascio, Wayne E.; Neas, Lucas M.; Kilaru, Vasu J.; Carraway, Martha Sue; Szykman, James J.; Ising, Amy; Cleve, William E.; Meredith, John T.; Vaughan-Batten, Heather; Deyneka, Lana; Devlin, Robert B.

2011-01-01

234

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

NASA Astrophysics Data System (ADS)

To compare the sensitivity of biomarker D/H ratios from two distinct climate archives, a lake and a peat bog on the Tropical Pacific Island of Terrania, compound-specific hydrogen isotope ratios (expressed as ?D values) were determined on lipid biomarkers from various biological sources deposited in the two climate archives. At present, Terrania or Washington Island (4°43`N, 160°25`W) permanently lies in the intertropical convergence zone (ITCZ) and receives an annual precipitation of 2,903 mm. The interior of this lens shaped island contains a freshwater lake and peat bogs. Previous studies on the lake sediments found evidence for a substantially drier climate at times during the Little Ice Age (AD 1400-1850) based on the lithologic transition from modern freshwater sediments to a sequence of pure cyanobacterial mat in concert with ?D values from total lipid extracts (Sachs et al., 2009). Here we report on ?D values from lipids of various sources: dinoflagellate algae (dinosterol and a saturated C30 sterol (4? -methyl-24-ethyl-5? -cholestan-3?-ol), microbial sources (diploptene and nC21 alkane) and higher plants (fern-7-ene, ?-sitosterol and stigmastanol). Mean ?D values from all lipids, measured in both archives, are significantly enriched in deuterium by between 22 and 86‰ during previously inferred drier climate conditions and simultaneously record the transition towards a freshwater lake at around AD1550. Measured ?D values of all lipids cover a wide range from -281‰ to -105‰ during freshwater deposition and from -185‰ to -50‰ when climate was drier. In agreement with the observed isotopic difference between lipids produced via the acetogenic and the mevalonic acid biosynthetic pathway ?D values for algae and higher plant sterols are depleted in deuterium relative to the nC21 alkane by 150‰ on average. The consistent ?D values from dinosterol and 4? -methyl-24-ethyl-5? -cholestan-3?-ol from the lake and peat deposits signify the robustness of these lipid ?D values to indicate hydrologic changes in the sedimentary record. ?D values among lipids of similar and disparate sources and/or biosynthetic origin from Washington Island lake (AD ~ 800-1550) and peat bog (AD~1200-1660) sediments are significantly enriched in deuterium prior to AD 1560/1640 and thus both suggest drier climate conditions resembling today’s environmental and depositional setting at Christmas Island which is located 300km SSE of Washington Island beyond the influence of the ITCZ.

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

2010-12-01

235

Novel interconnect deposition technology  

NASA Astrophysics Data System (ADS)

A new series of experiments was initiated to improve current interconnect deposition technology for integrated circuits. Preliminary aluminum deposition experiments were carried out using trimethylamine(alane) as the precursor, and some mildly reflective, uniform aluminum films were successfully deposited on glass slides, suggesting that chemical vapor deposition (CVD) will be a practicable deposition technique for advanced integrated circuit interconnect films. CVD studies of aluminum and zirconium- and hafnium-diboride thin films are continuing.

Speckman, D. M.; Wendt, J. P.

1991-12-01

236

The impact of drain blocking on an upland blanket bog during storm and drought events, and the importance of sampling-scale  

NASA Astrophysics Data System (ADS)

SummaryOrganic carbon solution and transport processes which occur during periods of heavy rainfall and periods or little or no rainfall, can exert a significant control over a systems' annual organic carbon budget. In addition, either or both extremes can be key contributors to contaminant release, water discolouration, flood risk or vegetation growth. Although there is an increasing body of work studying hydrological responses to peatland restoration, there are very little available data on the performance of restored peatlands during these key periods. This study builds on previous work from an upland peatland in Wales that has been restored through drain-blocking, and presents evidence from a landscape scale experimental study at the site. A comparison of sampling scales within the study demonstrates the necessity of larger spatial scales, in combination with high resolution datasets, in assessing catchment level responses. Our results suggest that drain blocking leads to higher and more stable water tables that are able to better resist drought periods, and thus lead to more stable discharge from the system. The shallower water tables and pooling in drains also appear to reduce the production and transport of fluvial organic carbon, and thus less organic material is available to be released as during peak flow or dry periods. Despite restoration apparently reducing the available water storage within the peat, the increase in overland flow and in pooling within blocked drains appears to have led to a less flashy system. Peak flow responses in both drains and upland streams are less severe, with more rainfall being retained within the bog. We suggest that restoration leads to a more buffered system, with more moderate responses to extreme events, and reduced release of both dissolved and particulate organic carbon. We discuss the implications of this for fluxes of fluvial organic carbon and sediment loss.

Wilson, Lorraine; Wilson, Jared; Holden, Joseph; Johnstone, Ian; Armstrong, Alona; Morris, Michael

2011-07-01

237

The effects of ecological restoration, on soil-pore water quality and DOC concentrations, on a British upland blanket bog.  

NASA Astrophysics Data System (ADS)

Polluted by past atmospheric deposition, eroded and burnt, the Bleaklow plateau (Peak district National Park, UK) has long been degraded. Peatlands are important carbon reservoirs and can act as sources or sinks of carbon. Dissolved organic carbon (DOC) is carbon lost from peatlands via the fluvial pathway and as the major component of water colour it is costly to remove during water treatment processes. The Bleaklow Summit peatlands, were subjected to a large wildfire in 2003 devegetating 5.5km2. This fire prompted stakeholders to initiate a large-scale programme of restoration of the plateau. This study considered restoration techniques across four sites: all four sites were seeded with lawn grass, limed and fertilised; to raise the pH and allow establishment of vegetation. In addition to these interventions, one site also had a mulch of Calluna vulgaris applied to the surface to allow soil stabilisation and promote vegetation establishment and another site had biodegradable geojute textile mesh installed, to stabilize the steep gully surfaces. Another site had a gully block installed, to reduce peat desiccation and erosion. This study will compare the four restored sites to two types of comparators: bare soil sites where no restoration was undertaken and a naturally vegetated site unaffected by the 2003 wildfire. Each site had six replicate dipwells, installed in two groups of three. The depth to the water table was monitored and soil water samples collected for analysis, monthly for 5 years, from Nov 2006 - Jan 2012. No significant difference in DOC concentration was found between control and treated sites. There was, however, a significant difference in DOC composition between sites and over the 5 year period of monitoring. UV-vis absorbance of the samples is used to quantify the fulvic to humic components of DOC. The vegetated control was not significantly different to the bare sites; however the vegetated control had a significantly greater humic fraction of than the seeded, limed and fertilised only site, as well as the seeded, limed, C. vulgaris mulched site. This is possibly related to vegetation and litter layer establishment. A suite of water quality data (conductivity, pH and cation data) are now being analysed in combination with DOC to increase understanding of the relationship between bare site re-vegetation and DOC compositional change.

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

2013-04-01

238

DRY DEPOSITION MODULE FOR REGIONAL ACID DEPOSITION  

EPA Science Inventory

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

239

Sampling Tsunami Deposits  

USGS Multimedia Gallery

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

240

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

NASA Astrophysics Data System (ADS)

Climate change affects many natural processes and the same applies to human impact For instance climate change and anthropogenic activities may cause increased fire activity or change peatland dynamics. Currently it is still unknown how Sphagnum peatlands in the oceanic-continental transition zone of Poland may respond to combined effects of heat waves, drought and fire. The aim of the study was to reconstruct the last 2000 years palaeohydrology and fire history at Linje bog in Northern Poland. The main task was to determine the drivers of fire episodes, particularly to identify climatic and anthropogenic forcing. A two-meter peat core was extracted and subsampled with a high resolution. Micro- and macroscopic charcoal analyses were applied to determine past fire activity and the results compared with palaeohydrological reconstructions based on testate amoeba analysis. Palynological human indicators were used to reconstruct human activity. A depth-age model including 20 14C dates was constructed to calculate peat accumulation rates and charcoal influx. We hypothesised that: 1) fire frequency in Northern Poland was determined by climatic conditions (combination of low precipitation and heat waves), as reflected in peatland water table, and that 2) past fire episodes in the last millennium were intensified by human activity. Furthermore climate may have influenced human activity over harvest success and the carrying capacity. Our study shows that fire was important for the studied ecosystem, however, its frequency has increased in the last millennium in concomitance with land use activities. Landscape humanization and vegetation opening were followed by a peatland drying during the Little Ice Age (from ca. AD 1380). Similarly to other palaeoecological studies from Poland, Linje peatland possessed an unstable hydrology during the Little Ice Age. Increased fire episodes appeared shortly before the Little Ice Age and most severe fires were present in the time when recorded water table was the lowest. We acknowledge the support of RE-FIRE SCIEX project 12.286 and grant PSPB-013/2010 from Switzerland through the Swiss Contribution to the enlarged European Union.

Marcisz, Katarzyna; Tinner, Willy; Colombaroli, Daniele; Ko?aczek, Piotr; S?owi?ski, Micha?; Fia?kiewicz-Kozie?, Barbara; Lamentowicz, Mariusz

2014-05-01

241

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

242

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

243

Preliminary Classification of Uranium Deposits.  

National Technical Information Service (NTIS)

For this classification, uranium deposits in sedimentary rocks are divided into two groups, syngenetic and epigenetic: syngenetic deposits are formed contemporaneously with deposition of the enclosing sediment; while epigenetic deposits are formed by prec...

D. G. Mickle

1978-01-01

244

Exploring for Copper Deposits  

NSDL National Science Digital Library

In this activity, students assume the role of a geologist prospecting for copper deposits. From the background material, they will learn what ore deposits are and some important factors in their origin; and learn about a type of ore deposit known as a porphyry copper deposit. They will plot data from a table onto maps and use a geologic map, a soil geochemistry map, and a sediment geochemistry map to help locate the porphyry copper deposit. As a result of this activity, the students will be able to calculate an ore grade and determine whether or not an ore deposit is economically profitable based on its grade, size, and production costs. Worksheets and data tables are included.

245

Deposition Measurements in NSTX  

NASA Astrophysics Data System (ADS)

Two quartz microbalances have been used to record deposition on the National Spherical Torus Experiment. The experimental configuration mimics a typical diagnostic window or mirror. An RS232 link was used to acquire the quartz crystal frequency and the deposited thickness was recorded continuously with 0.01 nm resolution. Nuclear Reaction Analysis of the deposit was consistent with the measurement of the total deposited mass from the change in crystal frequency. We will present measurements of the variation of deposition with plasma conditions. The transport of carbon impurities in NSTX has been modelled with the BBQ code. Preliminary calculations indicated a negligible fraction of carbon generated at the divertor plates in quiescent discharges directly reaches the outer wall, and that transient events are responsible for the deposition.

Skinner, C. H.; Kugel, H. W.; Hogan, J. T.; Wampler, W. R.

2004-11-01

246

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

NASA Astrophysics Data System (ADS)

Anthropogenic drainage of peatlands releases additional greenhouse gases to the atmosphere, and dissolved carbon (C) and nutrients to downstream ecosystems. Rewetting drained peatlands offers a possibility to reduce nitrogen (N) and C losses. In this study, we investigate the impact of drainage and rewetting on the cycling of dissolved C and N as well as on dissolved gases, over a period of 1 year and a period of 4 months. We chose four sites within one Atlantic bog complex: a near-natural site, two drained grasslands with different mean groundwater levels and a former peat cutting area rewetted 10 years ago. Our results clearly indicate that long-term drainage has increased the concentrations of dissolved organic carbon (DOC), ammonium, nitrate and dissolved organic nitrogen (DON) compared to the near-natural site. DON and ammonium contributed the most to the total dissolved nitrogen. Nitrate concentrations below the mean groundwater table were negligible. The concentrations of DOC and N species increased with drainage depth. In the deeply-drained grassland, with a mean annual water table of 45 cm below surface, DOC concentrations were twice as high as in the partially rewetted grassland with a mean annual water table of 28 cm below surface. The deeply drained grassland had some of the highest-ever observed DOC concentrations of 195.8 ± 77.3 mg L-1 with maximum values of >400 mg L-1. In general, dissolved organic matter (DOM) at the drained sites was enriched in aromatic moieties and showed a higher degradation status (lower DOC to DON ratio) compared to the near-natural site. At the drained sites, the C to N ratios of the uppermost peat layer were the same as of DOM in the peat profile. This suggests that the uppermost degraded peat layer is the main source of DOM. Nearly constant DOM quality through the profile furthermore indicated that DOM moving downwards through the drained sites remained largely biogeochemically unchanged. Unlike DOM concentration, DOM quality and dissolved N species distribution were similar in the two grasslands and thus unaffected by the drainage depth. Methane production during the winter months at the drained sites was limited to the subsoil, which was quasi-permanently water saturated. The recovery of the water table in the winter months led to the production of nitrous oxide around mean water table depth at the drained sites. The rewetted and the near-natural site had comparable DOM quantity and quality (DOC to DON ratio and aromaticity). 10 years after rewetting quasi-pristine biogeochemical conditions have been re-established under continuously water logged conditions in the former peat cut area. Only the elevated dissolved methane and ammonium concentrations reflected the former disturbance by drainage and peat extraction. Rewetting via polder technique seems to be an appropriate way to revitalize peatlands on longer timescales and to improve the water quality of downstream water bodies.

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

2014-04-01

247

Deposition times in the northeastern United States during the Holocene: establishing valid priors for Bayesian age models  

NASA Astrophysics Data System (ADS)

Age-depth relationships in sedimentary archives such as lakes, wetlands and bogs are non-linear with irregular probability distributions associated with calibrated radiocarbon dates. Bayesian approaches are thus well-suited to understanding relationships between age and depth for use in paleoecological studies. Bayesian models for the accumulation of sediment and organic matter within basins combine dated material from one or more records with prior information about the behavior of deposition times (yr/cm) based on expert knowledge. Well-informed priors are essential to good modeling of the age-depth relationship, but are particularly important in cases where data may be sparse (e.g., few radiocarbon dates), or unclear (e.g., age-reversals, coincident dates, age offsets, outliers and dates within a radiocarbon plateau). Here we assessed Holocene deposition times using 204 age-depth models obtained from the Neotoma Paleoecology Database (www.neotomadb.org) for both lacustrine and palustrine environments across the northeastern United States. These age-depth models were augmented using biostratigraphic events identifiable within pollen records from the northeastern United States during the Holocene and late-Pleistocene. Deposition times are significantly related to depositional environment (palustrine and lacustrine), sediment age, and sediment depth. Spatial variables had non-significant relationships with deposition time when site effects were considered. The best-fit model was a generalized additive mixed model that relates deposition time to age, stratified by depositional environment with site as a random factor. The best-fit model accounts for 63.3% of the total deviance in deposition times. The strongly increasing accumulation rates of the last 500-1000 years indicate that gamma distributions describing lacustrine deposition times (? = 1.08, ? = 18.28) and palustrine deposition times (? = 1.23, ? = 22.32) for the entire Holocene may be insufficient for Bayesian approaches since there is strong variation in the gamma parameters both in the most recent sediments and throughout the Holocene. Time-averaged gamma distributions for lacustrine (? = 1.35, ? = 19.64) and palustrine samples (? = 1.40, ? = 20.72) show lower overall deposition times, but variability remains. The variation in gamma parameters through time may require the use of multiple gamma distributions during the Holocene to generate accurate age-depth models. We present estimates of gamma parameters for deposition times at 1000 yr intervals. The parameters generated in this study can be used directly within Bacon to act as Bayesian priors for sedimentary age models.

Goring, S.; Williams, J. W.; Blois, J. L.; Jackson, S. T.; Paciorek, C. J.; Booth, R. K.; Marlon, J. R.; Blaauw, M.; Christen, J. A.

2012-08-01

248

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

249

The Deposition Process  

NSDL National Science Digital Library

This website includes an animation of the chemical vapor deposition process. Objective: Identify the process of chemical vapor deposition. This simulation is from Module 054 of the Process & Equipment I Cluster of the MATEC Module Library (MML). To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey

2012-11-08

250

Chemical Vapor Deposition Growth.  

National Technical Information Service (NTIS)

A chemical vapor deposition (CVD) reactor system with a vertical deposition chamber was used for the growth of Si films on glass, glass-ceramic, and polycrystalline ceramic substrates. Silicon vapor was produced by pyrolysis of SiH4 in a H2 or He carrier ...

R. P. Ruth, H. M. Manasevit, J. L. Kenty, L. A. Moudy, W. I. Simpson

1976-01-01

251

Carbamate deposit control additives  

SciTech Connect

Deposit control additives for internal combustion engines are provided which maintain cleanliness of intake systems without contributing to combustion chamber deposits. The additives are poly(oxyalkylene) carbamates comprising a hydrocarbyloxyterminated poly(Oxyalkylene) chain of 2-5 carbon oxyalkylene units bonded through an oxycarbonyl group to a nitrogen atom of ethylenediamine.

Honnen, L.R.; Lewis, R.A.

1980-11-25

252

Electroless Palladium Deposition.  

National Technical Information Service (NTIS)

Electroless deposition of palladium was achieved from solutions utilizing hypophosphite as reducing agent at temperatures from 30 to 70C. Electroless palladium deposits contain about 1.5 per cent phosphorus and have a Vickers hardness of about 165 kg/sq m...

F. Pearlstein R. F. Weightman

1969-01-01

253

Stratiform chromite deposit model  

USGS Publications Warehouse

Stratiform chromite deposits are of great economic importance, yet their origin and evolution remain highly debated. Layered igneous intrusions such as the Bushveld, Great Dyke, Kemi, and Stillwater Complexes, provide opportunities for studying magmatic differentiation processes and assimilation within the crust, as well as related ore-deposit formation. Chromite-rich seams within layered intrusions host the majority of the world's chromium reserves and may contain significant platinum-group-element (PGE) mineralization. This model of stratiform chromite deposits is part of an effort by the U.S. Geological Survey's Mineral Resources Program to update existing models and develop new descriptive mineral deposit models to supplement previously published models for use in mineral-resource and mineral-environmental assessments. The model focuses on features that may be common to all stratiform chromite deposits as a way to gain insight into the processes that gave rise to their emplacement and to the significant economic resources contained in them.

Schulte, Ruth F.; Taylor, Ryan D.; Piatak, Nadine M.; Seal, Robert R. II

2010-01-01

254

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

255

The effect of particulate organic carbon deposition (POC) on the gaseous carbon budget of a floodplain in an actively eroding peatland.  

NASA Astrophysics Data System (ADS)

In actively eroding peatlands, particulate carbon losses can be very large, with the potential to shift peatland systems from carbon sinks to carbon sources. POC is potentially converted to gaseous forms by direct oxidation from depositional sites such as floodplains. Incorporation of these processes into carbon budgets is problematic as direct measurements are lacking. This paper presents data from a field experiment designed to evaluate the importance of floodplain environments in 'processing' POC derived from eroded blanket peatlands. 24 gas collars were installed on a floodplain in the highly eroded Upper North Grain research catchment in the South Pennines, UK. Measurements were made at fortnightly intervals over a 12 month period to ascertain the CO2 flux from an unmodified floodplain surface, a floodplain surface covered by a 20 mm particulate organic matter (POM) layer, and a 20 mm POM layer isolated from the soil surface. Results show that POC deposition onto floodplains leads to CO2 emission via oxidation of the deposited material, and suppresses photosynthesis due to burial of floodplain vegetation. POC deposited on the floodplains was oxidised at a rate of around 1.6-3.8 %/yr, implying that it will remain an active CO2 source for around 30 years. An annual carbon loss budget of the system estimates carbon losses from the floodplain surface of 528-598 gC/m2/yr, which exceed typical carbon fixation by active blanket bogs by an order of magnitude.

Goulsbra, Claire; Evans, Martin; Allott, Tim; Rowson, James; Evans, Chris

2014-05-01

256

EDITORIAL: Atomic layer deposition Atomic layer deposition  

NASA Astrophysics Data System (ADS)

The growth method of atomic layer deposition (ALD) was introduced in Finland by Suntola under the name of atomic layer epitaxy (ALE). The method was originally used for deposition of thin films of sulphides (ZnS, CaS, SrS) activated with manganese or rare-earth ions. Such films were grown for applications in thin-film electroluminescence (TFEL) displays. The ALE mode of growth was also tested in the case of molecular beam epitaxy. Films grown by ALD are commonly polycrystalline or even amorphous. Thus, the name ALE has been replaced by ALD. In the 80s ALD was developed mostly in Finland and neighboring Baltic countries. Deposition of a range of different materials was demonstrated at that time, including II-VI semiconductors (e.g. CdTe, CdS) and III-V (e.g. GaAs, GaN), with possible applications in e.g. photovoltaics. The number of publications on ALD was slowly increasing, approaching about 100 each year. A real boom in interest came with the development of deposition methods of thin films of high-k dielectrics. This research was motivated by a high leakage current in field-effect transistors with SiO2-based gate dielectrics. In 2007 Intel introduced a new generation of integrated circuits (ICs) with thin films of HfO2 used as gate isolating layers. In these and subsequent ICs, films of HfO2 are deposited by the ALD method. This is due to their unique properties. The introduction of ALD to the electronics industry led to a booming interest in the ALD growth method, with the number of publications increasing rapidly to well above 1000 each year. A number of new applications were proposed, as reflected in this special issue of Semiconductor Science and Technology. The included articles cover a wide range of possible applications—in microelectronics, transparent electronics, optoelectronics, photovoltaics and spintronics. Research papers and reviews on the basics of ALD growth are also included, reflecting a growing interest in precursor chemistry and growth processes. Summarizing, this special issue of Semiconductor Science and Technology reflects the rapidly growing interest in the ALD growth method and demonstrates the wide range of possible practical applications of ALD-grown materials, not only of high-k dielectrics, but also of a range of different materials (e.g. ZnO). Finally, I would like to thank the IOP editorial staff, in particular Alice Malhador, for their support and efforts in making this special issue possible.

Godlewski, Marek

2012-07-01

257

Ion Deposited Carbon Coatings.  

National Technical Information Service (NTIS)

The overall objective of this program is to demonstrate a system capable of reproducibly coating polycarbonate plastic sheet with ion deposited transparent carbon. The carbon coatings are to be characterized on the plastic sheet for potential use as a dur...

S. Aisenberg M. Stein

1983-01-01

258

Electrospark Deposition Coatings.  

National Technical Information Service (NTIS)

Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or...

W. F. Sheely

1986-01-01

259

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 ...

260

World oil shale deposits  

SciTech Connect

The article estimates resources in-place and their oil equivalent. The major deposits are described in the U.S., Australia, USSR, Peoples Republic of China, Morocco, Israel, Jordan, Syria, Europe and South America. 2 refs.

Hook, C.O.; Russell, P.L.

1982-01-01

261

Plasma Deposition of Tungsten.  

National Technical Information Service (NTIS)

Tungsten films were plasma-deposited using an abnormal glow discharge through a mixture of tungsten hexafluoride, hydrogen, and argon. The films adhered well to silicon, silicon dioxide, gallium arsenide, and aluminum substrates placed directly on the dis...

K. E. Greenberg

1986-01-01

262

Chemical vapor deposition growth  

NASA Technical Reports Server (NTRS)

A chemical vapor deposition (CVD) reactor system with a vertical deposition chamber was used for the growth of Si films on glass, glass-ceramic, and polycrystalline ceramic substrates. Silicon vapor was produced by pyrolysis of SiH4 in a H2 or He carrier gas. Preliminary deposition experiments with two of the available glasses were not encouraging. Moderately encouraging results, however, were obtained with fired polycrystalline alumina substrates, which were used for Si deposition at temperatures above 1,000 C. The surfaces of both the substrates and the films were characterized by X-ray diffraction, reflection electron diffraction, scanning electron microscopy optical microscopy, and surface profilometric techniques. Several experiments were conducted to establish baseline performance data for the reactor system, including temperature distributions on the sample pedestal, effects of carrier gas flow rate on temperature and film thickness, and Si film growth rate as a function of temperature.

Ruth, R. P.; Manasevit, H. M.; Kenty, J. L.; Moudy, L. A.; Simpson, W. I.; Yang, J. J.

1976-01-01

263

Chemical Vapor Deposition Growth.  

National Technical Information Service (NTIS)

A laboratory type CVD reactor system with a vertical deposition chamber and sample pedestal heated by an external RF coil has been extensively modified by installation of mass flow controllers, automatic process sequence timers, and special bellows-sealed...

R. P. Ruth, H. M. Manasevit, R. E. Johnson, J. L. Kenty, L. A. Moudy

1976-01-01

264

Stratiform Chromite Deposit Model.  

National Technical Information Service (NTIS)

Stratiform chromite deposits are of great economic importance, yet their origin and evolution remain highly debated. Layered igneous intrusions such as the Bushveld, Great Dyke, Kemi, and Stillwater Complexes, provide opportunities for studying magmatic d...

N. M. Piatak R. D. Taylor R. F. Schulte R. R. Seal

2010-01-01

265

Electrospark deposition coatings  

NASA Astrophysics Data System (ADS)

Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life.

Sheely, W. F.

1986-11-01

266

Nanoclusters deposited on surfaces  

Microsoft Academic Search

Recently, films produced by depositing pre-formed mass-selected atomic clusters in the size range 1–10nm have generated a great deal of attention. The ability to control the size, density and in some cases the morphology of the deposited particles allows unprecedented flexibility in the creation of new types of nanostructure. The technique enables research on the fundamental behaviour of matter at

C. Binns

2001-01-01

267

Convective microsphere monolayer deposition  

NASA Astrophysics Data System (ADS)

There is perhaps no simpler way of modifying surface chemistry and morphology than surface deposition of particles. Micron-sized microspheres were deposited into thin films via rapid convective deposition, similar to the `coffee ring effect' using a similar method to that studied by Prevo and Velev, Langmuir, 2003. By varying deposition rate and blade angle, the optimal operating ranges in which 2D close-packed arrays of microspheres existed were obtained. Self-assembly of colloidal particles through a balance of electrostatic and capillary forces during solvent evaporation was revealed. These interactions were explored through a model comparing the residence time of a particle in the thin film and the characteristic time of capillary-driven crystallization to describe the morphology and microstructure of deposited particles. Co-deposition of binary suspensions of micron and nanoscale particles was tailored to generate higher-quality surface coatings and a simple theory describes the immergence of instabilities that result in formation of stripes. Optical and biomedical applications that utilize the described nanoscale control over surface morphology will also be discussed.

Gilchrist, James

2011-03-01

268

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

269

Pulsed laser deposition: Prospects for commercial deposition of epitaxial films  

SciTech Connect

Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique for the deposition of thin films. The vapor source is induced by the flash evaporation that occurs when a laser pulse of sufficient intensity (about 100 MW/cm{sup 2}) is absorbed by a target. In this paper the author briefly defines pulsed laser deposition, current applications, research directed at gaining a better understanding of the pulsed laser deposition process, and suggests some future directions to enable commercial applications.

Muenchausen, R.E.

1999-03-01

270

Bog bilberry (Vaccinium uliginosum L.) extract reduces cultured Hep-G2, Caco-2, and 3T3-L1 cell viability, affects cell cycle progression, and has variable effects on membrane permeability.  

PubMed

Bog bilberry (Vaccinium uliginosum L.) is a blue-pigmented edible berry related to bilberry (Vaccinium myrtillus L.) and the common blueberry (Vaccinium corymbosum). The objective of this study was to investigate the effect of a bog bilberry anthocyanin extract (BBAE) on cell growth, membrane permeability, and cell cycle of 2 malignant cancer cell lines, Caco-2 and Hep-G2, and a nonmalignant murine 3T3-L1 cell line. BBAE contained 3 identified anthocyanins. The most abundant anthocyanin was cyanidin-3-glucoside (140.9 +/- 2.6 microg/mg of dry weight), followed by malvidin-3-glucoside (10.3 +/- 0.3 microg/mg) and malvidin-3-galactoside (8.1 +/- 0.4 microg/mg). Hep-G2 LC50 was calculated to be 0.563 +/- 0.04 mg/mL, Caco-2 LC50 was 0.390 +/- 0.30 mg/mL and 0.214 +/- 0.02 mg/mL for 3T3-L1 cells. LDH release, a marker of membrane permeability, was significantly increased in Hep-G2 cells and Caco-2 cells after 48 and 72 h compared to 24 h. The increase was 21% at 48 h and 57% at 72 h in Caco-2 cells and 66% and 139% in Hep-G2 cells compared to 24 h. However, 3T3-L1 cells showed an unexpected significant lower LDH activity (P < or = 0.05) after 72 h of exposure corresponding to a 21% reduction in LDH release. BBAE treatment increased sub-G1 in all 3 cell lines without influencing cells in the G2/M phase. BBAE treatment reduced the growth and increased the accumulation of sub-G1 cells in 2 malignant and 1 nonmalignant cell line; however, the effect on membrane permeability differs considerably between the malignant and nonmalignant cells and may in part be due to differences in cellular membrane composition. PMID:20492295

Liu, Jia; Zhang, Wei; Jing, Hao; Popovich, David G

2010-04-01

271

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...

272

Electrostatic Deposition of Graphene  

Microsoft Academic Search

Loose graphene sheets, one to a few atomic layers thick are often observed on freshly cleaved HOPG surfaces. A simple and reliable technique using electrostatic attraction is demonstrated to transfer these graphene sheets to a selected substrate. Sheets from one to 22 layers thick have been transferred by this method. One sheet after initial deposition is measured by atomic force

Anton N Sidorov; Gamini Sumanasekera; Mehdi Yazdanpanah; Romaneh Jalilian; P. Ouseph; Robert Cohn

2007-01-01

273

MODELED WET NITRATE DEPOSITION  

EPA Science Inventory

Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface water bodies. See below regarding decriptions on how original data was produced. These data will be part of futur...

274

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

275

Nanoparticle Deposition onto Biofilms  

PubMed Central

We develop a mathematical model of nanoparticles depositing onto and penetrating into a biofilm grown in a parallel-plate flow cell. We carry out deposition experiments in a flow cell to support the modeling. The modeling and the experiments are motivated by the potential use of polymer nanoparticles as part of a treatment strategy for killing biofilms infecting the deep passages in the lungs. In the experiments and model, a fluid carrying polymer nanoparticles is injected into a parallel-plate flow cell in which a biofilm has grown over the bottom plate. The model consists of a system of transport equations describing the deposition and diffusion of nanoparticles. Standard asymptotic techniques that exploit the aspect ratio of the flow cell are applied to reduce the model to two coupled partial differential equations. We perform numerical simulations using the reduced model. We compare the experimental observations with the simulation results to estimate the nanoparticle sticking coefficient and the diffusion coefficient of the nanoparticles in the biofilm. The distributions of nanoparticles through the thickness of the biofilm are consistent with diffusive transport, and uniform distributions through the thickness are achieved in about four hours. Nanoparticle deposition does not appear to be strongly influenced by the flow rate in the cell for the low flow rates considered.

Miller, J.K.; Neubig, R.; Clemons, C.B.; Kreider, K.L.; Wilber, J.P.; Young, G.W.; Ditto, A.J.; Yun, Y.H.; Milsted, A.; Badawy, H.T.; Panzner, M.J.; Youngs, W.J.; Cannon, C.L.

2012-01-01

276

Deposit Market Deregulation, Implicit Deposit Rates, and Monetary Policy.  

National Technical Information Service (NTIS)

A model of oligopolistic rivalry in bank deposit markets is used to consider the implications of deposit rule deregulation and increased bank competition for bank behavior, financial market outcomes, and monetary policy. In the context of this model, it i...

D. D. VanHoose

1987-01-01

277

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

278

Injector deposits - The tip of intake system deposit problems  

Microsoft Academic Search

A comprehensive program encompassing laboratory engine, laboratory vehicle, and taxi fleet tests was undertaken to evaluate fuel variables and induction system deposits in modern spark-ignition engines. The widespread fuel injector deposit problem was the primary focus. Injector and vehicle design, driving cycle, and fuel composition were found to be major contributing factors to injector deposition. Commercial gasoline additives capable of

B. Y. Taniguchi; R. J. Peyla; G. M. Parsons; S. K. Hoekman; D. A. Voss

1986-01-01

279

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

280

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...

281

Geochronology, based on pollen and isotopes, of a Late Glacial gyttja deposit in Vorarlberg, Austria  

NASA Astrophysics Data System (ADS)

Geochronology, based on pollen and isotopes, of a Late Glacial gyttja deposit in Vorarlberg, Austria. The Gasserplatz, a peat biotope with histosols, is situated 1 km NE of Feldkirch in Vorarlberg. During the last deglaciation, i.e. the retreat of the Ill glacier by the end of the Oldest Dryas, a tiny ice-marginal lake here developed in a sheltered position at an elevation of 439 m.a.s. After local deglaciation, lacustrine carbonate (chalk gyttja) deposited. At the beginning of the Holocene the lake changed into a peat bog with peat accumulation. The soil archive of the Gasserplatz contains a 6m undisturbed high quality paleoecological record, a sequence of Late Glacial and Holocene deposits. To ‘read' this record we applied pollen and isotope analysis on the Late Glacial lacustrine carbonate deposits. Research on the Gasserplatz profile will be continued by pollen analysis and radiocarbon dating of the Holocene peat deposits. The sedimentation in the former lake started with sterile clay deposition (70 cm) on till. Around 13,000 BP (radiocarbon years) deposition of a 270 cm lacustrine carbonate section started. The deposition rate was rather constant, about 0.85mm per year during almost 3000 years. Peat accumulation started at around 9,500 BP. The pollen diagram of the lake marl deposits shows the vegetation development starting at 13,000 BP. The oldest spectra (535-500 cm) reflect a pioneer vegetation (Artemisia, Helianthemum, Gramineae), followed by invasions of Betula, Juniperus and Pinus. Oscillations in Betula percentages are probably caused by temperature variations. 14C dating of the lake marl deposits is not straightforward. Depending on the source materials (shale's, organic mud, peat) we found different ages at the same depth in the core. Shale's and fibric peat provide the best results for a correct geochronology of the record. ?13C variations show (1) periods without and with biomass production, and (2) qualitative properties of produced biomass. Both are related to temperature. Due to the low concentration of C atoms in water, ? 13C values are very sensitive for system changes. In polar ice cores, d18O variations reflect directly changes in the composition of precipitation, which is a proxy for climatic change. In lacustrine carbonate sediments the d18O values are influenced also by factors like evaporation and lake feeding drain water from the surroundings, but in general the trend in the d18O curve can be correlated with trends in ice cores. Oscillations in the pollen curves (e.g. Betula) and isotope curves of the Gasserplatz core can be correlated. The d18O oscillations of the Gasserplatz core correlate with the polar ice core oscillations and can be used to derive a correct geochronology of the lacustrine carbonate deposits. As a consequence, both pollen and isotopic analysis can be used to reconstruct the evolution of the lake system.

van Mourik, J. M.; Slotboom, R. T.; Streurman, H. J.; van der Plicht, J.; de Graaff, L. W. S.

2009-04-01

282

Electrophoretic deposition of biomaterials.  

PubMed

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

2010-10-01

283

Uranium deposits of Brazil  

SciTech Connect

Brazil is a country of vast natural resources, including numerous uranium deposits. In support of the country`s nuclear power program, Brazil has developed the most active uranium industry in South America. Brazil has one operating reactor (Angra 1, a 626-MWe PWR), and two under construction. The country`s economic challenges have slowed the progress of its nuclear program. At present, the Pocos de Caldas district is the only active uranium production. In 1990, the Cercado open-pit mine produced approximately 45 metric tons (MT) U{sub 3}O{sub 8} (100 thousand pounds). Brazil`s state-owned uranium production and processing company, Uranio do Brasil, announced it has decided to begin shifting its production from the high-cost and nearly depleted deposits at Pocos de Caldas, to lower-cost reserves at Lagoa Real. Production at Lagoa Real is schedules to begin by 1993. In addition to these two districts, Brazil has many other known uranium deposits, and as a whole, it is estimated that Brazil has over 275,000 MT U{sub 3}O{sub 8} (600 million pounds U{sub 3}O{sub 8}) in reserves.

NONE

1991-09-01

284

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

285

Thin film deposition with physical vapor deposition and related technologies  

NASA Astrophysics Data System (ADS)

The properties of thin films depend critically on how they are made. For the most part, thin films are assembled in ways very different from the production of bulk materials. Thin films are usually deposited on existing, bulk surfaces using techniques based on atomic or molecular scale physics and chemistry. Physical vapor deposition (PVD) of thin films relies on the removal of atoms from a solid or a liquid by energetic means, and the subsequent deposition of those atoms on a nearby surface. Variations of PVD processes include thermal evaporation, physical sputtering, laser ablation, and arc-based emission. Additional modifications to physical sputter deposition have been made to enhance the chemical and/or structural nature of the deposited films. These modifications include reactive sputter deposition, the unbalanced magnetron, collimated and ionized sputter deposition. Each of these systems and techniques will be described as well as some of the current day applications of the films produced.

Rossnagel, S. M.

2003-09-01

286

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

287

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

288

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

289

Electrophoretic Deposition for Fabricating Microbatteries  

NASA Technical Reports Server (NTRS)

An improved method of fabrication of cathodes of microbatteries is based on electrophoretic deposition. Heretofore, sputtering (for deposition) and the use of photoresist and liftoff (for patterning) have been the primary methods of fabricating components of microbatteries. The volume of active electrode material that can be deposited by sputtering is limited, and the discharge capacities of prior microbatteries have been limited accordingly. In addition, sputter deposition is slow. In contrast, electrophoretic deposition is much faster and has shown promise for increasing discharge capacities by a factor of 10, relative to those of microbatteries fabricated by prior methods.

West, William; Whitacre, Jay; Bugga, Ratnakumar

2003-01-01

290

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

291

Fluidized Crater Ejecta Deposit  

NASA Technical Reports Server (NTRS)

The Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) spacecraft continued to obtain high resolution images of the red planet into August 1998. At this time, each ground track (the portion of Mars available for MOC imaging on a given orbit) covers areas from about 40oN on the late afternoon side of the planet, up over the sunlit north polar cap, and down the early morning side of Mars to about 20oN latitude. Early morning and late afternoon views provide good shadowing to reveal subtle details on the martian surface. Views of Mars with such excellent lighting conditions will not be seen by MOC once MGS's Science Phasing Orbits end in mid-September 1998.

The image shown here, MOC image 47903, was targeted on Friday afternoon (PDT), August 7, 1998. This picture of ejecta from a nameless 9.1 kilometer (5.7 mile)-diameter crater was designed to take full advantage of the present lighting conditions. When the image was taken (around 5:38 p.m. (PDT) on Saturday, August 8, 1998), the Sun had just risen and was only about 6o above the eastern horizon. With the Sun so low in the local sky, the contrast between sunlit and shadowed surfaces allowed new, subtle details to be revealed on the surface of the crater ejecta deposit.

The crater shown here has ejecta of a type that was first identified in Mariner 9 and Viking Orbiter images as 'fluidized' ejecta. Ejecta is the material that is thrown out from the crater during the explosion that results when a meteor--piece of a comet or asteroid--collides with the planet. Fluidized ejecta is characterized by its lobate appearance, and sometimes by the presence of a ridge along the margin of the ejecta deposit. In the case of the crater shown here, there are two ridges that encircle the crater ejecta--this type of ejecta deposit is sometimes called a double-lobe rampart deposit. The MOC image shows that this particular crater also has 'normal' ejecta that occurs out on the plains, beyond the outermost ridge of the main, fluidized ejecta deposit.

Fluidized or 'rampart' ejecta deposits have long been thought by many Mars scientists to result from an impact into a surface that contains water. The water would have been underground, and could have been frozen or liquid. According to the prevailing model, when the meteor hit, this water was released--along with tons of rock and debris--and the ejecta flowed like mud. Images with resolutions higher than those presently attainable from the 11.6 hr elliptical orbit are needed to see the specific features (such as large boulders 'rafted' by the dense mud) that would confirm or refute this model. Such images may be acquired once MGS is in its mapping orbit.

MOC image 47903 was received and processed by the MOC team at Malin Space Science Systems on Monday afternoon (PDT), August 10, 1998. The image center is located at 27.92oN latitude and 184.66oW longitude, in the northern Tartarus Montes region.

1998-01-01

292

Chemical vapor deposition sciences  

SciTech Connect

Chemical vapor deposition (CVD) is a widely used method for depositing thin films of a variety of materials. Applications of CVD range from the fabrication of microelectronic devices to the deposition of protective coatings. New CVD processes are increasingly complex, with stringent requirements that make it more difficult to commercialize them in a timely fashion. However, a clear understanding of the fundamental science underlying a CVD process, as expressed through computer models, can substantially shorten the time required for reactor and process development. Research scientists at Sandia use a wide range of experimental and theoretical techniques for investigating the science of CVD. Experimental tools include optical probes for gas-phase and surface processes, a range of surface analytic techniques, molecular beam methods for gas/surface kinetics, flow visualization techniques and state-of-the-art crystal growth reactors. The theoretical strategy uses a structured approach to describe the coupled gas-phase and gas-surface chemistry, fluid dynamics, heat and mass transfer of a CVD process. The software used to describe chemical reaction mechanisms is easily adapted to codes that model a variety of reactor geometries. Carefully chosen experiments provide critical information on the chemical species, gas temperatures and flows that are necessary for model development and validation. This brochure provides basic information on Sandia`s capabilities in the physical and chemical sciences of CVD and related materials processing technologies. It contains a brief description of the major scientific and technical capabilities of the CVD staff and facilities, and a brief discussion of the approach that the staff uses to advance the scientific understanding of CVD processes.

NONE

1992-12-31

293

Sediment Transport and Deposition  

NSDL National Science Digital Library

This document provides an overview of the transport and deposition of sediments in an estuarine environment. Since the estuary is the meeting ground of the forces of the river current and the tidal forces of the sea, conditions are always changing and are also affected by the weather and the tides. The discussion includes how rivers with faster currents can transport larger sediment particles, how only increasingly smaller sediment particles can remain suspended in the water as current slows, and how salt water which is encountered as the river meets the sea can cause the tiny silt particles to flocculate and "rain" out of the water.

294

Sediment Transport and Deposition  

NSDL National Science Digital Library

This document provides an overview of the transport and deposition of sediments in an estuarine environment. Since the estuary is the meeting ground of the forces of the river current and the tidal forces of the sea, conditions are always changing and are also affected by the weather and the tides. The discussion includes how rivers with faster currents can transport larger sediment particles, how only increasingly smaller sediment particles can remain suspended in the water as current slows, and how salt water which is encountered as the river meets the sea can cause the tiny silt particles to flocculate and "rain" out of the water.

Oberrecht, Kenn

2007-07-05

295

Acid Deposition Lab  

NSDL National Science Digital Library

In this activity students will design an apparatus and carry out tests of fossil fuels to determine their impact on acid deposition by placing a small amount of a fossil fuel on a cotton puff and burning it to measure if acidic compounds are given off. Students will provide a diagram of their collection device and describe how it should function. Students will then draw a map showing the location of their precipitation collector and develop a graph or chart based on the results they have collected.

296

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

297

Vacuum deposition system  

SciTech Connect

The Physics Section vacuum deposition system is available for several types of thin film techniques. This vacuum evaporation system operates in the high vacuum range. The evaporation source is a resistive heating element, either a boat or a filament design. Coating is then line of sight from the source. Substrates to be coated can have a maximum diameter of 17 inches. At this time the variations in the thickness of the coatings can be controlled, by monitor, to within about 100 angstroms. The system diagrams follow the Operation Procedures and the Sample Coating Procedures provided in this document. 3 figs.

Austin, S.; Bark, D.

1990-05-31

298

Pollutant deposition in mountainous terrain  

SciTech Connect

Theoretical considerations suggest that the high elevation forests in mountainous areas receive substantially more atmospheric deposition than do the forests of the surrounding lowlands. Wet deposition should increase with elevation because of orographic enhancement of precipitation and increased deposition of snow, which may be more polluted than rain. Dry deposition should be greater in high-elevation forests because of greater wind speeds, higher relative humidities, greater surface area of vegetation present during the entire year, and greater filtering efficiency of needles compared to broad leaves. Somewhat lower concentrations of airborne particles and gases at remote high elevation sites may act to diminish the elevational increase of dry deposition to some extent. In addition to increased wet and dry deposition, cloud water deposition is likely to be significant at high elevations because of the frequent presence of wind-driven clouds. At low elevations, clouds and fogs are probably negligible as a deposition vector because they occur less frequently and are usually associated with still air. Experimental verification of these expected trends is not easily found, but studies on cloud water deposition and lead accumulation suggest their accuracy. Additional data on air quality, meteorology, and precipitation chemistry are needed for high elevations before atmospheric deposition of any airborne substance can be determined with certainty. 31 references.

Lovett, G.M.

1983-01-01

299

Upland interfluve (Doab) deposition: Alternative model to muddy overbank deposits  

Microsoft Academic Search

Summary  Major alluvial plains contain large tracts of fine-grained muddy sediments, deposited away from the main river channels, which\\u000a are mostly classed as overbank or floodplain deposits. Systematic study of the Ganga plain shows that such large tracts of\\u000a deposition of muddy sediments are located several metres above the major channels, and are not flooded by overtopping of the\\u000a major river

Indra Bir Singh; Pradeep Srivastava; Shikha Sharma; Maneesh Sharma; Dhruv Sen Singh; Govindaraja Rajagopalan; Urea Kant Shukla

1999-01-01

300

Deposit formation in hydrocarbon fuels  

NASA Technical Reports Server (NTRS)

The hydrocarbon fuels RP-1, commercial-grade propane, JP-7 and chemically pure propane were subjected to tests in a high pressure fuel coking apparatus in order to evaluate their thermal decomposition limits and carbon deposition rates in heated copper tubes. A fuel thermal stability parametric evaluation was conducted at 136-340 atmospheres, bulk fuel velocities of 6-30 m/sec, and tube wall temperatures of 422-811 K, and the effect of inside wall material on deposit formation was evaluated in tests using nickel-plated tubes. Results show RP-1 deposit formation at wall temperatures between 600 and 800 K, with peak deposit formation near 700 K. Substitution of deoxygenated JP-7 for RP-1 showed no improvement, and the carbon deposition rates for propane fuels were found to be higher than those of either of the kerosene fuels. Nickel plating of the tube walls significantly reduced RP-1 carbon deposition rates.

Roback, R.; Szetela, E. J.; Spadaccini, L. J.

1982-01-01

301

Chemical vapor deposition growth  

NASA Technical Reports Server (NTRS)

The chemical vapor deposition (CVD) method for the growth of Si sheet on inexpensive substrate materials is investigated. The objective is to develop CVD techniques for producing large areas of Si sheet on inexpensive substrate materials, with sheet properties suitable for fabricating solar cells meeting the technical goals of the Low Cost Silicon Solar Array Project. Specific areas covered include: (1) modification and test of existing CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using standard and near-standard processing techniques.

Ruth, R. P.; Manasevit, H. M.; Kenty, J. L.; Moudy, L. A.; Simpson, W. I.; Yang, J. J.

1976-01-01

302

Carbonate ramp depositional systems  

NASA Astrophysics Data System (ADS)

The classification, tectonic settings, stratigraphy and early diagenesis of carbonate ramp systems are reviewed. Carbonate ramps are common in all geological periods, but were dominant at times when reef-constructing organisms were absent or inhibited. Ramps can be subdivided into inner-, mid-, and outer-ramp environments. The mid-ramp zone extends from fair-weather wave base to normal storm wave base, although the water depths which these boundaries represent vary. An additional outer-slope environment occurs on distally steepened ramps. As with siliciclastic shelves, a range of wave-, storm-, and tide-dominated ramps can be recognised and this forms the most convenient basis for ramp classification. The carbonate productivity profile of ramps differs from that of rimmed shelves, with the inner ramp showing lower production rates than comparable shallow-water facies on rimmed shelves. The zone of greatest organic carbonate sediment production appears to have shifted from the mid-ramp to the inner ramp since the Late Jurassic. Carbonate ramps occur in most types of sedimentary basin but are best developed where subsidence is flexural and gradients are slight over large areas, as in foreland and cratonic-interior basins and along passive margins. The featureless depositional profiles of many ramps means that sequence geometries are best observed on regional seismic lines. Some show low-angle sigmoidal or shingled clinoforms, suggesting that ramps may seldom be "homoclinal", but possess subtle slope geometries which reflect depositional environments. Because of their low-angle slopes, ramps respond differently to rimmed shelves during relative sea-level changes although results seem to be strongly dependent on the rate of relative sea-level change. During a minor fall, shallow-ramp facies belts will simply shift basinwards in a "forced regression". In contrast, the whole surface of a steep-sloped, flat-topped rimmed shelf may be exposed so that sediment production ceases or is drastically reduced. During a major fall, shallow ramp-bounded basins may empty completely. Conversely, ramps also flood gradually, whereas rimmed shelves do so more rapidly. Homoclinal ramps develop no resedimented lowstand deposits; rimmed shelves and distally steepened ramps, in contrast, may develop lowstand talus or turbiditic wedges. Distally steepened ramps may behave more like homoclinal ramps during minor base-level falls and like rimmed shelves during major base-level falls. Many ramps consist of layered successions of several ramp sequences stacked one upon the other. Ramp "stacks" of this sort may show gross vertical accretion, but individual ramp sequences seldom appear to develop in a "keep-up" style, apart from minor organic buildups, as with many rimmed shelves. Steepening of the outer-ramp margin due to tectonism, slope inheritance, or differential sedimentation may promote the development of a distally steepened ramp or rimmed shelf. A wide variety of organisms have constructed buildups in mid- and outer-ramp environments. Isolated buildups may seed early in ramp development, accrete to wave base or sea level, and continue growth by stacking through successive ramp sequences so that depositional and diagenetic features within them are in concert with those of the shallow ramp. The location of isolated buildups on ramps is governed by tectonism, halokinesis, antecedent topography, or by the subtle slope geometry of the previous ramp sequence. Diagenesis on ramps shows some major variations compared with diagenesis on steep-sloped, flat-topped carbonate platforms. Ramp-bounded basins may form prolific petroleum sourcing and reservoiring systems and offer a range of subtle stratigraphic play types and lateral facies variations which determine reservoir quality and distribution. Isolated buildups in the mid- and outer-ramp environments represent one of the commonest petroleum reservoirs in ramp systems and tend to have their foundations in transgressive systems tracts. Grainstone and packstone res

Burchette, T. P.; Wright, V. P.

1992-08-01

303

The deposit size frequency method for estimating undiscovered uranium deposits  

USGS Publications Warehouse

The deposit size frequency (DSF) method has been developed as a generalization of the method that was used in the National Uranium Resource Evaluation (NURE) program to estimate the uranium endowment of the United States. The DSF method overcomes difficulties encountered during the NURE program when geologists were asked to provide subjective estimates of (1) the endowed fraction of an area judged favorable (factor F) for the occurrence of undiscovered uranium deposits and (2) the tons of endowed rock per unit area (factor T) within the endowed fraction of the favorable area. Because the magnitudes of factors F and T were unfamiliar to nearly all of the geologists, most geologists responded by estimating the number of undiscovered deposits likely to occur within the favorable area and the average size of these deposits. The DSF method combines factors F and T into a single factor (F??T) that represents the tons of endowed rock per unit area of the undiscovered deposits within the favorable area. Factor F??T, provided by the geologist, is the estimated number of undiscovered deposits per unit area in each of a number of specified deposit-size classes. The number of deposit-size classes and the size interval of each class are based on the data collected from the deposits in known (control) areas. The DSF method affords greater latitude in making subjective estimates than the NURE method and emphasizes more of the everyday experience of exploration geologists. Using the DSF method, new assessments have been made for the "young, organic-rich" surficial uranium deposits in Washington and idaho and for the solution-collapse breccia pipe uranium deposits in the Grand Canyon region in Arizona and adjacent Utah. ?? 1993 Oxford University Press.

McCammon, R. B.; Finch, W. I.

1993-01-01

304

Top-Down Nanomanufacturing: Deposition  

NSDL National Science Digital Library

This overview of nanotechnology is presented by the NaMCATE project. According to the introductory page, "in related silicon processes for fabrication of MEMS (microelectromechanical devices), deposition of so-called sacrificial layers of oxides or other material are made, and then these layers are removed to free the moving mechanical components from being bonded to the surface." In this module, the various deposition processes are described. Additionally, the module provides three learning activities titled Sputtering Copper, Evaporative Deposition, and Electrochemical Deposition and Chemical Etching. Lastly, a performance assessment and powerpoint presentation are included.Users must create a free login in order to access materials.

2011-09-22

305

(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

306

Sediment and Depositional Environments lab  

NSDL National Science Digital Library

Students will investigate sediment and depositional environments utilizing several different research tools. They will utilize a "Sedimentator" settling tube to investigate energy influences in a depositional environment. Students will investigate hand samples of a coal suite to connect their observations to an understanding of its depositional environment. They will utilize the a USGS web site to make observations concerning Hurricane Katrina sediment transport and deposition. Students will utilize microscopes to make comparisons of different kinds of beach sand, their sources and ultimately the resultant rock types.

Hadley, Ann

307

The short-term effects of ecological restoration on carbon dioxide fluxes from a Molinia caerulea dominated marginal upland blanket bog.  

NASA Astrophysics Data System (ADS)

Peat soils in the UK represent a significant long-term carbon store. Despite this the annual imbalance between uptake and release is small and susceptible to change in response to land management, atmospheric deposition and climate change. The shallow marginal peatlands of Exmoor, southwest England, have historically been subject to extensive drainage and are known to be vulnerable to future changes in climate as they lie at the southern edge of the ombrotrophic peatland climatic envelope. However little is known about the processes that drive CO2 fluxes from degraded Molinia caerulea dominated upland mires or the potential effect that restoration through drainage blocking will have. The Mires-on-the-Moors project (www.upstreamthinking.org), funded by South West Water aims to restore the eco-hydrological functionality to over 2000 hectares of drained mire by April 2015. We hypothesised that such mire restoration will return these upland mires to peat forming/carbon sequestering systems. Partitioned below-ground respiration fluxes as well as biotic and abiotic variables, were collected on various dates in 2012 and 2013 along six transects adjacent to three pairs of drainage ditches. One of each pair was restored by blocking with peat dams in spring 2013 whilst the other remained unrestored to act as a control. Monitoring locations were arranged along transects to investigate the spatial variation in gas fluxes with respect to the drainage ditches. By partitioning below-ground fluxes it was possible to monitor root-derived (autotrophic) and more importantly soil-derived (heterotrophic) respiration providing an insight to the effects of ditch blocking on the long term carbon store. Here we present CO2 fluxes for the growing seasons at two critical stages in the restoration process: (a) immediately pre-restoration and (b) immediately post- restoration, and discuss the temporally and spatially variable processes driving below-ground CO2 fluxes. Respiration rates were comparatively low in these shallow humified peats, with daily mean total, heterotrophic and autotrophic respiration reached 1.34, 0.60 and 0.23 ?molCm-2s-1 respectively. As expected soil temperature had a significant control on respiration rates, once this was accounted for water level showed a weak effect on total and heterotrophic respiration. Distinguishing the effects of ecological restoration between a wetter baseline period and a drier post-restoration period had its challenges. However, by expressing the respiration rates in the restored sites as a proportion of that observed in the control sites, the confounding effect of climate variability could be accounted for. This allowed us to determine that heterotrophic respiration decreased at the restored sites comparative to the control sites following restoration, indicating the immediate effect of restoration was to reduce decomposition of the peat store, with implications for carbon sequestration rates.

Gatis, Naomi; Luscombe, David; Grand-Clement, Emilie; Hartley, Iain; Anderson, Karen; Brazier, Richard E.

2014-05-01

308

Semiconductor and ceramic nanoparticle films deposited by chemical bath deposition  

Microsoft Academic Search

Chemical bath deposition (CBD) has been used to deposit films of metal sulfides, selenides and oxides, together with some miscellaneous compounds, beginning nearly 140 years ago. While it is a well-known technique in a few specific areas (notably photoconductive lead salt detectors, photoelectrodes and more recently, thin film solar cells), it is by and large an under-appreciated technique. The more

Gary Hodes

2007-01-01

309

Hydrothermal alteration of organic matter in uranium ores, Elliot Lake, Canada: Implications for selected organic-rich deposits  

SciTech Connect

Organic matter in the uraniferous Matinenda Formation, Elliot Lake, is preserved in the forms of syngenetic kerogen and solid bitumen as it is in many of the Oklo uranium deposits and in the Witwatersrand gold-uranium ores. The Elliot Lake kerogen is a vitrinite-like material considered to be remnants of the Precambrian cyanobacterial mats. The kerogen at Elliot Lake has reflectances (in oil) ranging from 2.63-7.31% RO{sub max}, high aromaticity, relatively low (0.41-0.60) atomic H/C ratios, and it contains cryptocrystalline graphite. Bitumen, present primarily as dispersed globules (up to 0.5 mm dia.), has reflectances from 0.72-1.32% RO{sub max}, atomic H/C ratios of 0.71-0.81, and is somewhat less aromatic than the kerogen. Overall similarity in molecular compositions indicates that liquid bitumen was derived from kerogen by processes similar to hydrous pyrolysis. The carbon isotopic composition of kerogen ({minus}15.62 to {minus}24.72%), and the now solid bitumen ({minus}25.91 to {minus}33.00%) are compatible with these processes. Despite having been subjected to several thermal episodes, ca. 2.45 Ga old kerogen of microbiological origin here survived as testimony of the antiquity of life on Earth. U-Pb isotopic data from discrete kerogen grains at Elliot Lake form a scattered array intersecting concordia at 2130 {+-} 100 Ma, correspond to the Nipissing event. U-Pb systems were totally reset by this event. Uranium and lead show subsequently partial mobility, the average of which is indicated by the lower concordia intersect of 550 {+-} 260 Ma. The migrated bitumen contains virtually no uranium and thorium but has a large excess of {sup 206}Pb, which indicates that the once liquid bitumen must have acted as a sink for mobile intermediate decay products of {sup 238}U. Emplacement of the Nipissing diabase may have been responsible for producing the bitumen and, indirectly, for its enrichment in {sup 206}Pb as a result of outgassing of {sup 222}Rn.

Mossman, D.J. [Mount Allison Univ., Sackville (Canada)] [Mount Allison Univ., Sackville (Canada); Nagy, B. [Univ. of Arizona, Tucson (United States)] [Univ. of Arizona, Tucson (United States); Davis, D.W. [Royal Ontario Museum, Toronto, Ontario (Canada)] [Royal Ontario Museum, Toronto, Ontario (Canada)

1993-07-01

310

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...

311

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

312

Chemical vapour deposition of coatings  

Microsoft Academic Search

Chemical Vapour Deposition (CVD) of films and coatings involve the chemical reactions of gaseous reactants on or near the vicinity of a heated substrate surface. This atomistic deposition method can provide highly pure materials with structural control at atomic or nanometer scale level. Moreover, it can produce single layer, multilayer, composite, nanostructured, and functionally graded coating materials with well controlled

K. L. Choy

2003-01-01

313

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

314

Io - A surface evaporite deposit  

Microsoft Academic Search

A model is suggested for Io's surface composition involving evaporite salt deposits, rich in sodium and sulfur. According to this model, these deposits were produced as a result of the migration of salt-saturated aqueous solutions to Io's surface from a warm or hot interior followed by loss of the water to space. This model satisfies cosmochemical constraints based on Io's

F. P. Fanale; T. V. Johnson; D. L. Matson

1974-01-01

315

Economic considerations of atmospheric deposition  

Microsoft Academic Search

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

Shriner

1987-01-01

316

Physical vapor deposition tool coatings  

Microsoft Academic Search

Physical vapor deposition (PVD) of hard coatings such as titanium nitride have been an industrial reality since the beginning of the 1980s. Two PVD processes, low voltage electron beam and cathodic arc deposition, were responsible for the early commercial success of hard coatings on high speed steel tooling. Since that time, two other PVD processes have also been prosperous in

William D. Sproul

1996-01-01

317

Thermal Plasma Chemical Vapor Deposition  

Microsoft Academic Search

Diamond has many unrivaled properties and has great application potentials in modern industry. Among various metastable chemical vapor deposition methods for producing diamond, thermal plasma chemical vapor deposition has shown advantages of offering high growth rates and high quality. However, systematic parametric studies are needed for optimization of the process. This study investigates the effects of substrate materials, substrate temperatures,

Zhipeng Lu

1991-01-01

318

Geochemistry and mineralogy of a uraniferous subbituminous coal  

Microsoft Academic Search

Analytical studies of partially weathered Red Desert subbituminous coal from Wyoming were made to determine the mineralogical composition and geochemical characteristics of the sample in relation to the presence of U in the coal. The coal, obtained from the Luman No. 1 bed, was subjected to semiquantitative spectrographic analysis (28 elements) and x-ray diffraction. Spectrographic analysis was reported on 3

I. A. Breger; M. Deul; R. Meyrowitz

1955-01-01

319

Ni-Co laterite deposits  

USGS Publications Warehouse

Nickel-cobalt (Ni-Co) laterite deposits are an important source of nickel (Ni). Currently, there is a decline in magmatic Ni-bearing sulfide lode deposit resources. New efforts to develop an alternative source of Ni, particularly with improved metallurgy processes, make the Ni-Co laterites an important exploration target in anticipation of the future demand for Ni. This deposit model provides a general description of the geology and mineralogy of Ni-Co laterite deposits, and contains discussion of the influences of climate, geomorphology (relief), drainage, tectonism, structure, and protolith on the development of favorable weathering profiles. This model of Ni-Co laterite deposits represents part of the U.S. Geological Survey Mineral Resources Program's effort to update the existing models to be used for an upcoming national mineral resource assessment.

Marsh, Erin E.; Anderson, Eric D.

2011-01-01

320

Dense Deposit Disease  

PubMed Central

Dense deposit disease (DDD) is an orphan disease that primarily affects children and young adults without sexual predilection. Studies of its pathophysiology have shown conclusively that it is caused by fluid-phase dysregulation of the alternative pathway of complement, however the role played by genetics and autoantibodies like C3 nephritic factors must be more thoroughly defined if we are to make an impact in the clinical management of this disease. There are currently no mechanism-directed therapies to offer affected patients, half of whom progress to end stage renal failure disease within 10 years of diagnosis. Transplant recipients face the dim prospect of disease recurrence in their allografts, half of which ultimately fail. More detailed genetic and complement studies of DDD patients may make it possible to identify protective factors prognostic for naïve kidney and transplant survival, or conversely risk factors associated with progression to renal failure and allograft loss. The pathophysiology of DDD suggests that a number of different treatments warrant consideration. As advances are made in these areas, there will be a need to increase healthcare provider awareness of DDD by making resources available to clinicians to optimize care for DDD patients.

Smith, Richard J.H; Harris, Claire L.; Pickering, Matthew C.

2011-01-01

321

Chemical vapor deposition growth  

NASA Technical Reports Server (NTRS)

A laboratory type CVD reactor system with a vertical deposition chamber and sample pedestal heated by an external RF coil has been extensively modified by installation of mass flow controllers, automatic process sequence timers, and special bellows-sealed air-operated valves for overall improved performance. Various film characterization procedures, including classical metallography, SEM analyses, X ray diffraction analyses, surface profilometry, and electrical measurements (resistivity, carrier concentration, mobility, spreading resistance profiles, and minority-carrier lifetime by the C-V-t method) area used to correlate Si sheet properties with CVD parameters and substrate properties. Evaluation procedures and measurements are given. Experimental solar cell structures were made both in epitaxial Si sheet (on sapphire substrates) and in polycrystalline material on alumina substrates, the former to provide an indication of what might be an upper limit on performance of the latter. Preliminary results are given, as obtained in cell structures not specially designed to allow for the unique properties of the sheet material, and fabricated in material known to be far from optimum for photovoltaic performance. Low power conversion efficiencies have been obtained in the epitaxial as well as the polycrystalline Si sheet.

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

1976-01-01

322

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

323

Melas Chasma Deposits  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Erosion of the interior layered deposits of Melas Chasma, part of the huge Valles Marineris canyon system, has produced cliffs with dramatic examples of spur and gulley morphology and beautiful exposures of finely layered sediments.

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.

Image information: VIS instrument. Latitude -10.4, Longitude 284.9 East (75.1 West). 19 meter/pixel resolution.

2003-01-01

324

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 ...

325

Deposition properties of selective tungsten chemical vapor deposition  

Microsoft Academic Search

This work investigates the basic deposition properties of selective tungsten chemical vapor deposition (W-CVD) using the process of silane reduction of WF6 with the SiH4\\/WF6 flow rate ratio less than 0.6 over the temperature range 280–350 °C. Selective W-CVD was performed on a contact hole patterned silicon substrate with in situ NF3 plasma etching of the silicon substrate prior to

Wen-Kuan Yeh; Mao-Chieh Chen; Pei-Jan Wang; Lu-Min Liu; Mou-Shiung Lin

1996-01-01

326

Particle deposition in ventilation ducts  

SciTech Connect

Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 {micro}m were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on the experimental measurements was applied to evaluate particle losses in supply and return duct runs. Model results suggest that duct losses are negligible for particle sizes less than 1 {micro}m and complete for particle sizes greater than 50 {micro}m. Deposition to insulated ducts, horizontal duct floors and bends are predicted to control losses in duct systems. When combined with models for HVAC filtration and deposition to indoor surfaces to predict the ultimate fates of particles within buildings, these results suggest that ventilation ducts play only a small role in determining indoor particle concentrations, especially when HVAC filtration is present. However, the measured and modeled particle deposition rates are expected to be important for ventilation system contamination.

Sippola, Mark R.

2002-09-01

327

Particle deposition in granular media  

NASA Astrophysics Data System (ADS)

The purpose of the studies is aimed at obtaining a quantitative understanding of the process of deposition of aerosol particles from gas streams flowing through granular media and the formulation of a basic framework for describing the process. During the period June 1, 1988 to date, a number of investigations have been carried out including: transient behavior of granular filtration, modification of porous media model for aerosol deposition studies, stochastic simulation of particle deposition, and analysis of filter candle performance. Results of the studies are discussed separately.

Chi, Tien

328

Deposition Surface Properties and the Spectra of Deposited Ices  

NASA Astrophysics Data System (ADS)

The spectra of adsorbed species, especially thin films, are known to show effects related to the nature of the deposition surface. Subtle effects, such as shifts in line positions, are common, and must be recognized to ensure proper spectral assignments of the deposited material. We have also observed more dramatic effects, including low temperature crystallization (LTC), which appears to be surface-dependent as well. Here, the ice film forms in the crystalline phase at deposition temperatures well below the amorphous-to-crystalline transition point. Since astronomers often use the phase of the deposited ice to give important clues about the thermal- and radiation-history of the object, a better understanding of the effect of the surface on the spectrum of the deposited ice is required. To that end, we have measured a number of surface properties (surface area, pore volumes, and pore size distributions) for a variety of amorphous silicate interstellar grain analogs, and have studied the IR spectra of methanol (and other ices) deposited on these materials. Thermally induced modifications to some of these surfaces have also been examined. Results and correlations among the data will be presented.

Ferrante, R. F.; Moore, M. H.; Nuth, J. A.

1998-09-01

329

Nano-Modulated Ceramic Coating Deposition System.  

National Technical Information Service (NTIS)

This report outlines the design, construction, and implementation of a Nano-modulated ceramic coating deposition system. The deposition system was designed to deposit multilayer (superlattice) coatings of two or more oxide or other non-conducting material...

W. D. Sproul A. R. Lefkow

1996-01-01

330

The zeolite deposits of Greece  

USGS Publications Warehouse

Zeolites are present in altered pyroclastic rocks at many localities in Greece, and large deposits of potential economic interest are present in three areas: (1) the Evros region of the province of Thrace in the north-eastern part of the Greek mainland; (2) the islands of Kimolos and Poliegos in the western Aegean; and (3) the island of Samos in the eastern Aegean Sea. The deposits in Thrace are of Eocene-Oligocene age and are rich in heulandite and/or clinoptilolite. Those of Kimolos and Poliegos are mainly Quaternary and are rich in mordenite. Those of Samos are Miocene, and are rich in clinoptilolite and/or analcime. The deposits in Thrace are believed to have formed in an open hydrological system by the action of meteoric water, and those of the western Aegean islands in a similar way but under conditions of high heat flow, whereas the deposits in Samos were formed in a saline-alkaline lake.

Stamatakis, M. G.; Hall, A.; Hein, J. R.

1996-01-01

331

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...

332

Acoustic Wave Electroless Deposition Monitor.  

National Technical Information Service (NTIS)

A new type of electroless deposition monitor has been constructed from a monolithic acoustic wave device utilizing plate modes with shear displacement components. This device, which operates at 158 MHz, provides a highly accurate means of measuring mass c...

A. J. Ricco S. J. Martin

1987-01-01

333

Chemical vapour deposition of superconductors  

Microsoft Academic Search

Chemical vapour deposition processes (CVD) can produce metastable fine-grained materials as well as epitaxial coatings and can have a very large throwing power depending on the process parameters. Therefore, CVD is an prospective method to deposit high-temperature superconducting materials withTc?10 K. One of the first superconductors which were produced was Nb3Sn on tapes and single wires. This superconducting material is,

G. Wahl; F. Schmaderer

1989-01-01

334

Chemical vapour deposition of superconductors  

Microsoft Academic Search

Chemical vapour deposition processes (CVD) can produce metastable fine-grained materials as well as epitaxial coatings and\\u000a can have a very large throwing power depending on the process parameters. Therefore, CVD is an prospective method to deposit\\u000a high-temperature superconducting materials withT\\u000a c?10 K. One of the first superconductors which were produced was Nb3Sn on tapes and single wires. This superconducting material

G. Wahl; F. Schmaderer

1989-01-01

335

Acid rain and dry deposition  

SciTech Connect

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 precipitation metals and organics.

Canter, L.W.

1985-01-01

336

Vapor deposition of hardened niobium  

DOEpatents

A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

Blocher, Jr., John M. (Columbus, OH); Veigel, Neil D. (Columbus, OH); Landrigan, Richard B. (Columbus, OH)

1983-04-19

337

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

338

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

339

A radon progeny deposition model  

SciTech Connect

The next generation low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly {sup 222}Rn) and its subsequent progeny present in an experiment are potential backgrounds, also problematic is the deposition of radon progeny on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by progeny supported by the long half life (22 y) of {sup 210}Pb on sensitive locations of a detector. An understanding of the potential surface contamination from deposition will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of progeny onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to deposit radon progeny on various surfaces under a controlled environment in order to develop a deposition model. Results from this test stand and the resulting deposition model are presented.

Rielage, Keith [Los Alamos National Laboratory; Elliott, Steven R [Los Alamos National Laboratory; Hime, Andrew [Los Alamos National Laboratory; Guiseppe, Vincent E [Los Alamos National Laboratory; Westerdale, S. [MIT

2010-12-01

340

A Radon Progeny Deposition Model  

SciTech Connect

The next generation low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly {sup 222}Rn) and its subsequent progeny present in an experiment are potential backgrounds, also problematic is the deposition of radon progeny on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by progeny supported by the long half life (22 y) of {sup 210}Pb on sensitive locations of a detector. An understanding of the potential surface contamination from deposition will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of progeny onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to deposit radon progeny on various surfaces under a controlled environment in order to develop a deposition model. Results from this test stand and the resulting deposition model are presented.

Guiseppe, V. E. [University of South Dakota, Vermillion, South Dakota 57069 (United States); Elliott, S. R.; Hime, A.; Rielage, K. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Westerdale, S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2011-04-27

341

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

342

The Limits to Peat Bog Growth  

Microsoft Academic Search

Not less than 2% of the Earth's land surface is peat-covered, so it is important to try to understand the dynamics of peat accumulation. Peat-forming systems (mires) accumulate peat because conditions within them impede the decay of the plant material produced by their surface vegetation. This paper concerns the rate of peat production and some unexpected consequences of the processes

R. S. Clymo

1984-01-01

343

BOG miniseminar: Otolaryngology managed care symposium  

Microsoft Academic Search

This miniseminar will present all sides of the issues with the proposed panel being comprised of both leading physicians and managed care executives. The audience will participate with interactive responses and active discussions from the floor. The panelist will review (1) the historical background of the health care industry; (2) a market analysis of the current state of managed care;

J. Pablo Stolovitzky; Michael D. Maves; Charles F. Koopmann; John Watts

2004-01-01

344

Metal film deposition by laser breakdown chemical vapor deposition  

SciTech Connect

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 CO/sub 2/ 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

345

Development features of a supergene zone on a uranium-phosphorus deposit  

SciTech Connect

It has been established that an old linear weathering crust developed on a layer-like, steeply dipping body of uraniferous phosphorites. In the upper part it consists of a karst cavity, and deeper down, an unusual deep-seated zone of layered oxidation immediately below which there is an enrichment zone of the phosphorites in a visible pitchblende mineralization. The latter is characterized by a series of specific features, spatially and genetically clearly associated with distinct supergene processes of hydrohematitization and hydrogeothitization, and is supergene in origin.

Glagolev, N.A.

1980-09-01

346

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

347

Sequential deposition etch techniques for the selective deposition of tungsten  

SciTech Connect

We report on the use of a deposition/etch approach to the loss of selectivity problem, using high activity fluorine chemistries in the etch step. Proof-of-concept experiments were initially performed in a hot wall system, the excellent results obtained lead us to prove out the concept in a commercially available cold wall Genus reactor. We observed that WF{sub 6} is ineffective as an etchant of W. The technique has been able to produce perfectly selective depositions 1 micron thick in both hot wall, and cold wall, systems. Sheet resistivity values and film morphology are good. 9 refs., 4 figs., 1 tab.

Fleming, J.G.; Omstead, T.R.; Dominguez, F.

1991-01-01

348

Particle Deposition During Airway Closure  

NASA Astrophysics Data System (ADS)

Inhaled aerosol particles deposit in the lung and may be from environmental, toxic, or medical therapy sources. While much research focuses on inspiratory deposition, primarily at airway bifurcations due to inertial impaction, there are other mechanisms that allow the particles to reach the airway surface, such as gravitational settling and diffusion depending on particle size. We introduce a new mechanism not previously studied, i.e. aerosol deposition from airway closure. The airways are lined with a liquid layer. Due to the surface tension driven instability, a liquid plug can form from this layer which blocks the airway. This process of airway closure tends to occur toward the end of expiration. In this study, the efficiency of the impaction of the particles during airway closure will be investigated. The particles will be released from the upstream of the airway and convected by the air flow and deposited onto the closing liquid layer. We solve the governing equations using a finite volume approach in conjunction with a sharp interface method for the interfaces. Once the velocity field of the gas flow is obtained, the path of the particles will be calculated and the efficiency of the deposition can be estimated.

Tai, Cheng-Feng; Halpern, David; Grotberg, James

2010-11-01

349

Particle Deposition During Airway Closure  

NASA Astrophysics Data System (ADS)

Inhaled aerosol particles deposit in the lung and may be from environmental, toxic, or medical therapy sources. While much research focuses on inspiratory deposition, primarily at airway bifurcations due to inertial impaction, there are other mechanisms that allow the particles to reach the airway surface, such as gravitational settling and diffusion depending on particle size. We introduce a new mechanism not previously studied, i.e. aerosol deposition from airway closure. The airways are lined with a liquid layer. Due to the surface tension driven instability, a liquid plug can form from this layer which blocks the airway. This process of airway closure tends to occur toward the end of expiration. In this study, the efficiency of the impaction of the particles during airway closure will be investigated. The particles will be released from the upstream of the airway and convected by the air flow and deposited onto the closing liquid layer. We solve the governing equations using a finite volume approach in conjunction with a sharp interface method for the interfaces. Once the velocity field of the gas flow is obtained, the path of the particles will be calculated and the efficiency of the deposition can be estimated.

Tai, Cheng-Feng; Halpern, David; Grotberg, James B.

2011-11-01

350

Acidification, nitrogen deposition and rapid vegetational change in a small valley mire in Yorkshire  

Microsoft Academic Search

Changes in vegetation and environment at Askham Bog, a small valley mire near York, UK, have been followed over a period of 13 years by resurveying sites recorded in 1978 and by studying permanent quadrats. The site has a concentrically zoned series of vegetation types, with base-rich fen vegetation around the margins and acidophilous, species-poor vegetation on acid peat in

P. Hogg; P. Squires; A. H. Fitter

1995-01-01

351

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.

352

Atmospheric deposition to high-elevation forests  

SciTech Connect

Three important phenomena characterize atmospheric deposition to high-elevation forests: (1) multiple deposition mechanisms (wet, dry, and cloud deposition), (2) high rates of deposition, and (3) high spatial variability. The high rates of deposition are caused by changes in meteorological conditions with elevation, especially increasing wind speed and cloud immersion frequency. The high spatial variability of deposition is a result of the regulation of cloud and dry deposition rates by microclimatic and canopy structure conditions, which can be extremely heterogeneous in mountain landscapes. Spruce-fir forests are often [open quotes]hot spots[close quotes] of deposition when viewed in a landscape or regional context because of their elevation, exposure, and evergreen canopy. In this talk we will consider atmospheric depositions to high-elevation forests in both the northeastern and southeastern U.S., using field data and geographic information systems to illustrate deposition patterns.

Lovett, G.M.; Weathers, K.C.; Lindberg, S.E. (Institute of Ecosystem Studies, Millbrook, NY (United States) Oak Ridge National Lab., TN (United States))

1994-06-01

353

Combustion Iron Distribution and Deposition  

NASA Astrophysics Data System (ADS)

Iron is hypothesized to be an important micronutrient for ocean biota, thus modulating carbon dioxide uptake by the ocean biological pump. Studies have assumed that atmospheric deposition of iron to the open ocean is predominantly from mineral aerosols. For the first time, we model the source, transport and deposition of iron from combustion sources. Iron is produced in small quantities during fossil fuel burning, incinerator use, and biomass burning. The sources of combustion iron are concentrated in the industrialized regions and biomass burning regions, largely in the tropics. Model results suggest that combustion iron can represent up to 50 percent of the total iron deposited, but over open ocean regions is usually less than 5 percent of the total iron, with the highest values (less than 30 percent) close to the East Asian continent in the North Pacific. For ocean biogeochemistry the bioavailability of the iron is important, and this is often estimated by the fraction which is soluble (Fe(II)). Previous studies have argued that atmospheric processing of the relatively insoluble Fe(III) occurs to make it more soluble (Fe(II)). Modeled estimates of soluble iron amounts based solely on atmospheric processing as simulated here cannot match the variability in daily averaged in situ concentration measurements in Korea, which is located close to both combustion and dust sources. The best match to the observations is that there is substantial direct emissions of soluble iron from combustion processes. If we assume observed soluble Fe/black carbon (BC) ratios in Korea are representative of the whole globe, we obtain the result that deposition of soluble iron from combustion contribute 20-100 percent of the soluble iron deposition over many ocean regions. This implies that more work should be done refining the emissions and deposition of combustion sources of soluble iron globally.

Luo, C.; Mahowald, N.; Bond, T.; Chuang, P.; Artaxo, P.; Siefert, R.; Chen, Y.; Schauer, J.

2007-05-01

354

Pituicytoma with gelsolin amyloid deposition.  

PubMed

Pituicytoma is a rare low-grade (WHO grade I) sellar region glioma. Among sellar tumors, pituitary adenomas, mainly prolactinomas, may show amyloid deposits. Gelsolin is a ubiquitous calcium-dependent protein that regulates actin filament dynamics. Two known gene point mutations result in gelsolin amyloid deposition, a characteristic feature of a rare type of familial amyloid polyneuropathy (FAP), the Finnish-type FAP, or hereditary gelsolin amyloidosis (HGA). HGA is an autosomal-dominant systemic amyloidosis, characterized by slowly progressive neurological deterioration with corneal lattice dystrophy, cranial neuropathy, and cutis laxa. A unique case of pituicytoma with marked gelsolin amyloid deposition in a 67-year-old Chinese woman is described. MRI revealed a 2.6-cm well-circumscribed, uniformly contrast-enhancing solid sellar mass with suprasellar extension. Histologically, the lesion was characterized by solid sheets and fascicles of spindle cells with slightly fibrillary cytoplasm and oval nuclei with pinpoint nucleoli. Surrounding brain parenchyma showed marked reactive piloid gliosis. Remarkably, conspicuous amyloid deposits were identified as pink homogeneous spherules on light microscopy that showed apple-green birefringence on Congo red with polarization. Mass spectrometric-based proteomic analysis identified the amyloid as gelsolin type. Immunohistochemically, diffuse reactivity to S100 protein and TTF1, focal reactivity for GFAP, and no reactivity to EMA, synaptophysin, and chromogranin were observed. HGA-related mutations were not identified in the tumor. No recurrence was noted 14 months after surgery. To the knowledge of the authors, amyloid deposition in pituicytoma or tumor-associated gelsolin amyloidosis has not been previously described. This novel finding expands the spectrum of sellar tumors that may be associated with amyloid deposition. PMID:23817895

Ida, Cristiane M; Yan, Xiaoling; Jentoft, Mark E; Kip, N Sertac; Scheithauer, Bernd W; Morris, Jonathan M; Dogan, Ahmet; Parisi, Joseph E; Kovacs, Kalman

2013-09-01

355

TULSA UNIVERSITY PARAFFIN DEPOSITION PROJECTS  

SciTech Connect

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 single-phase oil flow, these predictive capabilities are not suitable for the multiphase flow conditions encountered in most flowlines and wellbores. For deepwater applications in the Gulf of Mexico, it is likely that multiphase production streams consisting of crude oil, produced water and gas will be transported in a single multiphase pipeline to minimize capital cost and complexity at the mudline. Existing single-phase (crude oil) paraffin deposition predictive tools are clearly inadequate to accurately design these pipelines, because they do not account for the second and third phases, namely, produced water and gas. The objective of this program is to utilize the current test facilities at The University of Tulsa, as well as member company expertise, to accomplish the following: enhance our understanding of paraffin deposition in single and two-phase (gas-oil) flows; conduct focused experiments to better understand various aspects of deposition physics; and, utilize knowledge gained from experimental modeling studies to enhance the computer programs developed in the previous JIP for predicting paraffin deposition in single and two-phase flow environments. These refined computer models will then be tested against field data from member company pipelines.

Cem Sarica; Michael Volk

2004-06-01

356

The deposit size frequency method for estimating undiscovered uranium deposits  

Microsoft Academic Search

The deposit size frequency (DSF) method has been developed as a generalization of the method that was used in the National Uranium Resource Evaluation (NURE) program to estimate the uranium endowment of the United States. The DSF method overcomes difficulties encountered during the NURE program when geologists were asked to provide subjective estimates of (1) the endowed fraction of an

Richard B. McCammon; Warren I. Finch

1993-01-01

357

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

Federal Register 2010, 2011, 2012, 2013

...United States customers. These customers include active duty and reserve...business model, operations and customers, including: a. The number...deposits are insured. B. Customers 1. Please describe the impact...submitted to the Office of Management and Budget for review....

2013-02-19

358

Fluidized bed deposition of diamond  

DOEpatents

A process for coating a substrate with diamond or diamond-like material including maintaining a substrate within a bed of particles capable of being fluidized, the particles having substantially uniform dimensions and the substrate characterized as having different dimensions than the bed particles, fluidizing the bed of particles, and depositing a coating of diamond or diamond-like material upon the substrate by chemical vapor deposition of a carbon-containing precursor gas mixture, the precursor gas mixture introduced into the fluidized bed under conditions resulting in excitation mechanisms sufficient to form the diamond coating.

Laia, Jr., Joseph R. (Los Alamos, NM); Carroll, David W. (Los Alamos, NM); Trkula, Mitchell (Los Alamos, NM); Anderson, Wallace E. (Los Alamos, NM); Valone, Steven M. (Santa Fe, NM)

1998-01-01

359

Vapor deposition of thin films  

DOEpatents

A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

1992-01-01

360

Deposition of diamondlike carbon films  

NASA Technical Reports Server (NTRS)

A diamondlike carbon film is deposited in the surface of a substrate by exposing the surface to an argon ion beam containing a hydrocarbon. The current density in the ion beam is low during initial deposition of the film. Subsequent to this initial low current condition, the ion beam is increased to full power. At the same time, a second argon ion beam is directed toward the surface of the substrate. The second ion beam has an energy level much greater than that of the ion beam containing the hydrocarbon. This addition of energy to the system increases mobility of the condensing atoms and serves to remove lesser bound atoms.

Mirtich, M. J.; Sovey, J. S.; Banks, B. A. (inventors)

1984-01-01

361

Soot Deposit Properties in Practical Flames  

SciTech Connect

Soot deposition from hydrocarbon flames was investigated in order to evaluate the evolution of the deposits during the transient process of heating an object that starts with a cold metal surface that is exposed to a flame. The study focused on the fire/metal surface interface and the critical issues associated with the specification of the thermal boundaries at this interface, which include the deposition of soot on the metal surface, the chemical and physical properties of the soot deposits and their subsequent effect on heat transfer to the metal surface. A laboratory-scale device (metallic plates attached to a water-cooled sampling probe) was designed for studying soot deposition in a laminar ethylene-air premixed flame. The metallic plates facilitate the evaluation of the deposition rates and deposit characteristics such as deposit thickness, bulk density, PAH content, deposit morphology, and thermal properties, under both water-cooled and uncooled conditions. Additionally, a non-intrusive Laser Flash Technique (in which the morphology of the deposit is not modified) was used to estimate experimental thermal conductivity values for soot deposits as a function of deposition temperature (water-cooled and uncooled experiments), location within the flame and chemical characteristics of the deposits. Important differences between water-cooled and uncooled surfaces were observed. Thermophoresis dominated the soot deposition process and enhanced higher deposition rates for the water-cooled experiments. Cooler surface temperatures resulted in the inclusion of increased amounts of condensable hydrocarbons in the soot deposit. The greater presence of condensable material promoted decreased deposit thicknesses, larger deposit densities, different deposit morphologies, and higher thermal conductivities.

Preciado, Ignacio [University of Utah; Eddings, Eric G. [University of Utah; Sarofim, Adel F. [University of Utah; Dinwiddie, Ralph Barton [ORNL; Porter, Wallace D [ORNL; Lance, Michael J [ORNL

2009-01-01

362

Advanced deposition model for thermal activated chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Thermal Activated Chemical Vapor Deposition (TACVD) is defined as the formation of a stable solid product on a heated substrate surface from chemical reactions and/or dissociation of gaseous reactants in an activated environment. It has become an essential process for producing solid film, bulk material, coating, fibers, powders and monolithic components. Global market of CVD products has reached multi billions dollars for each year. In the recent years CVD process has been extensively used to manufacture semiconductors and other electronic components such as polysilicon, AlN and GaN. Extensive research effort has been directed to improve deposition quality and throughput. To obtain fast and high quality deposition, operational conditions such as temperature, pressure, fluid velocity and species concentration and geometry conditions such as source-substrate distance need to be well controlled in a CVD system. This thesis will focus on design of CVD processes through understanding the transport and reaction phenomena in the growth reactor. Since the in situ monitor is almost impossible for CVD reactor, many industrial resources have been expended to determine the optimum design by semi-empirical methods and trial-and-error procedures. This approach has allowed the achievement of improvements in the deposition sequence, but begins to show its limitations, as this method cannot always fulfill the more and more stringent specifications of the industry. To resolve this problem, numerical simulation is widely used in studying the growth techniques. The difficulty of numerical simulation of TACVD crystal growth process lies in the simulation of gas phase and surface reactions, especially the latter one, due to the fact that very limited kinetic information is available in the open literature. In this thesis, an advanced deposition model was developed to study the multi-component fluid flow, homogeneous gas phase reactions inside the reactor chamber, heterogeneous surface reactions on the substrate surface, conductive, convective, inductive and radiative heat transfer, species transport and thereto-elastic stress distributions. Gas phase and surface reactions are studied thermodynamically and kinetically. Based on experimental results, detailed reaction mechanisms are proposed and the deposition rates are predicted. The deposition model proposed could be used for other experiments with similar operating conditions. Four different growth systems are presented in this thesis to discuss comprehensive transport phenomena in crystal growth from vapor. The first is the polysilicon bulk growth by modified Siemens technique in which a silicon tube is used as the starting material. The research effort has been focused on system design, geometric and operating parameters optimization, and heterogeneous and homogeneous silane pyrolysis analysis. The second is the GaN thin film growth by iodine vapor phase epitaxy technique. Heat and mass transport is studied analytically and numerically. Gas phase and surface reactions are analyzed thermodynamically and kinetically. Quasi-equilibrium and kinetic deposition models are developed to predict the growth rate. The third one is the AlN thin film growth by halide vapor phase epitaxy technique. The effects of gas phase and surface reactions on the crystal growth rate and deposition uniformity are studied. The last one is the AlN sublimation growth system. The research effort has been focused on the effect of thermal environment evolution on the crystal growth process. The thermoelastic stress formed in the as-grown AlN crystal is also calculated.

Cai, Dang

363

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...

364

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...

365

Numerical Modeling of Ice Deposition  

Microsoft Academic Search

A method of computing the rate of growth of ice crystals by deposition is described. Predictions of growth characteristics over the temperature range of 1 through 35C are shown and compared with meager experimental data available within this temperature range.The growth rate equations are based on Fick's law of diffusion. In applying this law to nonspherical ice crystals, the analogy

L. R. Koenig

1971-01-01

366

Titania Deposition on PMR-15.  

National Technical Information Service (NTIS)

The formation, degree of crystallinity and adherence of dense titania (TiO(sub 2)) thin film coatings on a high-temperature polyimide resin (PMR-15) can be influenced by chemical composition of the polymer surface. Furthermore, solution deposition conditi...

H. Pizema O. Gershevitz X. Milhet A. McIlwain M. R. DeGuire

2005-01-01

367

Electrophoretic deposition of carbon nanotubes  

Microsoft Academic Search

Electrophoretic deposition (EPD) has been gaining increasing interest as an economical and versatile processing technique for the production of novel coatings or films of carbon nanotubes (CNTs) on conductive substrates. The purpose of the paper is to present an up-to-date comprehensive overview of current research progress in the field of EPD of CNTs. The paper specifically reviews the preparation and

Aldo R. Boccaccini; Johann Cho; Judith A. Roether; Boris J. C. Thomas; E. Jane Minay; Milo S. P. Shaffer

2006-01-01

368

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.

369

Titania Deposition on PMR-15  

NASA Technical Reports Server (NTRS)

The formation, degree of crystallinity and adherence of dense titania (TiO2) thin film coatings on a high-temperature polyimide resin (PMR-15) can be influenced by the chemical composition of the polymer surface. Furthermore, solution deposition conditions can be adjusted to provide additional control over the morphology and crystallinity of the titania films. Recipes for solution-based titania deposition that used a slowly-hydrolyzing titanium fluoride salt in the presence of boric acid as a fluoride scavenger allowed growth of films up to 750 nm thick in 22 h. By adjusting solution pH and temperature, either amorphous titania or oriented crystalline anatase films could be formed. Surface sulfonate groups enhance the adhesion of solution-deposited oxide thin film coatings. While most sulfonation procedures severely damaged the PMR-15 surface, the use of chlorosulfonic acid followed by hydrolysis of the installed chlorosulfonyl groups provided effective surface sulfonation without significant surface damage. In some cases, the oxide deposition solution caused partial hydrolysis of the polymer surface, which itself was sufficient to allow adhesion of the titania film through chelation of titanium ions by exposed benzoic acid groups on the polymer surface.

Meador, Mary B.; Sutter, James K.; Pizem, Hillel; Gershevitz, Olga; Goffer, Yossi; Frimer, Aryeh A.; Sukenik, Chaim N.; Sampathkumaran, Uma; Milhet, Xavier; McIlwain, Alan

2005-01-01

370

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...

371

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...

372

Acoustic wave electroless deposition monitor  

Microsoft Academic Search

A new type of electroless deposition monitor has been constructed from a monolithic acoustic wave device utilizing plate modes with shear displacement components. This device, which operates at 158 MHz, provides a highly accurate means of measuring mass changes (1 ng sq cm) accompanying electrochemical reactions. The acoustic wave, in the form of a plate mode, is launched by applying

A. J. Ricco; S. J. Martin

1987-01-01

373

Electrochemical Deposition Of Conductive Copolymers  

NASA Technical Reports Server (NTRS)

Experiments show electrically conductive films are deposited on glassy carbon or indium tin oxide substrates by electrochemical polymerization of N-{(3-trimethoxy silyl) propyl} pyrrole or copolymerization with pyrrole. Copolymers of monomer I and pyrrole exhibit desired electrical conductivity as well as desired adhesion and other mechanical properties. When fully developed, new copolymerization process useful in making surface films of selectable conductivity.

Nagasubramanian, Ganesan; Distefano, Salvador; Liang, Ranty H.

1991-01-01

374

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

375

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

376

Stratiform Chromite Deposit Model. Chapter E of Mineral Deposit Model for Resource Assessment.  

National Technical Information Service (NTIS)

A new descriptive stratiform chromite deposit model was prepared which will provide a framework for understanding the characteristics of stratiform chromite deposits worldwide. Previous stratiform chromite deposit models developed by the U.S. Geological S...

N. M. Piatak R. D. Taylor R. F. Schulte R. R. Seal

2010-01-01

377

Depositional sequences in clastic continental slope deposits, Gulf of Mexico  

USGS Publications Warehouse

Tertiary and Quaternary sediments, overlying diapiric older Tertiary shales and Louann Salt on the continental slope in the western Gulf of Mexico, show cyclicity based on seismic-reflection patterns. A set of indistinct parallel reflections or an acoustically semi-transparent zone, normally onlapping onto diapir flanks, alternates with a set of distinct parallel reflections that drape the sea bottom. The indistinct reflections represent deposits employed by bottom transport during a lowering of sea level. Sea level rise and hight stand are characterized by hemipelagic sediments that form blanket-type deposits. Differential sediment loading causes diapiric activity that may reach maximum upward velocities when sea level rises. ?? 1981 A.M. Dowden, Inc.

Bouma, A. H.

1981-01-01

378

First indication of Vedde-Ash deposits in the Trondheimsfjord area, mid-Norway  

NASA Astrophysics Data System (ADS)

Ash-layers that were deposited shortly after land surface became ice-free are very useful geochronological time markers in sediment sequences, especially when other dating techniques fail or give ambiguous ages. Here we present a geochemical, sedimentological and geophysical data set from an ash-layer found in a lake sediment sequence in Trondheim area, coastal mid-Norway. The geographical position of the lake outside the prominent Tautra and Hoklingen moraine system and its elevation above the local marine limit enabled lacustrine conditions and the onset of sedimentation shortly after local deglaciation at about 12.7 kyr BP. The sediment succession recovered is 590 cm long and can be divided into a minerogenic basal part followed by a biogenic section towards the top. Within the homogeneous, soft sediments of the minerogenic section a distinct, 1.5-cm-thick layer of coarser sediment occurs. Textures and geochemistry of single grains revealed rhyolitic and basaltic compositions demonstrating a volcanic origin. Furthermore, detailed geochemical analyses and comparison with known Late Pleistocene and early Holocene ash layers revealed a geochemical composition similar to 'Vedde-ash' particles of the Icelandic Katla volcanic system. The 'Vedde-ash' layer is known from various archives around the Nordic Seas, i.e. the British Islands, the Faeroe Islands, the west Norwegian coast and from single grains in a peat bog on the Lofoten Islands. In addition to the volcanic glass shards, high-resolution XRF scanning from split-core surfaces revealed elevated plateaus of various elements such as titanium, zirconium, strontium, manganese and sulphur below and/or above the specific ash layer that exceed the natural background of soft, minerogenic sediments. Although independent indicators are recommended these elevated plateaus suggest either a volcanic event of longer duration than previously anticipated or very high sedimentation rates within the ash fall-out period. Especially the enrichment of sulphur above the specific ash layer may indicate a pronounced aftermath and unknown environmental feedback processes to this fall-out event. The ash layer identification in Trondheimsfjord area extends the occurrence of this fall-out event to coastal mid-Norway.

Klug, M.; Tegner, C.; Zimmermann, H.-D.; Piotrowski, J. A.; Stolz, K.; Knies, J.

2012-04-01

379

Computational study of wax deposition in pipeline  

NASA Astrophysics Data System (ADS)

Wax deposition in subsea pipelines is one of the flow assurance problems for oil and gas production. In contrast to many studies about single phase wax deposition, gas-oil wax deposition studies are very limited. The wax deposition mechanism and model prediction are restricted by many factors such as hydrodynamic and thermal when multiphase flow is involved. Wax deposition modeling becomes complicated under multiphase flowing conditions. wax deposition is depended by the flow pattern. The stratified flow is one of the most common flow patterns in the actual subsea gas-oil flowing conditions. In this work, numerical methods are used to study wax deposition in oil-gas stratified flow through a pipe. Based on the flow analysis about stratified flow, the non-isothermal heat and mass transfer is calculated. The temperature profile of the oil and the concentration profile of wax in oil are obtained. The change of the oil-gas interface i.e. the liquid holdup throughout the pipe must be taken into the heat and mass balance. The valid wax deposition surface must be taken into the wax deposition modeling by establishing function of the liquid holdup and the wetted area by oil. The molecular diffusion is as the deposition mechanism. The increase of the wax fraction in the deposit as a function of time depends on the mass flux from the oil deposit interface into the gel and the growth of the deposit thickness depends on the difference between the mass flux from the bulk oil to the oil deposit interface and the mass flux from the interface into the deposit. In addition, the growth of the wax deposit as a function of time along with the effect oil flow rate, gas flow rate and the inlet temperature are discussed. The presence of gas significantly reduces the severity of wax deposition by altering the heat and mass transfer characteristics.

Duan, Jimiao; Gong, Jing; Liu, Huishu

2013-07-01

380

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...

381

(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

382

MAPLE deposition of biomaterial multilayers  

NASA Astrophysics Data System (ADS)

Double layers of polyethylene glycol (PEG) and 3-(3,4-dihydroxyphenyl)-2-methyl- L-alanine (m-DOPA) thin films were obtained by matrix assisted pulsed laser evaporation (MAPLE) technique, by depositing a first layer of m-DOPA on Si substrate and a second layer of PEG on top of it. The films were characterized by low angle X-ray diffraction (LAXRD), X-ray reflectivity (XRR), atomic force microscopy (AFM), and micro-Raman spectroscopy. From these analyses it resulted that PEG was deposited without any relevant damage both in terms of chemical structure and molecular weight. Furthermore, PEG chains were mostly in the extended conformation, although PEG micelles appeared.

Califano, Valeria; Bloisi, Francesco; Vicari, Luciano R. M.; Colombi, Paolo; Bontempi, Elza; Depero, Laura E.

2008-09-01

383

The unending deposit insurance mess.  

PubMed

The thrift institution deposit insurance mess is rooted in defects in political and bureaucratic accountability. Under existing incentives, covering up evidence of poor regulatory performance and relaxing binding capital requirements are rational governmental responses to widespread industry insolvency. Similarly, aggressive industry risk taking is a rational response by thrift managers to regulatory forbearances. Far from acknowledging these incentive defects, the Bush plan for cleaning up the mess adopts theories that spotlight other causes: specifically, poor thrift management and the deregulation of thrift institution activities and of deposit interest rates. To end the mess, politicians and regulators must jettison these comfortable theories and surrender discretion that permits them to finesse the need to budget for governmental financial commitments. PMID:17788695

Kane, E J

1989-10-27

384

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

385

Deposit formation in hydrocarbon fuels  

Microsoft Academic Search

A high-pressure fuel coking test apparatus was designed and developed and was used to evaluate thermal decomposition (coking) limits and carbon deposition rates in heated copper tubes for two hydrocarbon fuels, RP-1 and commercial grade propane. Tests were also conducted using JP-7 and chemically-pure propane as being representative of more refined cuts of the baseline fuels. A parametric evaluation of

R. Roback; L. J. Spadaccini; E. J. Szetela

1983-01-01

386

Thermal Plasma Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

Diamond has many unrivaled properties and has great application potentials in modern industry. Among various metastable chemical vapor deposition methods for producing diamond, thermal plasma chemical vapor deposition has shown advantages of offering high growth rates and high quality. However, systematic parametric studies are needed for optimization of the process. This study investigates the effects of substrate materials, substrate temperatures, substrate pre-treatment methods, precursor concentrations, and process pressures on the initial nucleation, growth rate, morphology, and quality of the diamond films under thermal plasma conditions. X-ray diffraction, optical microscopy, scanning electron microscopy, and Raman spectroscopy have been used for the diamond film characterization. Thermal plasmas have been also used to deposit homoepitaxial diamond films at high growth rates. High quality macro-sized diamond crystals have been grown on {100} and {110} oriented natural type IIa diamond seeds. Raman spectra reveal that the diamond deposit is of high quality. Laue X-ray diffraction patterns show that the diamond grown on the seed is single crystal and oriented epitaxially with the underlying seed crystal. The gas phase chemistry has been calculated using computer code SOLGASMIX to determine the equilibrium gaseous composition in thermal plasmas. Key species concentrations have been obtained under various pressure conditions. Although kinetic factors have not been taken into account, equilibrium conditions offer an estimation of the process justified by the "frozen chemistry" associated with the fast quenching in the boundary layer. Due to the strong emission of the highly luminous plasma plumes, it has been difficult to measure the in -situ substrate temperature distribution with conventional infrared optical pyrometers. A new technique has been developed to obtain the surface temperature distribution of the substrate by combining the experimental temperature measurements of an array of thermocouples imbedded in the substrate and analytical solutions of the two-dimensional heat conduction equation. This method enables an indirect determination of the substrate temperature distribution.

Lu, Zhipeng

387

Pele Plume Deposit on Io  

NASA Technical Reports Server (NTRS)

The varied effects of Ionian volcanism can be seen in this false color infrared composite image of Io's trailing hemisphere. Low resolution color data from Galileo's first orbit (June, 1996) have been combined with a higher resolution clear filter picture taken on the third orbit (November, 1996) of the spacecraft around Jupiter.

A diffuse ring of bright red material encircles Pele, the site of an ongoing, high velocity volcanic eruption. Pele's plume is nearly invisible, except in back-lit photographs, but its deposits indicate energetic ejection of sulfurous materials out to distances more than 600 kilometers from the central vent. Another bright red deposit lies adjacent to Marduk, also a currently active ediface. High temperature hot spots have been detected at both these locations, due to the eruption of molten material in lava flows or lava lakes. Bright red deposits on Io darken and disappear within years or decades of deposition, so the presence of bright red materials marks the sites of recent volcanism.

This composite was created from data obtained by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. The region imaged is centered on 15 degrees South, 224 degrees West, and is almost 2400 kilometers across. The finest details that can be discerned in this picture are about 3 kilometers across. North is towards the top of the picture and the sun illuminates the surface from the west.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

1997-01-01

388

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

389

29 CFR 2200.56 - Depositions.  

Code of Federal Regulations, 2010 CFR

...deposition shall be identified on camera at the commencement of the deposition...be videotaped. Identification on camera of each witness, attorney, and...accurate video recording. Lighting, camera angle, lens setting, and field of view...

2009-07-01

390

29 CFR 2200.56 - Depositions.  

Code of Federal Regulations, 2010 CFR

...deposition shall be identified on camera at the commencement of the deposition...be videotaped. Identification on camera of each witness, attorney, and...accurate video recording. Lighting, camera angle, lens setting, and field of view...

2010-07-01

391

Detection of Outgassing in Electroplated Tin Deposits.  

National Technical Information Service (NTIS)

The outgassing characteristics of matte deposits from generic bright acid tin baths which are operated to produce matte deposits are very similar to the outgassing characteristics of bright acid tin. Methods are proposed to differentiate between true matt...

W. T. Hobson

1982-01-01

392

Surficial Deposits in the Bear Lake Basin.  

National Technical Information Service (NTIS)

Mapping and dating of surficial deposits in the Bear Lake drainage basin were undertaken to provide a geologic context for interpretation of cores taken from deposits beneath Bear Lake, which sometimes receives water and sediment from the glaciated Bear R...

M. C. Reheis B. J. C. Laabs R. M. Forester J. P. McGeehin D. S. Kaufman J. Bright

2005-01-01

393

Micromachines Acoustic Sensors for Monitoring Electrochemical Deposition.  

National Technical Information Service (NTIS)

Disclosed are micromachined acoustic sensors for monitoring electrochemical deposition, methods for fabricating such sensors, and methods for in-situ monitoring of electrochemical deposition processes using such sensors. An exemplary acoustic sensor compr...

F. R. Williams G. S. May

2005-01-01

394

CPP-GMR Films With Oblique Deposition  

Microsoft Academic Search

We investigated current perpendicular-to-the-plane giant magnetolresistive (CPP-GMR) films deposited with oblique incidence. The obliquely deposited free layer increased the MR ratio and the RA slightly, even though small asymmetric distribution of tilted angles was seen in our cross-sectional observation. In contrast, the MR ratio decreased with the obliquely deposited Cu spacer. Therefore, oblique deposition for CPP-GMR films is an effective

Hiroyuki Hoshiya; Katsumi Hoshino

2006-01-01

395

Wind Tunnel Modeling of Small Particle Deposition  

Microsoft Academic Search

An inexpensive microsphere dispersion, deposition, and sampling system is described. This system was used to examine the transport and deposition of small particles (? 1 ?m diameter) across the aerodynamic boundary layer which developed over a prototype deposition surface (smooth, flat, acrylic plate). Unit density, polystyrene latex microspheres (0.8 and 1.1 ?m diameter) were deposited onto both oil-coated and dry,

D. I. McCready

1986-01-01

396

PENECONCORDANT URANIUM DEPOSIT-A PROPOSED TERM  

Microsoft Academic Search

Peneconcordant uranium deposits cover a widespread and important type of ; uranium deposits that have a common and distinctive form, namely, nearly ; concordant to the bedding of the host rock. The term describes the form of the ; numerous and highly productive uranium deposits in sedimentary rocks of the ; Colorado Plateau, Wyoming, North and South Dakota, and Texas.

W. I. Finch

1959-01-01

397

The Legal Deposit of Electronic Publications.  

ERIC Educational Resources Information Center

Discusses electronic publication and legal deposit (the requirement that publications produced within a certain jurisdiction be deposited, usually in designated libraries which include the national library). The need for extension of deposit requirements to electronic materials, issues of concern, current legislation worldwide, and the role of…

Vickery, Jim

1998-01-01

398

ATMOSPHERIC DEPOSITION MODELING AND MONITORING OF NUTRIENTS  

EPA Science Inventory

This talk presents an overview of the capabilities and roles that regional atmospheric deposition models can play with respect to multi-media environmental problems. The focus is on nutrient deposition (nitrogen). Atmospheric deposition of nitrogen is an important contributor to...

399

Genetics Home Reference: Dense deposit disease  

MedlinePLUS

... II to refer to dense deposit disease. How common is dense deposit disease? Dense deposit disease is very rare, affecting 2 ... the condition? Why are some genetic conditions more common in particular ethnic groups? ... bacteria ; diabetes ; diabetes mellitus ; end-stage renal ...