Formation of lacustrine plains in west-central Alaska as a result of permafrost degradation and aggradation

NASA Astrophysics Data System (ADS)

Kanevskiy, M. Z.; Jorgenson, M. T.; Shur, Y.; O'Donnell, J.; Harden, J. W.; Fortier, D.

2012-12-01

Perennially frozen lacustrine sediments containing a large amount of ground ice comprise a significant part of the upper permafrost of the lowlands of west-central Alaska, including Koyukuk Flats and Innoko Flats. Study sites are located in the discontinuous permafrost zone, where permafrost was encountered mainly within uplifted peat plateaus. The upper part of studied sections is formed by frozen peat up to 3 m thick underlain by lacustrine silt, which is mostly ice-rich. Cryogenic structure of lacustrine sediments at different sites has common features: (1) prevalence of layered, braided, and reticulate cryostructures; (2) high variability in the ice content of sediments; (3) high density and low water content of soil aggregates separated by ice lenses. Volume of visible ice in silt reaches at places 40% and more. The thickness of ice lenses generally varies from 1 to 5 cm and occasionally reaches 10 cm. Remnants of peat plateaus are surrounded by unfrozen bogs and fens, formed as a result of thawing and settling of ice-rich lacustrine silt. Modern thermokarst scars initially form at places where ice-rich silt is not protected by a thick layer of organic material. Further development of thermokarst bogs includes lateral enlargement of thaw bulbs and collapsing of the margins of peat plateaus. Lacustrine silt within taliks is covered by woody peat accumulated under forests during the stage of permafrost plateau formation and then by aquatic sphagnum peat accumulated in taliks after collapse. We relate the formation of ice-rich lacustrine sediments to development of lake thermokarst, which affected ice-rich silty yedoma deposits during the transition from Pleistocene to Holocene. Terrain development in lacustrine lowlands of west-central Alaska includes five stages related to permafrost aggradation and degradation from the late Pleistocene to the present time: 1) formation of the ice-rich syngenetic permafrost (yedoma) during the late Pleistocene; 2) yedoma degradation in the yearly Holocene and formation of thaw lakes; 3) complete yedoma degradation under thaw lakes and refreezing of thawed sediments at elevated areas; 4) peat accumulation and freezing of sediments in thaw lake basins; and 5) new cycle of thermokarst and formation of taliks under thaw lakes, bogs and fens. Stages of terrain development of lacustrine lowlands since the Late Pleistocene

Experimental Investigation of the Deepening of the Combustion Front into Peat Layers Different in Botanical Composition

NASA Astrophysics Data System (ADS)

Kasymov, D. P.

2017-01-01

The deepening of the center of combustion into peat layers of different botanical compositions (pine-cotton grass and grass-sphagnum peats), typical for the Tomsk region, was investigated experimentally. Peats were ignited from a model ground forest fire initiated by firing of a needle-litter layer. As a result of laboratory investigations, the change in the temperature in the bulk of peat samples with time was determined and analyzed, and the rates of their combustion in the horizontal and vertical directions were estimated. It was established that a fire penetrates deep into a layer of grass-sphagnum peat, containing more than 70% of combustion conductors in its composition, more rapidly as compared to that of pine-cotton grass peat. The rates of combustion of grass-sphagnum peat in the vertical and horizontal directions are larger by 20 and 22%, respectively, than those of pine-cotton grass peat, which is evidently due to the botanical composition of grass-sphagnum peat and the random arrangement of components in its layers.

Retention of atmospheric Cu, Ni, Cd and Zn in an ombrotrophic peat profile near the Outokumpu Cu-Ni mine, SE-Finland

NASA Astrophysics Data System (ADS)

Rausch, N.; Nieminen, T. M.; Ukonmaanaho, L.; Cheburkin, A.; Krachler, M.; Shotyk, W.

2003-05-01

Peat cores taken from ombrotrophic bogs are widely used to reconstruct historical records of atmospheric lead and mercury déposition[1, 2]. In this study, the retention of copper, nickel, cadmium and zinc in peat bogs are studied by comparing high resolution, age dated concentration profiles with emissions from the main local source, the Outokumpu copper-nickel mine. An ombrotrophic peat core was taken from the vicinity of Outokumpu, E Finland. Copper and zinc concentrations of dry peat were measured by XRF, cadmium and nickel by GF-AAS, and sample ages by 210Pb. Only copper and nickel show enhanced concentrations in layers covering the mining period, indicating a retention of these elements. However, the more detailed comparison of ore production rates and concentrations in age-dated samples show clearly that only copper is likely to be permanently fixed, while nickel doesn't reflect the mining activity. Even though copper is retained in the upper part of the profile, a possible redeposition of this element by secondary processes (e.g., water table fluctuations) can not be excluded. This question will be resolved by further investigations, e.g. by pore water profiles.

Geophysical surveying in the Sacramento Delta for earthquake hazard assessment and measurement of peat thickness

NASA Astrophysics Data System (ADS)

Craig, M. S.; Kundariya, N.; Hayashi, K.; Srinivas, A.; Burnham, M.; Oikawa, P.

2017-12-01

Near surface geophysical surveys were conducted in the Sacramento-San Joaquin Delta for earthquake hazard assessment and to provide estimates of peat thickness for use in carbon models. Delta islands have experienced 3-8 meters of subsidence during the past century due to oxidation and compaction of peat. Projected sea level rise over the next century will contribute to an ongoing landward shift of the freshwater-saltwater interface, and increase the risk of flooding due to levee failure or overtopping. Seismic shear wave velocity (VS) was measured in the upper 30 meters to determine Uniform Building Code (UBC)/ National Earthquake Hazard Reduction Program (NEHRP) site class. Both seismic and ground penetrating radar (GPR) methods were employed to estimate peat thickness. Seismic surface wave surveys were conducted at eight sites on three islands and GPR surveys were conducted at two of the sites. Combined with sites surveyed in 2015, the new work brings the total number of sites surveyed in the Delta to twenty.Soil boreholes were made at several locations using a hand auger, and peat thickness ranged from 2.1 to 5.5 meters. Seismic surveys were conducted using the multichannel analysis of surface wave (MASW) method and the microtremor array method (MAM). On Bouldin Island, VS of the surficial peat layer was 32 m/s at a site with pure peat and 63 m/s at a site peat with higher clay and silt content. Velocities at these sites reached a similar value, about 125 m/s, at a depth of 10 m. GPR surveys were performed at two sites on Sherman Island using 100 MHz antennas, and indicated the base of the peat layer at a depth of about 4 meters, consistent with nearby auger holes.The results of this work include VS depth profiles and UBC/NEHRP site classifications. Seismic and GPR methods may be used in a complementary fashion to estimate peat thickness. The seismic surface wave method is a relatively robust method and more effective than GPR in many areas with high clay content or where surface sediments have been disturbed by human activities. GPR does however provide significantly higher resolution and better depth control in areas with suitable recording conditions.

Facies development in the Lower Freeport coal bed, west-central Pennsylvania, U.S.A.

USGS Publications Warehouse

Pierce, B.S.; Stanton, R.W.; Eble, C.F.

1991-01-01

The Lower Freeport coal bed in west-central Pennsylvania is interpreted to have formed within a lacustrine-mire environment. Conditions of peat formation, caused by the changing chemical and physical environments, produced five coal facies and two mineral-rich parting facies within the coal bed. The coal bed facies are compositionally unique, having developed under varying conditions, and are manifested by megascopic, petrographic, palynologic and quality characteristics. The initial environment of the Lower Freeport peat resulted in a coal facies that is relatively high in ash yield and contains large amounts of lycopod miospores and moderate abundances of cryptotelinite, crypto-gelocollinite, inertinite and tree fern miospores. This initial Lower Freeport peat is interpreted to have been a topogenous body that was low lying, relatively nutrient rich (mesotrophic to eutrophic), and susceptible to ground water and to sediment influx from surface water. The next facies to form was a ubiquitous, clay-rich durain parting which is attributed to a general rise in the water table accompanied by widespread flooding. Following formation of the parting, peat accumulation resumed within an environment that inhibited clastic input. Development of doming in this facies restricted deposition of the upper shale parting to the margins of the mire and allowed low-ash peat to form in the interior of the mire. Because this environment was conducive to preservation of cellular tissue, this coal facies also contains large amounts of crypto-telinite. This facies development is interpreted to have been a transitional phase from topogenous, planar peat formation to slightly domed, oligotrophic (nutrient-poor) peat formation. As domed peat formation continued, fluctuations in the water table enabled oxidation of the peat surface and produced high inertinite concentrations toward the top of the coal bed. Tree ferns became an increasingly important peat contributor in the e upper facies, based on the palynoflora. This floral change is interpreted to have resulted from the peat surface becoming less wet or better drained, a condition that inhibited proliferation of lycopod trees. Accumulation of the peat continued until rising water levels formed a freshwater lake within which clays and silts were deposited. The development of the Lower Freeport peat from a planar mire through transitional phases toward domed peat formation may be an example of the type of peat formation of other upper Middle and Upper Pennsylvanian coal beds. ?? 1991.

Degradation potentials of dissolved organic carbon (DOC) from thawed permafrost peat

PubMed Central

Panneer Selvam, Balathandayuthabani; Lapierre, Jean-François; Guillemette, Francois; Voigt, Carolina; Lamprecht, Richard E.; Biasi, Christina; Christensen, Torben R.; Martikainen, Pertti J.; Berggren, Martin

2017-01-01

Global warming can substantially affect the export of dissolved organic carbon (DOC) from peat-permafrost to aquatic systems. The direct degradability of such peat-derived DOC, however, is poorly constrained because previous permafrost thaw studies have mainly addressed mineral soil catchments or DOC pools that have already been processed in surface waters. We incubated peat cores from a palsa mire to compare an active layer and an experimentally thawed permafrost layer with regard to DOC composition and degradation potentials of pore water DOC. Our results show that DOC from the thawed permafrost layer had high initial degradation potentials compared with DOC from the active layer. In fact, the DOC that showed the highest bio- and photo-degradability, respectively, originated in the thawed permafrost layer. Our study sheds new light on the DOC composition of peat-permafrost directly upon thaw and suggests that past estimates of carbon-dioxide emissions from thawed peat permafrost may be biased as they have overlooked the initial mineralization potential of the exported DOC. PMID:28378792

Bringing back the rare - biogeochemical constraints of peat moss establishment in restored cut-over bogs

NASA Astrophysics Data System (ADS)

Raabe, Peter; Blodau, Christian; Hölzel, Norbert; Kleinebecker, Till; Knorr, Klaus-Holger

2016-04-01

In rewetted cut-over bogs in north-western Germany and elsewhere almost no spontaneous recolonization of hummock peat mosses, such as Sphagnum magellanicum, S. papillosum or S. rubellum can be observed. However, to reach goals of climate protection every restoration of formerly mined peatlands should aim to enable the re-establishment of these rare but functionally important plant species. Besides aspects of biodiversity, peatlands dominated by mosses can be expected to emit less methane compared to sites dominated by graminoids. To assess the hydrological and biogeochemical factors constraining the successful establishment of hummock Sphagnum mosses we conducted a field experiment by actively transferring hummock species into six existing restoration sites in the Vechtaer Moor, a large peatland complex with active peat harvesting and parallel restoration efforts. The mosses were transferred as intact sods in triplicate at the beginning of June 2016. Six weeks (mid-July) and 18 weeks later (beginning of October) pore water was sampled in two depths (5 and 20 cm) directly beneath the inoculated Sphagnum sods as well as in untreated control plots and analysed for phosphate, ferrous iron, ammonia, nitrate and total organic carbon (TOC). On the same occasions and additionally in December, the vitality of mosses was estimated. Furthermore, the increment of moss height between July and December was measured by using cranked wires and peat cores were taken for lab analyses of nutrients and major element inventories at the depths of pore water sampling. Preliminary results indicate that vitality of mosses during the period of summer water level draw down was strongly negatively related to plant available phosphate in deeper layers of the residual peat. Furthermore, increment of moss height was strongly negatively related to TOC in the upper pore waters sampled in October. Concentration of ferrous iron in deeper pore waters was in general significantly higher beneath Sphagnum sods compared to control plots suggesting a direct impact of hummock mosses on microsite soil moisture conditions. However, with an increase of water levels towards winter season accompanied by increase of ferrous iron and concurrent increase of phosphate in pore waters of the upper peat layers the vitality was strongly positively related to plant available phosphate. This suggests that actively transferred hummock mosses suffering temporarily from desiccation during the dry summer season are able to recover also under relatively higher trophic conditions as long as water level and redox state favour an optimal supply of required water nutrients.

Functioning of microbial complexes in aerated layers of a highmoor peat bog

NASA Astrophysics Data System (ADS)

Golovchenko, A. V.; Bogdanova, O. Yu.; Stepanov, A. L.; Polyanskaya, L. M.; Zvyagintsev, D. G.

2010-09-01

Monitoring was carried out using the luminescent-microscopic method of the abundance parameters of different groups of microorganisms in a monolith and in the mixed layers of a highmoor peat bog (oligotrophic residual-eutrophic peat soil) in a year-long model experiment. The increase of the aeration as a result of mixing of the layers enhanced the activity of the soil fungi. This was attested to by the following changes: the increase of the fungal mycelium length by 6 times and of the fungal biomass by 4 times and the double decrease of the fraction of spores in the fungal complex. The response of the fungal complex to mixing was different in the different layers of the peat bog. The maximal effect was observed in the T1 layer and the minimal one in the T2 layer. The emission of CO2 in the mixed samples was 1.5-2 times higher than that from the undisturbed peat samples. In contrast with the fungi, the bacteria and actinomycetes were not affected by the aeration of the highmoor layers.

Subsurface structures and properties of a medium-scale peatland area by means of hydrogeophysical methods

NASA Astrophysics Data System (ADS)

Altdorff, Daniel; van der Kruk, Jan; Bechtold, Michel; Tiemeyer, Bärbel; Huismann, Sander

2013-04-01

Intact peatlands are natural sinks of climate-relevant atmospheric CO2 and they are able to store high amounts of organic carbon (C). In addition, intact peatlands are increasingly important given positive effects on biodiversity, hydrological processes and corresponding management issues. Nevertheless, large parts of peatlands in populated areas were modified by human activity during the last centuries. In Germany, more than 90% of the peatlands are drained, mainly for agricultural use. Due to the recent recognition of the positive effects of intact peatlands, there are presently several initiatives for re-wetting parts of these peatlands. However, a restoration to nearly natural conditions needs an evaluation of the current situation as well as an assessment of the restoration potential. Therefore, soil properties like peat layer thickness, bulk density and moisture content need to be known. Non-invasive hydrogeophysical methods offer the possibility for a time and cost-effective characterization of peatlands. In this study, we investigated a medium-scale peatland area (approximately 35 ha) of the 3000 ha large 'Großes Moor' peatland. We present apparent conductivity (ECa) values obtained from Electromagnetic Induction (EMI) measurements representative for three investigation depths (approximately 0.25, 0.5, and 1m). We selected zones with dissimilar ECa to identify areas where strong changes in the subsoil properties with depth are expected (i.e. shallow peat soil on top of sand). Within these areas, additional measurements were made using Ground Penetration Radar (GPR) and soil sampling was performed. In total, six 30 m long GPR profiles and corresponding common midpoint (CMP) measurements were recorded. Additionally, 15 soil cores were taken down to a depth of 0.9 m in order to obtain peat thickness, water content, pore water EC, bulk density (BD), as well as C and N content. Each core was divided into several 5 to 20 cm thick layers to obtain information on the vertical variation of these soil properties with depth. Our results indicate that the peat layer is generally characterized by lower BD, higher pore water EC, higher C content, and higher water contents compared to the underlying sand layer. Preliminary EMI results indicate a ECa - C content correlation that decreases with EMI investigation depth from 0.25 to 1 m. Regarding all soil core properties, the strongest contrast occurs at the peat-sand interface. This contrast also clearly appears in some of the GPR results. The EMI apparent conductivities are positively correlated with soil water content and peat thickness obtained from the soil cores. Preliminary GPR results confirm an increased thickness of the upper layer in areas with increased ECa values. The EMI results also reveal clear patterns linked over several fields with different land use history that represent natural structures in the subsurface.

Only low methane production and emission in degraded peat extraction sites after rewetting

NASA Astrophysics Data System (ADS)

Agethen, Svenja; Waldemer, Carolin; Knorr, Klaus-Holger

2015-04-01

In Central Europe rewetting of bogs after peat extraction is a wide spread technique to halt secondary aerobic decomposition and to reestablish plant species such as Sphagnum spp. and Eriophorum spp. that initialize accumulation of organic carbon in peat. Before extraction, such sites are often used for agriculture causing the aerobic degradation of peat and mobilization of phosphorus, ammonia, and dissolved organic matter (DOM). In nutrient poor ecosystems such as bogs, additional supply of P and N does not only trigger the establishment of uncharacteristic vegetation but also the formation of more labile plant litter and DOM that is readily degradable. Therefore, after rewetting and the development of anoxic conditions especially in initial stages high methane (CH4) emissions are reported for these systems compared to pristine bogs. Regarding the potential of methane production and emissions we investigated three common practices to prepare extraction fields for restoration (years since rewetting): i) Filling of drainage ditches, passive rewetting (1 site, Altendorfer Moor, Stade, NW-Germany, ca. 20 yr.), ii) Removal of upper 30 cm peat layer, removed peat used for construction of polder dikes (2 sites, Königsmoor, Leer, NW-Germany, 2 and 3 yr.), iii) Removal upper peat layer down to 50 cm grown peat, not extracted peat used as polder walls (2 sites, Benthullener Moor, Wardenburg, NW-Germany, 3 and 7 yr.). In each site two vegetated replicate mesocosms (diam. 30 cm, depth 40 cm) were sampled and placed in a greenhouse from May-October 2014 to maintain the water table at surface level. Pore water concentrations of ions, fermentation products and DOM, DOM electron acceptor capacity (EAC), soil gas concentrations of CO2, CH4 and H2, gas fluxes as well as element composition and organic matter quality of DOM and SOM were analyzed. We found out that practice i) with least efforts of nutrient removal in the peat produced the highest CH4 emissions (3.5 mmol m-2 d-1) although still within the range of northern pristine bogs. Also practice ii) showed still inputs of external nutrients and labile DOM, but CH4 production was not yet developed (0.23 and 0.07 mmol m-2 d-1). Practice iii) was most effective in nutrient removal, but only in the 7 yr. site little methane (in the 3 yr. site 0.025 vs. 0.41 mmol m-2 d-1in the 7 yr. site) was emitted. The emissions were well in accord with soil gas concentrations, maximum values for CH4 in practice i) were 115 μmol L-1, 2-5 μmol L-1 in practice ii) and 0.5 vs. 16 μmol L-1 in practice iii). Only small concentrations of inorganic electron acceptors such as sulfate imply the importance of organic matter as electron acceptor. The results show that restored bogs on former strongly degraded extraction fields do not necessarily act as exceptionally high CH4 sources. Contrary to other findings in early stages of rewetting CH4 emissions can also be very low until other electron acceptors are exhausted and methanogens become effective competitors for substrates which happens in the order of years.

In situ fluidization for peat bed rupture, and preliminary economic analysis.

PubMed

Niven, R K; Khalili, N

2002-11-01

This study concerns in situ fluidization (ISF), a new remediation method with potential application to the remediation of NAPL and heavy metal contaminants, by their release from the fluidized zone generated by a water jet. The present study examines the effect of ISF on layers of peat, of significance owing to its role as an important NAPL and metal contaminant trap. Once trapped, such contaminants are not readily accessible by most remedial methods, due to the low permeability and diffusivity of the peat. A simple tank experiment is used to demonstrate rupture of a peat layer by ISF, with removal of the peat as elutriated fines and segregated peat chunks. The application of ISF in the field is then examined by three field trials in uncontaminated sands, in both saturated and unsaturated conditions. Fluidized depths of up to 1.9 m in the saturated zone (with refusal on a peat layer) and 2.5 m in the unsaturated zone (no refusal) were attained, using a 1.9-m-long, 50 mm diameter jet operated at 5-13 1 s(-1). Pulses of dark turbidity and shell fragments in the effluent indicated the rupture of peat and shelly layers. The experiments demonstrate the hydraulic viability of ISF in the field, and its ability to remove peat-based contaminants. The issues of appropriate jet design and water generation during ISF are discussed, followed by a preliminary economic analysis of ISF relative to existing remediation methods.

Peat fires as source of polycyclic aromatic hydrocarbons in soils

NASA Astrophysics Data System (ADS)

Tsibart, Anna

2013-04-01

Polycyclic aromatic hydrocarbons (PAHs) arrive from pyrogenic sources including volcanism and the combustion of oil products and plant materials. The production of PAHs during the combustion of plant materials was considered in a number of publications, but their results were mainly obtained in laboratory experiments. Insufficient data are available on the hightemperature production of PAHs in environmental objects. For example, natural fires are frequently related to the PAH sources in landscapes, but very little factual data are available on this topic. On Polistovskii reserve (Russia, Pskov region) the soil series were separated depending on the damage to the plants; these series included soils of plots subjected to fires of different intensities, as well as soils of the background plots. The series of organic and organomineral soils significantly differed in their PAH distributions. In this series, the concentration of PAHs in the upper horizons of the peat soils little varied or slightly decreased, but their accumulation occurred at a depth of 5-10 or 10-20 cm in the soils after the fires. For example, in the series of high moor soils, the content of PAHs in the upper horizons remained almost constant; significant differences were observed in the subsurface horizons: from 2 ng/g in the background soil to 70 ng/g after the fire. In the upper horizons of the oligotrophic peat soils under pine forests, the total PAH content also varied only slightly. At the same time, the content of PAHs in the soil series increased from 15 to 90 ng/g with the increasing pyrogenic damage to the plot. No clear trends of the PAH accumulation were recorded in the organomineral soils. The content of PAHs in the soddy-podzolic soil subjected to fire slightly decreased (from 20 to 10 ng/g) compared to the less damaged soil. In peat fires, the access of oxygen to the fire zone is lower than in forest fires. The oxygen deficit acts as a factor of the organic fragments recombination and PAH production; therefore, larger amounts of PAHs are formed in peat fires. In addition, the peat fires occur directly in the soil layer; therefore, larger amounts of the resulting polyarenes remain in the soils of the fire sites. PAHs also can be formed at the heating of organic matter on the areas adjacent to the fire sites. After the combustion of peat in fires, phenanthrene, chrysene, benz[a]pyrene, and tetraphene accumulate in soils. This is mainly the group of 4-nuclear compounds with the participation of 3-nuclear phenanthrene and 5-nuclear benz[a]pyrene. The formation of high-molecular weight compounds like benz[a]pyrene and, in some places, benzo[ghi]perylene is possible during smoldering under a low oxygen supply.

AmeriFlux US-Snd Sherman Island

DOE Data Explorer

Baldocchi, Dennis [University of California, Berkeley

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-Snd Sherman Island. Site Description - The Sherman Island site is a 38-ha peatland pasture, west of the Delta, that is owned by the state and managed by the California Department of Water Resources. The site is degraded and heavily grazed with ~100 cattle in the area that circumscribes the main field and fetch. The island has been drained and farmed since the late 1800s. The soils of the Delta overlay deep peat that was sequestered over the Holocene period as sea-level rose and flooding of archaic wetlands prevented decomposition of roots and stems. Hence, the upper 10 m of peatland has been lost to decomposition, compaction, and subsidence. Today a mineral soil overlays a peat layer, which coincides with the general depth of the water table.

Biofiltration using peat and a nutritional synthetic packing material: influence of the packing configuration on H2S removal.

PubMed

Dumont, Eric; Cabral, Flavia Da Silva; Le Cloirec, Pierre; Andrès, Yves

2013-01-01

This study aims to evaluate the feasibility of using a nutritional synthetic material (UP20) combined with fibrous peat as a packing material in treating H2S (up to 280 ppmv). Three identical laboratory-scale biofilters with different packing material configurations (peat only; peat + UP20 in a mixture; peat + UP20 in two layers) were used to determine the biofilter performances. The superficial velocity of the polluted gas on each biofilter was 65 m/h (gas flow rate 0.5 Nm3 /h) corresponding to an empty bed residence time = 57 s. Variations in elimination capacity, removal efficiency, temperature and pH were tracked during 111 d. A removal efficiency of 100% was obtained for loading rates up to 6 g/m3/h for the biofilter filled with 100% peat, and up to 10 g/m3/h for both biofilters using peat complemented with UP20. For higher loading rates (up to 25.5 g/m3/h), the configuration ofpeat-UP20 in a mixture provided the best removal efficiencies (around 80% compared to 65% for the configuration of peat-UP20 in two layers and 60% for peat only). Microbial characterization highlighted that peat is able to provide sulfide-oxidizing bacteria. Through kinetic analysis (Ottengrafand Michaelis-Menten models were applied), it appeared that the configuration peat-UP20 in two layers (80/20 v/v) did not show significant improvement compared with peat alone. Although the configuration of peat-UP20 in a mixture (80/20 v/v) offered a real advantage in improving H2S treatment, it was shown that this benefit was related to the bed configuration rather than the nutritional properties of UP20.

Interdependence of peat and vegetation in a tropical peat swamp forest.

PubMed Central

Page, S E; Rieley, J O; Shotyk, W; Weiss, D

1999-01-01

The visual uniformity of tropical peat swamp forest masks the considerable variation in forest structure that has evolved in response to differences and changes in peat characteristics over many millennia. Details are presented of forest structure and tree composition of the principal peat swamp forest types in the upper catchment of Sungai Sebangau, Central Kalimantan, Indonesia, in relation to thickness and hydrology of the peat. Consideration is given to data on peat geochemistry and age of peat that provide evidence of the ombrotrophic nature of this vast peatland and its mode of formation. The future sustainability of this ecosystem is predicted from information available on climate change and human impact in this region. PMID:11605630

Radiometric age dating of peat cores from ombrotrophic bogs: challenges and opportunities presented by the Industrial Period

NASA Astrophysics Data System (ADS)

Shotyk, W.; Appleby, P.; Davies, L. J.; Froese, D. G.; Magnan, G.; Mullan-Boudreau, G.; Noernberg, T.; Bob, S.; van Bellen, S.; Zaccone, C.

2016-12-01

The upper layers of ombrotrophic (rain-fed) bogs are hydrologically isolated from surface waters and groundwaters and, in consequence, contaminants are supplied exclusively from the atmosphere. Peat cores from bogs have been used to reconstruct the history of heavy metal pollution since mining and metallurgy began, but the greatest changes have taken place since the start of the Industrial Revolution which was well underway by the middle of the 19th century. Dating peat, accumulated since this time has been made possible using 210Pb (t1/2 = 22.3 yr), but the validity of the age-depth relationship obtained must always be assessed using one or more chronostratigraphic markers. The post-industrial period provides an enormous range of possible time markers including various fallout radionuclides, numerous trace metals and their isotopes, and countless organic contaminants. Most of these have not yet been explored, and will be helpful only if they are immobile in the peat column; often, their fate during chemical diagenesis in anoxic, acidic bog waters is either unknown or at least poorly understood. The atmospheric bomb pulse curve of 14C for the period since AD 1950 has proved to be particularly valuable for validating 210Pb chronologies by providing accurate dates for individual plant macrofossils. Peat cores collected in northern Alberta, surrounding open pit mines and upgraders of Athabsca Bituminous Sands, were carefully dated using 210Pb and the age-depth relationship evaluated using both 241Am and 14C. The cores nearest industry (MIL, JPH4) show that atmospheric deposition of trace metals has been declining ever since industrial-scale mining and refining began in 1967. This includes all of the potentially toxic trace elements (Ag, Cd, Pb, Sb, Tl), but also the metals known for their enrichment in bitumen (V, Ni, Mo). In fact, the surface layers of these bogs today are comparable in composition to the "cleanest" peat samples ever found in the northern hemisphere. Our findings are completely opposed to recent claims about environmental pollution by metals from mining and upgrading in this region, illustrating the importance of reliable age dates and the value of robust age-depth models.

Dynamics of biochemical processes and redox conditions in geochemically linked landscapes of oligotrophic bogs

NASA Astrophysics Data System (ADS)

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

2016-04-01

The biological activity in oligotrophic peatlands at the margins of the Vasyugan Mire has been studied. It is shown found that differently directed biochemical processes manifest themselves in the entire peat profile down to the underlying mineral substrate. Their activity is highly variable. It is argued that the notion about active and inert layers in peat soils is only applicable for the description of their water regime. The degree of the biochemical activity is specified by the physical soil properties. As a result of the biochemical processes, a micromosaic aerobic-anaerobic medium is developed under the surface waterlogged layer of peat deposits. This layer contains the gas phase, including oxygen. It is concluded that the organic and mineral parts of peat bogs represent a single functional system of a genetic peat profile with a clear record of the history of its development.

Holocene Depositional History of Shad Pond, a Hypersaline Coastal Lagoon, Eleuthera, Bahamas and Its Influence on Lucayan Occupation

NASA Astrophysics Data System (ADS)

Boush, L. E.; Fentress, S.; Conroy, M.; Cook, A.; Miseridina, D.; Buynevich, I. V.; Myrbo, A.; Brown, E. T.; Berman, M.; Gnivecki, P.; Kjellmark, E.; Savarese, M.; Brady, K.

2013-12-01

Shad Pond, an enclosed hypersaline lagoon on the southeastern tip of Eleuthera, Bahamas reveals a ~5000-year record of hurricane activity, as well as sea-level and climate change history. Three sediment cores recovered 1.04-2.54 m of sediment over bedrock along a transect perpendicular to shoreline. Sediment composition and grain size, loss on ignition, X-ray fluorescence (XRF) measurements of the cores along with dune transects and ground-penetrating radar (GPR) profiles adjacent to the lake provide a comprehensive dataset to interpret the history of this coastal basin. The sedimentary sequence was composed of alternating lithofacies that included microbial mats, sand, and peat. Laminated mats often alternated with sandy layers in thin to medium-bedded units. Two peat layers were found in the basal part of the shore-distal core (Site 1) between 1.82-2.40 m and 2.53-2.54 m and were separated by a 13-cm-thick gray mud layer. In general, organic matter and carbonate content tracked granulometry and composition in all cores. High-resolution XRF scans of Ca and Sr at Site 1 show elevated levels ~3,700 cal yBP, which correlate with the top of the peat layer, but these elemental concentrations vary at Site 3. XRF measurements of Fe indicate a dust flux that has been recorded regionally throughout the Caribbean. Dune transects and GPR profiles indicate a phased history of the pond, beginning with initial stages as an open lagoon dominated by red mangrove, with black mangrove and buttonwood also present. The lake likely closed at approximately 3,700 cal yBP indicated by the transition between the upper peat and microbial mat layers. This could have been due to increased storm events in a regime of rising sea level. Aeolian aggradation continued to heighten the barrier between the bedrock headlands to its present position. Hurricane overwash deposits punctuated the algal mat accumulation throughout this time period. Present-day hypersaline conditions sustain algal mats throughout the lake bottom. It is likely that the occupation by Lucayan culture was influenced by the position of the shoreline along southern Eleuthera and this lake was already unsuitable as a water source at the time of their arrival and occupation during 1300-600 years BP (AD 700-1400).

The Effects of Light Intensity, Casing Layers, and Layering Styles on Royal Sun Medicinal Mushroom, Agaricus brasiliensis (Higher Basidiomycetes) Cultivation in Turkey.

PubMed

Adanacioglu, Neşe; Boztok, Kaya; Akdeniz, Ramazan Cengiz

2015-01-01

The aim of this research is to evaluate the effects of light intensity, casing layers, and layering styles on the production of the culinary-medicinal mushroom Agaricus brasiliensis in Turkey. The experiments were designed in split-split plots and replicated twice. Three different light intensities-I1, 350 lux; I2, 450 lux; and I3, 750 lux-were used in main plots as environmental factors. A mixture of 4 different casing layers- peat (100%), peat-perlite (75%:25%), peat-clinoptilolite (75%:25%), and peat-perlite-clinoptilolite (60%:20%:20%)-were used at split plots and at split plots. S1, a flat, 3-cm casing layer; S2, a flat, 5-cm casing layer; and S3, casing soil ridges 10 cm wide × 4 cm high, 10 cm apart, were deposited on top of 1-cm overall soil casing layers. At the end of the harvest phase, the total yield was estimated per 100 kg of substrate. Biological efficiency (percentage) was determined from the fresh weight of the mushrooms and the dry weight of the compost at the end of the harvesting period. The highest total yield (7.2 kg/100 kg compost) and biological efficiency (27.63%) were achieved from I2 × peat-perlite-clinoptilolite × S2 treatment. Influence of light intensity, casing layer, layering style, and their interaction in treatments with color values (L*, a*, b*, chroma*, and hue*) also were examined. It has been shown that within color values, chroma* (saturation) values of mushroom caps were affected by light intensity, casing layer, and layering style treatments and light intensity × casing layer treatments and the brightness of mushroom caps tended to increase as light intensity increased.

Biodegradation of high doses of commercial pesticide products in pilot-scale biobeds using olive-oil agroindustry wastes.

PubMed

Delgado-Moreno, L; Nogales, R; Romero, E

2017-12-15

Biobeds systems containing soil, peat and straw (SPS) are used worldwide to eliminate pesticide point-source contamination, but implantation is difficult when peat and/or straw are not available. Novel biobeds composed of soil, olive pruning and wet olive mill cake (SCPr) or its vermicompost (SVPr) were assayed at pilot scale for its use in olive grove areas. Their removal efficiency for five pesticides applied at high concentration was compared with the biobed with SPS. The effect of a grass layer on the efficiency of these biobeds was also evaluated. Pesticides were retained mainly in the upper layer. In non-planted biobeds with SCPr and SVPr, pesticides dissipation was higher than in SPS, except for diuron. In the biobed with SVPr, with the highest pesticide dissipation capacity, the removed amount of dimethoate, imidacloprid, tebuconazole, diuron and oxyfluorfen was 100, 80, 73, 75 and 50%, respectively. The grass layer enhanced dehydrogenase and diphenol-oxidase activities, modified the pesticides dissipation kinetics and favored the pesticide downward movement. One metabolite of imidacloprid, 3 of oxyfluorfen and 4 of diuron were identified by GC-MS. These novel biobeds represent an alternative to the traditional one and a contribution to promote a circular economy for the olive-oil production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Potential Sedimentary Evidence of Two Closely Spaced Tsunamis on the West Coast of Aceh, Indonesia

NASA Astrophysics Data System (ADS)

Monecke, Katrin; Meilianda, Ella; Rushdy, Ibnu; Moena, Abudzar; Yolanda, Irvan P.

2016-04-01

Recent research in the coastal regions of Aceh, Indonesia, an area that was largely affected by the 2004 Sumatra Andaman earthquake and ensuing Indian Ocean tsunami, suggests the possibility that two closely spaced tsunamis occurred at the turn of the 14th to 15th century (Meltzner et al., 2010; Sieh et al., 2015). Here, we present evidence of two buried sand layers in the coastal marshes of West Aceh, possibly representing these penultimate predecessors of the 2004 tsunami. We discovered the sand layers in an until recently inaccessible area of a previously studied beach ridge plain about 15 km North of Meulaboh, West Aceh. Here, the 2004 tsunami left a continuous, typically a few cm thick sand sheet in the coastal hinterland in low-lying swales that accumulate organic-rich deposits and separate the sandy beach ridges. In keeping with the long-term progradation of the coastline, older deposits have to be sought after further inland. Using a hand auger, the buried sand layers were discovered in 3 cores in a flooded and highly vegetated swale in about 1 km distance to the shoreline. The pair of sand layers occurs in 70-100 cm depth and overlies 40-60 cm of dark-brown peat that rests on the basal sand of the beach ridge plain. The lower sand layer is only 1-6 cm thick, whereas the upper layer is consistently thicker, measuring 11-17 cm, with 8-14 cm of peat in between sand sheets. Both layers consist of massive, grey, medium sand and include plant fragments. They show very sharp upper and lower boundaries clearly distinguishing them from the surrounding peat and indicating an abrupt depositional event. A previously developed age model for sediments of this beach ridge plain suggest that this pair of layers could indeed correlate to a nearby buried sand sheet interpreted as tsunamigenic and deposited soon after 1290-1400AD (Monecke et al., 2008). The superb preservation at this new site allows the clear distinction of two depositional events, which, based on a first estimate of sedimentation rates, are separated by only a few decades. Future microfossil and grain size analysis as well as radiocarbon dating are necessary to assertively interpret the origin, depositional characteristics and age of the two sand layers. Meltzner et al. (2010): Coral evidence for earthquake recurrence and an A.D. 1390 - 1455 earthquake cluster at the south end of the 2004 Aceh-Andaman rupture. J. Geophys. Res. 115, B10402. Sieh et al. (2015): Penultimate predecessors of the 2004 Indian Ocean tsunami in Aceh, Sumatra: Stratigraphic, archeological and historical evidence. J. Geophys. Res. Solid Earth, 120, 308-325. Monecke et al. (2008): A 1,000-year sedimentary record of tsunami recurrence in northern Sumatra. Nature, 455, 1232-1234.

Influence of forest management on the changes of organic soil properties in border part of Kragle Mokradlo Peatland (Stolowe Mountains National Park, Poland)

NASA Astrophysics Data System (ADS)

Bogacz, A.; Roszkowicz, M.

2009-04-01

SUMMARY The aim of this work was to determine the properties of organic soils modified by man, muddy and fluvial process. Peat horizons were analyzed and classified by types - and species of peat. Three profiles of shallow peat and peaty gley soils identified. Investigation showed that organic soil developed on a sandy weathered sandstone base according to oligotrophic type of sites. Organic horizons were mixed with sand and separated by sandy layers. Those soils were classified as Sapric Histosols Dystric or Sapric Gleysols Histic (WRB 2006). The throphism of organic soil in this object resulted from both natural factors and anthropo-pedogenesis. key words: peat deposit, organic soils, soil properties, muddy process, sandy layers INTRODUCTION The areas of Stolowe Mountains National Park were influenced by forestry management. Many peatlands in the Park area were drained for forestry before World War II. Several amelioration attempts were undertaken as early as in the nineteenth century. The system of forest roads were built on drained areas. The Kragle Mokradlo Peatland is located in the Skalniak plateau. The object is cut by a melioration ditch. This ditch has been recently blocked to rewet the objects. Several forest roads pass in the close neighbourhood of investigated areas. In a border part of Kragle Mokradlo Peatlands, we can observe artificial spruce habitat. Investigated object represents shallow peat soil developed on sandy basement. The early investigations showed that peaty soils were also covered by sandstone - related deposits, several dozen centimeter thick (BOGACZ 2000). Those layers was developed from sandstone weathered material transported by wind and water. The aim of presented works was to determine the stage of evolution of organic soils on the base on their morphological, physical and chemical properties. MATERIAL AND METHODS Peat soils in different locations (3 profiles, 18 samples) were selected for examination. Peat samples were collected from study areas using a 6.0 cm diameter Instorfu peat auger (HORAWSKI 1987). Soil horizons were determined on the basis of colour, degree of organic matter decomposition and the quality of vegetation remains. Cores were taken to the depth where underlying mineral material was encountered. The cores ware sectioned to subsamples at intervals at major stratigrafic breaks. Some physical, chemical properties and botanical composition of peat were determined in this material. Differentiation in botanical composition of peat was analyzed by the microscopic method and subsequently classified according to the Polish standards (Oznaczanie gatunku...1977). Peat humification degree was measured using two methods: SPEC method and half syringe method (LYNN at all. 1974). Ash content was estimated by combusting the material in a muffle furnace at 500oC for 4 hours. The texture of mineral horizons was determined using the Bouyoucos hydrometer method (GEE AND BOUNDER 1986). The specific gravity (W) and bulk density (Z) of organic soils were calculated using the following formula's (ZAWADZKI 1970): W=0.11A+1.451, (1.451) represents the specific gravity of humus, Z =0.004A+0.0913, A is a ash content and constant (0.0913) represents the bulk density of humus. The following chemical properties of organic soil horizons were analyzed: content of total carbon and nitrogen, acidity in H2O and 1mol dm-3 KCl and CECe in CH3COONH4 at pH 7. Base saturation (BS) of soil sorption complex was calculated. The soils were classified to reference groups in WRB Classification System (WRB 2006). RESULTS AND DISSCUSION Based on the cores, -the soils in the border part of Kragle Mokradlo Peatland area were classified as Sapric Histosols Dystric or Sapric Gleysols Histic (WRB 2006). Soils represented ombrogenic type of hydrological conditions. In that site, an ombrogenic type of hydrological input is the predominant mechanism of soil evolution. Soil examined in this study have developed in oligotrophic type of site. Organic soils developed on sandy weathered sandstones. The depth of organic horizons ranged from 40 to 80 cm. The object represented spruce forests habitat introduced by man. Organic horizons were separated by sandy layers. The process of sandstone weathering and forestry management changed morphological features of soils. Presently, the area is under the influence of fluvigenic type of hydrological input, too. Geobotanical analyses of peat layers indicated significant presence of preserved fragments of roots grasses, Sphagnum sp. and Bryales sp. Hemic or sapric material were usually present in organic horizons of this object. Analysis of organic horizons showed that their specific gravity was about 1.58-2.25 g cm-3, the bulk density was 0.14-0.42 g cm-3. The total porosity was in the range 82.0-91.1% and the ash content: in the range 11.74-77.96% of soil dry matter. Organic material consisting of weathered sandstone was likely to move down the profiles, increasing the concentration of sand and silt fractions in organic horizons. The similar phenomenon of residual deposits was reported by KLEMENTOWSKI (1979). The values of bulk density of peatland soils are connected with the high ash content. Ash content was different in situated layers. This is caused by the muddy and fluvial process. This situation was influenced by trophical status of this soils. The pH of sand and peat layers in a border part of Krągłe Mokradło Peatland was strongly acidic: pH H2O 2.92-3.51, pH KCl 2.38-3.07. The acidity was lower in upper horizons than in deeper ones. The ratio C/N in organic horizons ranged between 10:1 to 40:1. Low ratios of C/N in some upper horizons were probably caused by strong mineralization of organic matter. Strongly acidic soil horizons usually exhibited high cation exchange capacity (CECe). In general, the base saturated (BS) did not exceed 50%. Organic surface horizons showed higher content of potassium, calcium and magnesium than lower horizons. CONCLUSIONS Shallow organic soils occupy the ombrotrophic sites of a border part of Kragle Mokradlo Peatland. The variety of organic soil throphism in the object resulted from the placement on the base sandstone, partial mixing of soil horizons as well as from muddy and fluvial processes. Peat horizons present in the studied profiles were generally classified as hemic and sapric, sometimes as fibric. Soil horizons exhibited differed thickness and ash content. Forest management strongly changed the properties of organic soil. REFERENCES Bogacz, A. (2000). Physical properties of organic soil in Stolowe Mountains National Park (Poland). Suo 51,3; pp.105-113. Gee, G.W. and Bauder, J.W. (1986). Particle-size analysis. In: Klute, A.(ed.) Methods of Soil Analysis Part I. Agronomy series No. 9. Am. Soc. Agronomy Soil Sci. Am, Inc., Publ., Madison, WI.pp. 383-411. Horawski, M. (1987). Torfoznawstwo dla meliorantow. Pojecia podstawowe.[Peat science for melioration. Basic definitions.]. Wydawnictwo Akademii Rolniczej w Krakowie. pp.37-39.[In Polish]. Lubliner - Mianowska, K. (1951). Wskazowki do badania torfu. Metody geobotaniczne, polowe i laboratoryjne [Hints to peat research. In: Geobotanical, field and laboratory methods] Państwowe Wydawnictwo Techniczne, Katowice.pp.58-60. [In Polish]. Lynn, W.C., Mc Kinzie, W.E., Grossman, R.B. (1974). Field Laboratory Test for characterization of Histosols. In: Histosols, their characteristics, classification and use. pp. 11-20. Oznaczanie gatunku, rodzaju i typu torfu. (1977). [Peat and peat varies. Determination of classes, sort and types of peat]. Polish standard PN-76/G-02501, [Polish Normalization Commitee]. pp.1-11.[In Polish]. Word Reference Base for Soil Resources. 1998. Word Soil Resources Report, 84. FAO-ISRIC-ISSS, Rome, pp.1-88. Zawadzki, S. (1970). Relationship between the content of organic matter and physical properties of hydrogenic soils. Polish Journal of Soil Science Vol.III, 1; pp.3-9.

The legacy of wetland drainage on the remaining peat in the Sacramento-San Joaquin Delta, California, USA

USGS Publications Warehouse

Drexler, Judith Z.; Christian S. de Fontaine,; Steven J. Deverel,

2009-01-01

Throughout the world, many extensive wetlands, such as the Sacramento-San Joaquin Delta of California (hereafter, the Delta), have been drained for agriculture, resulting in land-surface subsidence of peat soils. The purpose of this project was to study the in situ effects of wetland drainage on the remaining peat in the Delta. Peat cores were retrieved from four drained, farmed islands and four relatively undisturbed, marsh islands. Core samples were analyzed for bulk density and percent organic carbon. Macrofossils in the peat were dated using radiocarbon age determination. The peat from the farmed islands is highly distinct from marsh island peat. Bulk density of peat from the farmed islands is generally greater than that of the marsh islands at a given organic carbon content. On the farmed islands, increased bulk density, which is an indication of compaction, decreases with depth within the unoxidized peat zone, whereas, on the marsh islands, bulk density is generally constant with depth except near the surface. Approximately 55–80% of the original peat layer on the farmed islands has been lost due to landsurface subsidence. For the center regions of the farmed islands, this translates into an estimated loss of between 2900-5700 metric tons of organic carbon/hectare. Most of the intact peat just below the currently farmed soil layer is over 4000 years old. Peat loss will continue as long as the artificial water table on the farmed islands is held below the land surface.

Impact of water conditions on land surface subsidance and the decline of organic soils in Kuwasy peatland

NASA Astrophysics Data System (ADS)

Chrzanowski, S.; Szajdak, L.

2009-04-01

Organic soils as result of drainage undergo consolidation, mineralization, and subsidence of surface layer, and decline of organic matter. The rate of the subsidence of surface layer depends on a number of factors, such as ground water level, kind of peat, density of thickness of peat layer, drainage depth, climate, land use and drainage duration. These processes are connected with the changes of physical properties and lead to the conversion of organic soils into mineral-organic and mineral. The phenomena are observed in Biebrza, Notec Valley, and Kurpiowska Basin and Wieprz-Krzna channel. During last 42 years, in Kuwasy peatland from 10-13 ton per year was declined and the area of peatland decreased from 53 to 57 cm. It was observed that, peat moorsh soil of the first stadium of moorshification located on a middle decomposed peat transformed into peat-moorh soil of the second stadium of moorshification located on a high decomposed peat. However shallow peat soils were converted into mineral-moorsh and moorsh. Kuwasy peatland was meliorated twice in XX century, first one in the middle of 30 and second one in 50. It led to the farther land surface subsidence and decline of organic matter. The aim of this investigation was to evaluate the rate of land surface subsidence, decline of the area and the transformation of physic-water properties in peat-moorsh soil of different water conditions. The investigations were carried out in Kuwasy peatland, located in Biebrza Basin North-East Poland. In peat soil samples ash contents, porosity, pF curves and bulk density were determined. The analysis of these results allowed to evaluate long-term soil subsidence and to relate it to soil water conditions.

The legacy of wetland drainage on the remaining peat in the Sacramento San Joaquin Delta, California, USA

USGS Publications Warehouse

Drexler, J.Z.; De Fontaine, C. S.; Deverel, S.J.

2009-01-01

Throughout the world, many extensive wetlands, such as the Sacramento-San Joaquin Delta of California (hereafter, the Delta), have been drained for agriculture, resulting in land-surface subsidence of peat soils. The purpose of this project was to study the in situ effects of wetland drainage on the remaining peat in the Delta. Peat cores were retrieved from four drained, farmed islands and four relatively undisturbed, marsh islands. Core samples were analyzed for bulk density and percent organic carbon. Macrofossils in the peat were dated using radiocarbon age determination. The peat from the farmed islands is highly distinct from marsh island peat. Bulk density of peat from the farmed islands is generally greater than that of the marsh islands at a given organic carbon content. On the farmed islands, increased bulk density, which is an indication of compaction, decreases with depth within the unoxidized peat zone, whereas, on the marsh islands, bulk density is generally constant with depth except near the surface. Approximately 5580 of the original peat layer on the farmed islands has been lost due to land-surface subsidence. For the center regions of the farmed islands, this translates into an estimated loss of between 29005700 metric tons of organic carbon/hectare. Most of the intact peat just below the currently farmed soil layer is over 4000 years old. Peat loss will continue as long as the artificial water table on the farmed islands is held below the land surface. ?? 2009 The Society of Wetland Scientists.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikonov, V.V.

1981-01-01

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

Biochemical processes of oligotrophic peat deposits of Vasyugan Mire

NASA Astrophysics Data System (ADS)

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

2009-04-01

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 (56˚ 03´ and 56˚ 57´ NL, 82˚ 22´ and 82˚ 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

Holocene history and environmental reconstruction of a Hercynian mire and surrounding mountain landscape based on multiple proxies

NASA Astrophysics Data System (ADS)

Dudová, Lydie; Hájková, Petra; Opravilová, Věra; Hájek, Michal

2014-07-01

We discovered the first peat section covering the entire Holocene in the Hrubý Jeseník Mountains, representing an island of unique alpine vegetation whose history may display transitional features between the Hercynian and Carpathian regions. We analysed pollen, plant macrofossils (more abundant in bottom layers), testate amoebae (more abundant in upper layers), peat stratigraphy and chemistry. We found that the landscape development indeed differed from other Hercynian mountains located westward. This is represented by Pinus cembra and Larix during the Pleistocene/Holocene transition, the early expansion of spruce around 10,450 cal yr BP, and survival of Larix during the climatic optimum. The early Holocene climatic fluctuations are traced in our profile by species compositions of both the mire and surrounding forests. The mire started to develop as a calcium-rich percolation fen with some species recently considered to be postglacial relicts (Meesia triquetra, Betula nana), shifted into ombrotrophy around 7450 cal yr BP by autogenic succession and changed into a pauperised, nutrient-enriched spruce woodland due to modern forestry activities. We therefore concluded that its recent vegetation is not a product of natural processes. From a methodological viewpoint we demonstrated how using multiple biotic proxies and extensive training sets in transfer functions may overcome taphonomic problems.

Influence of a step-change increase of peat moisture content on the horizontal propagation of smouldering fires

NASA Astrophysics Data System (ADS)

Prat-Guitart, Nuria; Belcher, Claire M.; Hadden, Rory M.; Rein, Guillermo; Yearsley, Jon M.

2015-04-01

In shallow layers of peat, the transition between moss species causes a step-change of the horizontal distribution of peat moisture content. Post-fire studies in peatlands have reported shallow layers being consumed in irregular distributions. The unburned areas were found to be patches of wet Sphagnum moss. Our laboratory scale study analyses the effect of a horizontal step-change in moisture content on the spread of smouldering. We designed a laboratory-scale experiment (20×18×5 cm) within an insulated box filled with milled peat. Peat was ignited on one side of the box from which the smouldering fire horizontally self-propagates through a region of dry peat (MC1) and then through a wetter region of peat (MC2). An infrared camera, a webcam and thermocouples monitor the position of the smouldering fire spreading horizontally. The experiment was repeated with peats at different moisture content combinations to analyse the smouldering behaviour on a range of moisture content step-change conditions. The data analysis estimates the burned area and examines smouldering fire behaviour across a wide range of moisture content combinations reproducing realistic scenarios. We found that the area burned depends on peat moisture content before the step-change (MC1) as well as the increase in moisture of the step-change itself (difference between MC1 and MC2). Our study assists in researching the influence of peat moisture content on the spread of smouldering in peatland fire and contributes to a better understanding of the post-fire peatland landscape, helping to reconstruct smouldering fire events.

Age Determination of the Remaining Peat in the Sacramento-San Joaquin Delta, California, USA

USGS Publications Warehouse

Drexler, Judith Z.; de Fontaine, Christian S.; Knifong, Donna L.

2007-01-01

Introduction The Sacramento-San Joaquin Delta of California was once a 1,400 square kilometer (km2) tidal marsh, which contained a vast layer of peat ranging up to 15 meters (m) thick (Atwater and Belknap, 1980). Because of its favorable climate and highly fertile peat soils, the majority of the Delta was drained and reclaimed for agriculture during the late 1800s and early 1900s. Drainage of the peat soils changed the conditions in the surface layers of peat from anaerobic (having no free oxygen present) to aerobic (exposed to the atmosphere). This change in conditions greatly increased the decomposition rate of the peat, which consists largely of organic (plant) matter. Thus began the process of land-surface subsidence, which initially was a result of peat shrinkage and compaction, and later largely was a result of oxidation by which organic carbon in the peat essentially vaporized to carbon dioxide (Deverel and others, 1998; Ingebritsen and Ikehara, 1999). Because of subsidence, the land-surface elevation on farmed islands in the Delta has decreased from a few meters to as much as 8 m below local mean sea level (California Department of Water Resources, 1995; Steve Deverel, Hydrofocus, Inc., written commun., 2007). The USGS, in collaboration with the University of California at Davis, and Hydrofocus Inc. of Davis, California, has been studying the formation of the Delta and the impact of wetland reclamation on the peat column as part of a project called Rates and Evolution of Peat Accretion through Time (REPEAT). The purpose of this report is to provide results on the age of the remaining peat soils on four farmed islands in the Delta.

Agricultural management impact on physical and chemical functions of European peat soils.

NASA Astrophysics Data System (ADS)

Piayda, Arndt; Tiemeyer, Bärbel; Dettmann, Ullrich; Bechtold, Michel; Buschmann, Christoph

2017-04-01

Peat soils offer numerous functions from the global to the local scale: they constitute the biggest terrestrial carbon storage on the globe, form important nutrient filters for catchments and provide hydrological buffer capacities for local ecosystems. Peat soils represent a large share of soils suitable for agriculture in temperate and boreal Europe, pressurized by increasing demands for production. Cultivated peat soils, however, show extreme mineralization rates of the organic substance and turn into hotspots for green house gas emissions, are highly vulnerable to land surface subsidence, soil and water quality deterioration and thus crop failure. The aim of this study is to analyse the impact of past agricultural management on soil physical and chemical functions of peat soils in six European countries. We conducted standardized soil mapping, soil physical/chemical analysis, ground water table monitoring and farm business surveys across 7 to 10 sites in Germany, The Netherlands, Denmark, Estonia, Finland and Sweden. The results show a strong impact of past agricultural management on peat soil functions across Europe. Peat soil under intensive arable land use consistently offer lowest bearing capacities in the upper 10 cm compared to extensive and intensive grassland use, which is a major limiting factor for successful agricultural practice on peat soils. The difference can be explained by root mat stabilization solely, since soil compaction in the upper 25cm is highest under arable land use. A strong decrease of available water capacity and saturated hydraulic conductivity is consequently observed under arable land use, further intensifying hydrological problems like ponding, drought stress and reductions of hydrological buffer capacities frequently present on cultivated peat soils. Soil carbon stocks clearly decrease with increasing land use intensity, showing highest carbon stocks on extensive grassland. This is supported by the degree of decomposition, which is lowest for extensive grass land. Both findings indicate a strong impact of land use intensity and management on soil carbon losses and peat conservation on the European scale. This study provides evidence how functions of peat soils, valuable for successful agricultural production and relevant for climate change mitigation, are impacted by agricultural management.

Mapping SOC content and bulk density of a disturbed peatland relict with electromagnetic induction and DEM data

NASA Astrophysics Data System (ADS)

Altdorff, Daniel; Bechtold, Michel; van der Kruk, Jan; Tiemeyer, Bärbel; von Hebel, Christian; Huisman, Johan Alexander

2014-05-01

Peatlands represent a huge storage of soil organic carbon (SOC), and there is considerable interest to assess the total amount of carbon stored in these ecosystems. However, reliable field-scale information about peat properties, particularly SOC content and bulk density (BD) necessary to estimate C stocks, remains difficult to obtain. A potential way to acquire information on these properties and its spatial variation is the non-invasive mapping of easily recordable physical variables that correlate with peat properties, such as bulk electrical conductivity (ECa) measured with electromagnetic induction (EMI). However, ECa depends on a range of soil properties, including BD, soil and water chemistry, and water content, and thus results often show complex and site-specific relationships. Therefore, a reliable prediction of SOC and BD from ECa data is not necessarily given. In this study, we aim to explore the usefulness of Multiple Linear Regression (MLR) models to predict the peat soil properties SOC and BD from multi-offset EMI and high-resolution DEM data. The quality of the MLR models is assessed by cross-validation. We use data from a medium-scale disturbed peat relict (approximately 35ha) in Northern Germany. The potential explanatory variables considered in MLR were: EMI data of six different integral depths (approximately 0.25, 0.5, 0.6, 0.9, 1, and 1.80 m), their vertical heterogeneity, as well as several topographical variables extracted from the DEM. Ground truth information for SOC, BD content and peat layer thickness was obtained from 34 soil cores of 1 m depth. Each core was divided into several 5 to 20 cm thick layers so that integral information of the upper 0.25, 0.5, and 1 m as well as from the total peat layer was obtained. For cross-validation of results, we clustered the 34 soil cores into 4 classes using K-means clustering and selected 8 cores for validation from the clusters with a probability that depended on the size of the cluster. With the remaining 26 samples, we performed a stepwise MLR and generated separate models for each depth and soil property. Preliminary results indicate reliable model predictions for SOC and BD (R² = 0.83- 0.95). The RMSE values of the validation ranged between 3.5 and 7.2 vol. % for SOC and 0.13 and 0.37 g/cm³ for BD for the independent samples. This equates roughly the quality of SOC predictions obtained by field application of vis-NIR (visible-near infrared) presented in literature for a similar peatland setting. However, the EMI approach offers the potential to derive information from deeper depths and allows non-invasive mapping of BD variability, which is not possible with vis-NIR. Therefore, this new approach potentially provides a more useful tool for total carbon stock assessment in peatlands.

Estimating Carbon Stocks Along Depressional Wetlands Using Ground Penetrating Radar (GPR) in the Disney Wilderness Preserve (Orlando, Florida)

NASA Astrophysics Data System (ADS)

McClellan, M. D.; Comas, X.; Wright, W. J.; Mount, G. J.

2014-12-01

Peat soils store a large fraction of the global carbon (C) in soil. It is estimated that 95% of carbon in peatlands is stored in the peat soil, while less than 5% occurs in the vegetation. The majority of studies related to C stocks in peatlands have taken place in northern latitudes leaving the tropical and subtropical latitudes clearly understudied. In this study we use a combination of indirect non-invasive geophysical methods (mainly ground penetrating radar, GPR) as well as direct measurements (direct coring) to calculate total C stocks within subtropical depressional wetlands in the Disney Wilderness Preserve (DWP, Orlando, FL). A set of three-dimensional (3D) GPR surveys were used to detect variability of the peat layer thickness and the underlying peat-sand mix layer across several depressional wetlands. Direct samples collected at selected locations were used to confirm depth of each interface and to estimate C content in the laboratory. Layer thickness estimated from GPR and direct C content were used to estimate total peat volume and C content for the entire depressional wetland. Through the use of aerial photos a relationship between surface area along the depressional wetlands and total peat thickness (and thus C content) was established for the depressions surveyed and applied throughout the entire preserve. This work shows the importance of depressional wetlands as critical contributors of the C budget at the DWP.

The thin brown line: The crucial role of peat in protecting permafrost in Arctic Alaska

NASA Astrophysics Data System (ADS)

Gaglioti, B.; Mann, D. H.; Farquharson, L. M.; Baughman, C. A.; Jones, B. M.; Romanovsky, V. E.; Williams, A. P.; Andreu-Hayles, L.

2017-12-01

Ongoing warming threatens to thaw Arctic permafrost and release its stored carbon, which could trigger a permafrost-carbon feedback capable of augmenting global warming. The effects of warming air temperatures on permafrost are complicated by the fact that across much of the Arctic and Subarctic a mat of living plants and decaying litter cover the ground and buffer underlying permafrost from air temperatures. For simplicity here, we refer to this organic mat as "peat". Because this peat modifies heat flow between ground and air, the rate and magnitude of permafrost responses to changing climate - and hence the permafrost-carbon feedback - are partly slaved to the peat layer's slower dynamics. To explore this relationship, we used 14C-age offsets within lake sediments in Alaskan watersheds underlain by yedoma deposits to track the changing responses of permafrost thaw to fluctuating climate as peat accumulated over the last 14,000 years. As the peat layer built up, warming events became less effective at thawing permafrost and releasing ancient carbon. Consistent with this age-offset record, the geological record shows that early in post-glacial times when the peat cover was still thin and limited in extent, warm intervals triggered extensive thermokarst that resulted in rapid aggradation of floodplains. Today in contrast, hillslopes and floodplains remain stable despite rapid warming, probably because of the buffering effects of the extensive peat cover. Another natural experiment is provided by tundra fires like the 2007 Anaktuvuk River fire that removed the peat cover from tundra underlain by continuous permafrost and resulted in widespread thermkarsting. Further support for peat's critical role in protecting permafrost comes from the results of modeling how permafrost temperatures under different peat thicknesses respond to warming air temperature. Although post-industrial warming has not yet surpassed the buffering capacity of 14,000 years of peat buildup in Arctic Alaska, modeling suggests that a threshold is imminent.

Revegetation processes and environmental conditions in abandoned peat production fields in Estonia

NASA Astrophysics Data System (ADS)

Orru, M.; Orru, H.

2009-04-01

As a result of peat extraction, peat production has been finished in Estonia at different times in 154 peat production areas and 9,500 ha (~1% of peatlands) are abandoned, although the peat reserves are not exhausted yet; besides, several areas are not properly recultivated. In addition 12,000 ha of fens (oligotrophic peat layers) are drained and used as grasslands. If the abandoned and non-recultivated peat production areas are not vegetated, their CO2 emission is considerable and peat mineralises in such areas. The aim of the study was to find out specific ecological and geological factors, which affect recovering of peatlands and influence the recultivation. During the revision the amount and quality of the remained reserves, as well as the state of water regime, drainage network and revegetation was assessed in all 154 abandoned peat production areas. The study showed that the state of them is very variable. Some of them are covered with forest, prevailingly with birches at former drainage ditches, later supplemented by pine trees. In the others predominate grasses among plants, and various species of moss (Cladonia rei, Bryum caespiticum, Sphagnum ripariuma, Sphagnum squarrosum) occur as well. Besides, some abandoned areas are completely overgrown with cotton grass. Open abandoned peat areas, which are not covered by vegetation, are much rarer. We found out, that water regime among the factors plays most important role. Moreover abandoned peat production fields, where the environmental conditions have changed - are appropriate for growth of several moss species, which cannot inhabit the areas already occupied by other species. The most interesting discovers were: second growing site of Polia elongata in West-Estonia and Ephemerum serratum, last found in Estonia in the middle of the 19th century, was identified in central Estonia. Also Campylopus introflexus, what was unknown in Estonia. However, the changes in environmental conditions influence the peat layers structure and technical characteristics of organic soils that affect the vegetation of peatlands.

Analysis of actinides in an ombrotrophic peat core - evidence of post-depositional migration of fallout radionuclides

NASA Astrophysics Data System (ADS)

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

2013-04-01

Plutonium (239Pu, 240Pu, 241Pu, 242Pu) and uranium (236U, 238U) isotopes were analyzed in an ombrotrophic peat core from the Black Forest, Germany, representing the last 80 years of atmospheric deposition. The reliable determination of these isotopes at ultra-trace levels was possible using ultra-clean laboratory procedures and accelerator mass spectrometry. The 240Pu/239Pu isotopic ratios are constant along the core with a mean value of 0.19 ±0.02 (N = 32). This result is consistent with the acknowledged average 240Pu/239Pu isotopic ratio from global fallout in the Northern Hemisphere. The global fallout origin of Pu is confirmed by the corresponding 241Pu/239Pu (0.0012 ±0.0005) and 242Pu/239Pu (0.004 ± 0.001) isotopic ratios. The identification of the Pu isotopic composition characteristic for global fallout in peat layers pre-dating the period of atmospheric atom bomb testing (AD 1956 - AD 1980) is a clear evidence of the migration of Pu downwards the peat profile. The maximum of global fallout derived 236U is detected in correspondence to the age/depth layer of maximum stratospheric fallout (AD 1963). This finding demonstrates that the 236U bomb peak can be successfully used as an independent chronological marker complementing the 210Pb dating of peat cores. The profiles of the global fallout derived 236U and 239Pu are compared with those of 137Cs and 241Am. As typical of ombrothrophic peat, the temporal fallout pattern of 137Cs is poorly retained. Similarly like for Pu, post-depositional migration of 241Am in peat layers preceding the era of atmospheric nuclear tests is observed.

Long-Distance Translocation of Protein during Morphogenesis of the Fruiting Body in the Filamentous Fungus, Agaricus bisporus

PubMed Central

Woolston, Benjamin M.; Schlagnhaufer, Carl; Wilkinson, Jack; Larsen, Jeffrey; Shi, Zhixin; Mayer, Kimberly M.; Walters, Donald S.; Curtis, Wayne R.; Romaine, C. Peter

2011-01-01

Commercial cultivation of the mushroom fungus, Agaricus bisporus, utilizes a substrate consisting of a lower layer of compost and upper layer of peat. Typically, the two layers are seeded with individual mycelial inoculants representing a single genotype of A. bisporus. Studies aimed at examining the potential of this fungal species as a heterologous protein expression system have revealed unexpected contributions of the mycelial inoculants in the morphogenesis of the fruiting body. These contributions were elucidated using a dual-inoculant method whereby the two layers were differientially inoculated with transgenic β-glucuronidase (GUS) and wild-type (WT) lines. Surprisingly, use of a transgenic GUS line in the lower substrate and a WT line in the upper substrate yielded fruiting bodies expressing GUS activity while lacking the GUS transgene. Results of PCR and RT-PCR analyses for the GUS transgene and RNA transcript, respectively, suggested translocation of the GUS protein from the transgenic mycelium colonizing the lower layer into the fruiting body that developed exclusively from WT mycelium colonizing the upper layer. Effective translocation of the GUS protein depended on the use of a transgenic line in the lower layer in which the GUS gene was controlled by a vegetative mycelium-active promoter (laccase 2 and β-actin), rather than a fruiting body-active promoter (hydrophobin A). GUS-expressing fruiting bodies lacking the GUS gene had a bonafide WT genotype, confirmed by the absence of stably inherited GUS and hygromycin phosphotransferase selectable marker activities in their derived basidiospores and mycelial tissue cultures. Differientially inoculating the two substrate layers with individual lines carrying the GUS gene controlled by different tissue-preferred promoters resulted in up to a ∼3.5-fold increase in GUS activity over that obtained with a single inoculant. Our findings support the existence of a previously undescribed phenomenon of long-distance protein translocation in A. bisporus that has potential application in recombinant protein expression and biotechnological approaches for crop improvement. PMID:22163014

Past and Future Stability of Deep Peatland Carbon Stocks: Assessing the Nature and Fate of Carbon in a Northern Minnesota Ombrotrophic Peatland (Invited)

NASA Astrophysics Data System (ADS)

Hanson, P. J.; Chanton, J.; Iversen, C. M.; McFarlane, K. J.; Tfaily, M. M.; Xu, X.

2013-12-01

An ombrotrophic Picea-Sphagnum peatland located on the Marcell Experimental Forest in northern Minnesota is being prepared for experimental manipulations to evaluate carbon cycle responses to warming and elevated CO2. Pretreatment characterization of the peatland, which has a mean peat depth of ~3 meters, showed that belowground carbon (C) stocks were greater than 2200 MgC ha-1. This is easily 10× greater than the combined above- and belowground C stocks found in typical eastern deciduous forests. Carbon has accumulated under saturated, cool to cold conditions since the last glaciers receded some 10,000 years ago. Mean bulk-14C assessments show a modern C signature and decadal turnover time for peat in the raised hummock topography, as well as in the oxic acrotelm layer which extends to a depth of 30-cm below hollow microtopography. Deeper peat layers (below 30-cm depth) have C ages ranging from 1000- to 2000 years for relatively shallow layers, to between 7000 and 8000 years at 2.5 m depth. In contrast, the 14C signatures of dissolved inorganic C (DIC) and dissolved organic C (DOC), which reflect the substrates consumed by microbes, were relatively modern, even at depths of up to 2 meters. The modern 14C signatures indicate that microbial respiration at depth is fueled by surface inputs of DOC. Furthermore, the contrast in δ14C between solid-phase peat and DOC at deeper peat depths will allow researchers to quantify the effects of warming and elevated CO2 on the fate of peat stored in this ombrotrophic peatland for millennia. It is unclear whether C accumulation in peatlands will continue under warmer conditions associated with atmospheric and climatic change. Modeled projections for net peat C turnover throughout the peat profile will be discussed in the context of the planned warming manipulations. Initial hypotheses suggest that peat accumulation may be sustained for low levels of warming, but shift to a pattern of net carbon release as both CO2 and CH4 for warmer future climates.

Mitigating wildfire carbon loss in managed northern peatlands through restoration.

PubMed

Granath, Gustaf; Moore, Paul A; Lukenbach, Maxwell C; Waddington, James M

2016-06-27

Northern peatlands can emit large amounts of carbon and harmful smoke pollution during a wildfire. Of particular concern are drained and mined peatlands, where management practices destabilize an array of ecohydrological feedbacks, moss traits and peat properties that moderate water and carbon losses in natural peatlands. Our results demonstrate that drained and mined peatlands in Canada and northern Europe can experience catastrophic deep burns (>200 t C ha(-1) emitted) under current weather conditions. Furthermore, climate change will cause greater water losses in these peatlands and subject even deeper peat layers to wildfire combustion. However, the rewetting of drained peatlands and the restoration of mined peatlands can effectively lower the risk of these deep burns, especially if a new peat moss layer successfully establishes and raises peat moisture content. We argue that restoration efforts are a necessary measure to mitigate the risk of carbon loss in managed peatlands under climate change.

Mitigating wildfire carbon loss in managed northern peatlands through restoration

NASA Astrophysics Data System (ADS)

Granath, Gustaf; Moore, Paul A.; Lukenbach, Maxwell C.; Waddington, James M.

2016-06-01

Northern peatlands can emit large amounts of carbon and harmful smoke pollution during a wildfire. Of particular concern are drained and mined peatlands, where management practices destabilize an array of ecohydrological feedbacks, moss traits and peat properties that moderate water and carbon losses in natural peatlands. Our results demonstrate that drained and mined peatlands in Canada and northern Europe can experience catastrophic deep burns (>200 t C ha-1 emitted) under current weather conditions. Furthermore, climate change will cause greater water losses in these peatlands and subject even deeper peat layers to wildfire combustion. However, the rewetting of drained peatlands and the restoration of mined peatlands can effectively lower the risk of these deep burns, especially if a new peat moss layer successfully establishes and raises peat moisture content. We argue that restoration efforts are a necessary measure to mitigate the risk of carbon loss in managed peatlands under climate change.

Mitigating wildfire carbon loss in managed northern peatlands through restoration

PubMed Central

Granath, Gustaf; Moore, Paul A.; Lukenbach, Maxwell C.; Waddington, James M.

2016-01-01

Northern peatlands can emit large amounts of carbon and harmful smoke pollution during a wildfire. Of particular concern are drained and mined peatlands, where management practices destabilize an array of ecohydrological feedbacks, moss traits and peat properties that moderate water and carbon losses in natural peatlands. Our results demonstrate that drained and mined peatlands in Canada and northern Europe can experience catastrophic deep burns (>200 t C ha−1 emitted) under current weather conditions. Furthermore, climate change will cause greater water losses in these peatlands and subject even deeper peat layers to wildfire combustion. However, the rewetting of drained peatlands and the restoration of mined peatlands can effectively lower the risk of these deep burns, especially if a new peat moss layer successfully establishes and raises peat moisture content. We argue that restoration efforts are a necessary measure to mitigate the risk of carbon loss in managed peatlands under climate change. PMID:27346604

Pyrosequencing-based assessment of the bacteria diversity in surface and subsurface peat layers of a northern wetland, with focus on poorly studied phyla and candidate divisions.

PubMed

Serkebaeva, Yulia M; Kim, Yongkyu; Liesack, Werner; Dedysh, Svetlana N

2013-01-01

Northern peatlands play a key role in the global carbon and water budget, but the bacterial diversity in these ecosystems remains poorly described. Here, we compared the bacterial community composition in the surface (0-5 cm depth) and subsurface (45-50 cm) peat layers of an acidic (pH 4.0) Sphagnum-dominated wetland, using pyrosequencing of 16S rRNA genes. The denoised sequences (37,229 reads, average length ∼430 bp) were affiliated with 27 bacterial phyla and corresponded to 1,269 operational taxonomic units (OTUs) determined at 97% sequence identity. Abundant OTUs were affiliated with the Acidobacteria (35.5±2.4% and 39.2±1.2% of all classified sequences in surface and subsurface peat, respectively), Alphaproteobacteria (15.9±1.7% and 25.8±1.4%), Actinobacteria (9.5±2.0% and 10.7±0.5%), Verrucomicrobia (8.5±1.4% and 0.6±0.2%), Planctomycetes (5.8±0.4% and 9.7±0.6%), Deltaproteobacteria (7.1±0.4% and 4.4%±0.3%), and Gammaproteobacteria (6.6±0.4% and 2.1±0.1%). The taxonomic patterns of the abundant OTUs were uniform across all the subsamples taken from each peat layer. In contrast, the taxonomic patterns of rare OTUs were different from those of the abundant OTUs and varied greatly among subsamples, in both surface and subsurface peat. In addition to the bacterial taxa listed above, rare OTUs represented the following groups: Armatimonadetes, Bacteroidetes, Chlamydia, Chloroflexi, Cyanobacteria, Elusimicrobia, Fibrobacteres, Firmicutes, Gemmatimonadetes, Spirochaetes, AD3, WS1, WS4, WS5, WYO, OD1, OP3, BRC1, TM6, TM7, WPS-2, and FCPU426. OTU richness was notably higher in the surface layer (882 OTUs) than in the anoxic subsurface peat (483 OTUs), with only 96 OTUs common to both data sets. Most members of poorly studied phyla, such as the Acidobacteria, Verrucomicrobia, Planctomycetes and the candidate division TM6, showed a clear preference for growth in either oxic or anoxic conditions. Apparently, the bacterial communities in surface and subsurface layers of northern peatlands are highly diverse and taxonomically distinct, reflecting the different abiotic conditions in microhabitats within the peat profile.

Isotopic evidence for nitrogen mobility in peat bogs

NASA Astrophysics Data System (ADS)

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

2014-05-01

Elevated nitrogen (N) input may reduce carbon (C) storage in peat. Under low atmospheric deposition, most N is bound in the moss layer. Under high N inputs, Sphagnum is not able to prevent penetration of dissolved N to deeper peat. Nitrogen may become available to the roots of invading vascular plants. The concurrent oxygenation of deeper peat layers, along with higher supply of labile organic C, may enhance microbial decomposition and lead to peat thinning. The resulting higher emissions of greenhouse gases may accelerate global warming. Seepage of N to deeper peat has never been quantified. Here we present evidence for post-depositional mobility of atmogenic N in peat, based on natural-abundance N isotope ratios. We conducted a reciprocal peat transplant experiment between two Sphagnum-dominated peat bogs in the Czech Republic (Central Europe), differing in anthropogenic N inputs. The northern site VJ received as much as 33 kg N ha-1 yr-1 via spruce canopy throughfall. The southern site was less polluted (17.6 kg N ha-1 yr-1). Isotope signatures of living moss differed between the two sites (δ15N 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 δ15N 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.

Patterns and drivers of fungal community depth stratification in Sphagnum peat.

PubMed

Lamit, Louis J; Romanowicz, Karl J; Potvin, Lynette R; Rivers, Adam R; Singh, Kanwar; Lennon, Jay T; Tringe, Susannah G; Kane, Evan S; Lilleskov, Erik A

2017-07-01

Peatlands store an immense pool of soil carbon vulnerable to microbial oxidation due to drought and intentional draining. We used amplicon sequencing and quantitative PCR to (i) examine how fungi are influenced by depth in the peat profile, water table and plant functional group at the onset of a multiyear mesocosm experiment, and (ii) test if fungi are correlated with abiotic variables of peat and pore water. We hypothesized that each factor influenced fungi, but that depth would have the strongest effect early in the experiment. We found that (i) communities were strongly depth stratified; fungi were four times more abundant in the upper (10-20 cm) than the lower (30-40 cm) depth, and dominance shifted from ericoid mycorrhizal fungi to saprotrophs and endophytes with increasing depth; (ii) the influence of plant functional group was depth dependent, with Ericaceae structuring the community in the upper peat only; (iii) water table had minor influences; and (iv) communities strongly covaried with abiotic variables, including indices of peat and pore water carbon quality. Our results highlight the importance of vertical stratification to peatland fungi, and the depth dependency of plant functional group effects, which must be considered when elucidating the role of fungi in peatland carbon dynamics. Published by Oxford University Press on behalf of FEMS 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Effect of water-table fluctuations on the degradation of Sphagnum phenols in surficial peats

NASA Astrophysics Data System (ADS)

Abbott, Geoffrey D.; Swain, Eleanor Y.; Muhammad, Aminu B.; Allton, Kathryn; Belyea, Lisa R.; Laing, Christopher G.; Cowie, Greg L.

2013-04-01

A much improved understanding of how water-table fluctuations near the surface affect decomposition and preservation of peat-forming plant litter and surficial peats is needed in order to predict possible feedbacks between the peatland carbon cycle and the global climate system. In this study peatland plants (bryophytes and vascular plants), their litter and peat cores were collected from the Ryggmossen peatland in the boreonemoral zone of central Sweden. The extracted insoluble residues from whole plant tissues were depolymerized using thermally assisted hydrolysis and methylation (THM) in the presence of both unlabelled and 13C-labelled tetramethylammonium hydroxide (TMAH) which yielded both vascular plant- and Sphagnum-derived phenols. Methylated 4-isopropenylphenol (IUPAC: 1-methoxy-4-(prop-1-en-2-yl)benzene), methylated cis- and trans-3-(4'-hydroxyphen-1-yl)but-2-enoic acid (IUPAC: (E/Z)-methyl 3-(4-methoxyphenyl)but-2-enoate), and methylated 3-(4'-hydroxyphen-1-yl)but-3-enoic acid (IUPAC: methyl 3-(4-methoxyphenyl)but-3-enoate) (van der Heijden et al., 1997) are confirmed as TMAH thermochemolysis products of "bound" sphagnum acid and also as being specific to Sphagnum mosses. These putative biomarkers were also significant components in the unlabelled TMAH thermochemolysis products from the depolymerization of ultrasonically extracted samples from eight peat cores, one from a hummock and one from a hollow at each of the four stages along the bog plateau-to-swamp forest gradient. We have proposed and measured two parameters namely (i) σ which is defined as the total amount of these four molecules normalised to 100 mg of OC; and (ii) an index (SR%) which is the ratio of σ to the Λ parameter giving a measure of the relative amounts of "bound" sphagnum acid to the "bound" vascular plant phenols in peat moss and the surficial peat layers. Changes in σ and SR% down the bog plateau (BP), bog margin (BM) and fen lagg (FL) cores in the Ryggmossen mire indicates that the sphagnum acid bound into the peat is being degraded in the unsaturated and seasonally-saturated layers. There is then a stabilisation of Sphagnum-derived phenols in the deepest horizons of the seasonally-saturated layer and into the permanently-saturated layer. These results suggest that "bound" sphagnum acid will be stabilised in peatlands shifting to a wetter and more variable precipitation regime whereas it will be gradually stripped away (e.g. by hydrolysis/enzymatic activity) in surficial peats shifting to a drier climate, such that any subsequent rewetting of the peat could lead to anaerobic hydrolysis and fermentation of the newly exposed carbohydrates. This highlights the sensitivity of Sphagnum surficial peats to climate-induced changes in water levels albeit there may be differences in the extent of degradation along the bog-fen gradient.

Spatial variation in below ground carbon cycling in a pristine peatland, driven by present and past vegetation

NASA Astrophysics Data System (ADS)

Mathijssen, Paul; Knorr, Klaus-Holger; Gałka, Mariusz; Borken, Werner

2017-04-01

Peat carbon cycling is controlled by both large scale factors, such as climate and hydrological setting, and small scale factors, such as microtopography, vegetation, litter quality, and rooting depth. These small scale factors commonly vary within peatlands, causing variation in the carbon balance at different locations within the same site. Understanding the relationship between small scale carbon cycling and vegetation helps us to assess the variation of carbon dynamics of peatlands, because vegetation composition acts as an integrator of factors such as microtopography, hydrology, and nutrient level. Variation in vegetation illustrates spatial variation of these underlying factors. Furthermore, the presence of certain plant species affects carbon cycling directly through litter quality or aeration through root tissues. In order to understand these within-site variations in terms of carbon cycling, we investigated carbon accumulation, decomposition, and biogeochemistry of pore waters along a transect of peat cores with changing vegetation and water levels in an ombrotrophic peatland in southern Patagonia. The transect ran from a Sphagnum magellanicum dominated spot with relatively high water table, to intermediately wet spots with mixed Sphagnum/shrubs vegetation, or dominated by Cyperaceae, eventually to a more elevated and drier spot dominated by cushion plants (mainly Astelia pumila). There were large differences in peat accumulation rates and peat densities, with faster peat growth and lower densities under Sphagnum, but overall carbon accumulation rates were quite similar in the various microenvironments. At most plots C/N ratios decreased with depth, concurrent with increasing humification index derived from FT-IR spectra. But under cushion plants this relation was opposite: more humification with depth, but also C/N ratios increases. This reflected the differing source material at depth under the cushion plants, and that the cushion plant peat layers were formed on top of Sphagnum peat. The divergent source material throughout a peat core makes it difficult to use C/N ratios to indicate peat decomposition rates. Although the low peat density and higher C/N ratios indicate that overall carbon turnover is slow at Sphagnum plots, pore water methane concentrations were elevated. At cushion plant plots, however, higher redox potentials exist until greater depths due to aerenchymous roots, inhibiting methane production and release. Our results demonstrate that large variation exists within pristine bogs, in terms of decomposition patterns, organic matter quality, and carbon turnover pathways, corresponding to variation in surface moisture levels and vegetation. Furthermore, variation in carbon cycling properties are maintained in buried peat layers and reflect more the organic material of that layer, than the current surface carbon dynamics.

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

NASA Astrophysics Data System (ADS)

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

2012-04-01

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

3D modelling of mechanical peat properties in the Holocene coastal-deltaic sequence of the Netherlands

NASA Astrophysics Data System (ADS)

Koster, Kay; Stouthamer, Esther; Cohen, Kim; Stafleu, Jan; Busschers, Freek; Middelkoop, Hans

2016-04-01

Peat is abundantly present within the Holocene coastal-deltaic sequence of the Netherlands, where it is alternating with clastic fluvial, estuarine and lagoonal deposits. The areas that are rich in peat are vulnerable to land subsidence, resulting from consolidation and oxidation, due to loading by overlying deposits, infrastructure and buildings, as well as excessive artificial drainage. The physical properties of the peat are very heterogeneous, with variable clastic admixture up to 80% of its mass and rapid decrease in porosity with increasing effective stress. Mapping the spatial distribution of the peat properties is essential for identifying areas most susceptible to future land subsidence, as mineral content determines volume loss by oxidation, and porosity influences the rate of consolidation. Here we present the outline of a study focusing on mapping mechanical peat properties in relation to density and amount of admixed clastic constituents of Holocene peat layers (in 3D). In this study we use a staged approach: 1) Identifying soil mechanical properties in two large datasets that are managed by Utrecht University and the Geological Survey. 2) Determining relations between these properties and palaeogeographical development of the area by evaluating these properties against known geological concepts such as distance to clastic source (river, estuary etc.). 3) Implementing the obtained relations in GeoTOP, which is a 3D geological subsurface model of the Netherlands developed by the Geological Survey. The model will be used, among others, to assess the susceptibility of different areas to peat related land subsidence and load bearing capacity of the subsurface. So far, our analysis has focused stage 1, by establishing empirical relations between mechanical peat properties in ~70 paired (piezometer) cone penetration tests and continuously cored boreholes with LOI measurements. Results show strong correlations between net cone resistance (qn), excess pore water (u1-u0), and total vertical stress (σvo), suggesting that the overburden strongly controls the vertical differential susceptibility of peat layers to consolidation.

Comparisons of soil nitrogen mass balances for an ...

EPA Pesticide Factsheets

We compared the N budgets of an ombrotrophic bog and a minerotrophic fen to quantify the importance of denitrification in peatlands and their watersheds. We also compared the watershed upland mineral soils to bog/fen peat; lagg and transition zone peat to central bog/fen peat; and surface, mid-layer and deep soil and peat horizons. Bog and fen area were derived from a wetland boundary GIS data layer, and bog and fen volumes were calculated as the interpolated product of area and depth of peat. Atmospheric N deposition to the bog and fen were based on measurements from a station located 2km north of the bog watershed and 0.5km from the fen watershed. Precipitation was analyzed for nitrate (NO3-), ammonium (NH4+), and total N (TN), and aggregated to annual values. Outflow water samples from the bog and fen were collected as surface grab samples on each of the May-October sampling dates over the 2010-2013 study, and were analyzed and aggregated annually as for atmospheric N. Soil and peat samples were analyzed for N content, and for net ammonification (AM), nitrification (NT), and ambient (DN) and potential (DEA) denitrification rates. Nitrogen mass balances are based on mean annual atmospheric deposition and outflow; soil and peat standing stocks of N, and mean annual estimates of DN, weighted for contributions of the uplands, lagg or transition zone, and bog or fen hollows and hummocks, and accounting for soil depth effects. Annual deposition of N species was: N

Distribution and speciation of mercury in the peat bog of Xiaoxing'an Mountain, northeastern China.

PubMed

Liu, Ruhai; Wang, Qichao; Lu, Xianguo; Fang, Fengman; Wang, Yan

2003-01-01

Most reports on mercury (Hg) in boreal ecosystems are from the Nordic countries and North America. Comparatively little information is available on Hg in wetlands in China. We present here a study on Hg in the Tangwang River forested catchment of the Xiaoxing'an Mountain in the northeast of China. The average total Hg (THg) in peat profile ranged from 65.8 to 186.6 ng g(-1) dry wt with the highest at the depth of 5-10 cm. THg in the peat surface was higher than the background in Heilongjiang province, the Florida Everglades, and Birkeness in Sweden. MethylHg (MeHg) concentration ranged from 0.16 to 1.86 ng g(-1) dry wt, with the highest amount at 10-15 cm depth. MeHg content was 0.2-1.2% of THg. THg and MeHg all decreased with the depth. THg in upland layer of soil (0-20 cm) was comparable to the peat surface, but in deeper layers THg concentration in peat was much higher than that in the forested mineral soil. THg in the peat bog increased, but MeHg decreased after it was drained. THg content in plant was different; THg contents in moss (119 ng g(-1) dry wt, n=12) were much higher than in the herbage, the arbor, and the shrubs. The peat bog has mainly been contaminated by Hg deposition from the atmosphere.

Multiple sources for late-Holocene tsunamis at Discovery Bay, Washington State, USA

USGS Publications Warehouse

Williams, H.F.L.; Hutchinson, I.; Nelson, A.R.

2005-01-01

Nine muddy sand beds interrupt a 2500-yr-old sequence of peat deposits beneath a tidal marsh at the head of Discovery Bay on the south shore of the Strait of Juan de Fuca, Washington. An inferred tsunami origin for the sand beds is assessed by means of six criteria. Although all the sand beds contain marine diatoms and almost all the beds display internal stratification, the areal extent of the oldest beds is too limited to confirm their origin as tsunami deposits. The ages of four beds overlap with known late-Holocene tsunamis generated by plate-boundary earthquakes at the Cascadia subduction zone. Diatom assemblages in peat deposits bracketing these four beds do not indicate concurrent change in elevation at Discovery Bay. Diatoms in the peat bracketing a tsunami bed deposited about 1000 cal. yr BP indicate a few decimeters of submergence, suggesting deformation on a nearby upper-plate fault. Other beds may mark tsunamis caused by more distant upper-plate earthquakes or local submarine landslides triggered by earthquake shaking. Tsunamis from both subduction zone and upper-plate sources pose a significant hazard to shoreline areas in this region.

[The release of biologically active compounds from peat peloids].

PubMed

Babaskin, D V

2011-01-01

This work had the objective to study kinetics of the release of flavonoides from peat peloid compositions containing extracts of medicinal herbs in model systems.The key parameters of the process are defined. The rate of liberation of flavonoides is shown to depend on their initial concentration in the compositions being used. The influence of the flavonoide composition of the tested extracts and dimethylsulfoxide on the release of biologically active compounds contained in the starting material in the model environment is estimated. The possibility of the layer-by-layer deposition of the compositions and peat peloids in order to increase the efficacy of flavonoide release from the starting composition and to ensure more rational utilization of the extracts of medicinal plants is demonstrated.

Long-term purification efficiency of a wetland constructed to treat runoff from peat extraction.

PubMed

Karjalainen, Satu M; Heikkinen, Kaisa; Ihme, Raimo; Kløve, Bjørn

2016-01-01

Peat extraction increases the phosphorus, nitrogen, organic matter, suspended solids, and iron concentrations in runoff, resulting in negative effects on downstream water bodies. Wetlands are commonly used as natural cost-effective solutions to mitigate these negative effects. This study analyzed changes in the quality of runoff water from peat extraction areas and the long-term efficiency of constructed wetlands. The results indicate that the quality of runoff water changed after the initial drainage and during peat extraction. Nitrogen leached at high concentrations in the early stages of peat extraction following drainage, whereas the leaching of iron and phosphorus increased after peat extraction from deeper layers. Comparison of water quality and impurities retained immediately after treatment wetland construction and 14 years later showed that the treatment wetland remained functional, with good retention capacity, over a long period.

Recent Measurements of Groundwater Recharge and Discharge Through Everglades' Peat Sediments Using Short-Lived Radium Isotopes

NASA Astrophysics Data System (ADS)

Krest, J. M.; Harvey, J. W.

2002-05-01

Peat sediments are present as a nearly continuous surface layer across large areas of the Everglades. These sediments have relatively low hydraulic conductivity, impeding water exchange between surface water and the underlying surficial aquifer. Although vertical water transport does occur across the peat layer, rates are slow enough that they are difficult to quantify. Even modest rates of vertical transport, however, become significant to water budgets and nutrient cycles when they occur over a large area. In the Everglades, common methods for measuring exchange across the peat layer are prone to complications: small hydraulic gradients are difficult to measure; seepage meters tend to be imprecise at slow rates; radon profiles or emanation rates are complicated by methane bubble ebullition; chloride profiles often exhibit a strong gradient only at the surface of the peat. We are employing a method that takes advantage of the different production rates of short-lived radium isotopes (Ra-223 and Ra-224) in the peat sediments and in the underlying sand or carbonate aquifer. Pore water radium concentrations are balanced by radioactive decay and production in the surrounding sediments. As the pore water is carried across the sediment interface a temporary excess or deficit of dissolved radium exists until decay is again balanced by the new production rate. We have derived steady-state, one-dimensional models to determine flow rates on the basis of this disequilibrium. This method has the advantage of being most sensitive at the base of the peat, away from transient perturbations occurring at the surface. In addition, Ra-223 and Ra-224 are collected simultaneously, providing two independent measurements. At present we have tested the method in Water Conservation Area-1 and WCA-2A, quantifying recharge and discharge on opposite sides of Levee 39, and also in more central sites in WCA-2A. Additional work is underway in Taylor Slough and Shark Slough.

Profile distribution of polycyclic aromatic hydrocarbons in soils of drained peatlands after wildfires (Moscow region, Russia)

NASA Astrophysics Data System (ADS)

Tsibart, Anna; Gennadiev, Alexander; Koshovskii, Timur; Kovach, Roman

2014-05-01

Polycyclic aromatic compounds (PAHs) are formed in different natural and anthropogenic processes and could be found in many landscape components. These compounds are carcinogenic and belong to the group of persistent organic pollutants. The anthropogenic sources of PAHs are well-studied, but insufficient data are available on the hightemperature production of PAHs in natural processes. For example, natural fires are frequently related to the PAHs sources in landscapes, but very little factual data are on this topic. The soils of drained peatlands affected by catastrophic wildfires of 2010 and 2002 were studied in the Eastern part of Moscow Region (Russia). A total of 14 profiles of histosols and histic podsols were investigated. These series included soils of plots subjected to fires of different intensities and age, as well as soils of the background plots. Soil samples were taken from genetic horizons and from every 10 cm. The samples were analyzed for the contents of 14 prevailing individual compounds: fluorene, naphthalene, phenanthrene, chrysene, pyrene, anthracene, tetraphene, benz[a]pyrene, benzo[ghi]perylene, benzo[e]pyrene, coronene, dibenztiophene, triphenilene, benz(k)fluorantene. Morfological properties of soils after wildfires on drained peatlands were changed dramatically, the horizons of ash and char instead of organic layers were formed. These new horizons differ in the capability of PAHs accumulation. The char horizons have the highest concentrations of PAHs - up to 300 ng/g because of incomplete burning of organic matter in this sites, and the ash horizons, where the complete burning occured, contain only 10 ng/g PAHs. The highest concentrations of PAHs in soil profiles were detected after recent fires, and in cases of thick peat layers. After the combustion of peat chrysene, benz[a]pyrene, benz[e]pyrene, benzo[ghi]perylene, benz(k)fluorantene and tetraphene accumulated in soils. This is mainly the group of 4-6-nuclear compounds. The formation of high-molecular weight compounds is possible during smoldering process under a low oxygen supply. The oxygen deficit acts as a factor of the organic fragments recombination and PAHs production; therefore, relatively large amounts of PAHs are formed in peat fires. Moreover the peat fires occur directly in the soil layer; therefore, larger amounts of the resulting PAHs remain in the soils of the fire sites. The migration of low-molecular weight compounds occures in histic podsols, in histosols PAHs accumalate only in upper organic horizons. The research was conducted with the support of Russian Geographical Society.

Hydrogeological and geophysical investigations to evaluate groundwater influences on GHG emissions at the national research site Skogaryd

NASA Astrophysics Data System (ADS)

Banzhaf, Stefan; Klemedtsson, Leif; Sturkell, Erik; Nyström, Elin; Barthel, Roland

2015-04-01

The overall objective of the presented study is to explore the impact of groundwater fluctuations on greenhouse gas (GHG) emissions from peatlands and in particular from drained organic soils. The hypothesis is that drained organic soils react sensitively to changing water content, i.e. that frequent changes of groundwater level enhance the emissions of GHG from these soils and thus contribute significantly to global warming. The area under investigation is based at the Skogaryd Research Catchment (within Swedish Infrastructure for Ecosystem Sciences, SITES) in western Sweden (Meyer, et al., 2013), which was recently assigned the status of a national research site by the Swedish research council (www.vr.se). Skogaryd is a unique place in Sweden for doing research on organic soils as the area was simultaneously afforested in the 1960s and the drained fertile soils have a different land-use history. The ditching for drainage purposes throughout the entire area has had and still has a huge influence on groundwater level, which in turn is assumed to trigger GHG emissions from the organic soils at Skogaryd. To address the influence of groundwater dynamics on GHG emissions in this system, a characterisation of the subsurface using electrical resistivity and Ground Penetrating Radar (GPR) measurements was carried out. These geophysical measurements were combined with drilling along them to allow for ground truthing. An average peat thickness of around 3 m was estimated for the field site. Below the peat follows a fine sand layer, which reaches a maximum thickness of around 1.0 m right at the valley borders and thins out significantly towards the middle of the valley. Below the fine sand layer follows a layer of marine clay, which extends down to the bedrock at depths between 12 and 15 m below ground surface. The results show that the peat layer in Skogaryd forms an isolated hydraulic system without interaction with deeper or regional groundwater systems. The continuously extending clay layer hinders water moving downward or upward crossing the border of peat and clay. The peat layer is a fast reacting hydraulic system that shows immediate reaction to precipitation or drought and is independent from regional groundwater levels. The study of groundwater controls on the GHG from the drained organic soils at Skogaryd can thus focus on the fast reacting peat layer. Future investigations will show if this conclusion can be generalized for similar situations in Sweden. Geophysical measurements have proved to be a valuable method for estimating the peat thickness over a large area. Meyer A, Tarvainen L, Nousratpour A, Björk RG, Ernfors M, Grelle A, Kasimir Klemedtsson Å, Lindroth A, Räntfors M, Rütting T, Wallin G, Weslien P, Klemedtsson L (2013) A fertile peatland forest does not constitute a major greenhouse gas sink. Biogeosciences 10: 7739-7758 DOI 10.5194/bg-10-7739-2013

Soil organic matter mineralization of permafrost peat lands and sensitivity to temperature and lack of oxygen

NASA Astrophysics Data System (ADS)

Lamprecht, Richard E.; Diáková, Kateřina; Voigt, Carolina; Šantrůčková, Hana; Martikainen, Pertti; Biasi, Christina

2017-04-01

Globally, a significant pool of soil organic carbon (SOC) (Tarnocai et al. 2009) is stored in arctic peatlands where extensive permafrost prevents the decomposition of old soil organic matter (SOM). Vulnerability of ancient organic depositions in changing environment becomes a considerable issue in future climate models. Palsa mires, a typical cryogenic peatland type in subarctic tundra, are not only an important SOC pool but also have been reported as a source of nitrous oxide (N2O) (Marushchak et al. 2011). Microbial SOM mineralization and its sensitivity to changing environmental conditions are crucial to understand future C losses and greenhouse gas (GHG) fluxes in this abundant landform of subarctic region. The purpose of this experiment was to determine potential SOM mineralization in different layers of deep soil cores from an Arctic peatland. First, we aimed to define a response of C losses and GHG exchange rates to temperature and aerobic/anaerobic conditions in different peat layers down to the permafrost and beyond. Secondly, we sought for relations among SOM mineralization, nutrient availability and parameters of indigenous microbial community. Finally, we attempted to link the potential SOM mineralization of the different peat layers with surface GHG fluxes from a proceeding study conducted with the same, intact soil cores. Five deep peat soil cores were separated into five layers (0 20, 20 40, 40 60 cm, permafrost interface and permafrost layer). Homogenized peat was incubated in a factorial set-up of three temperatures (4, 10, and 16 °C) under aerobic and anaerobic conditions. At the beginning and the end of the total 5.5-months incubation period, we determined C and N availability, microbial biomass and potential activities of extracellular enzymes. Heterotrophic respiration (CO2), methane (CH4) and nitrous oxide (N2O) emissions were monitored weekly at the initial phase and biweekly later during the incubation. First results show that C-loss from aerobic decomposition dominated over C-loss from anaerobic decomposition with clear temperature sensitivities in different peat layers. Moreover, the peat layers showed definite patterns especially to N2O losses, less for CO2 losses. This study addresses the essential question to which extent deeper soil horizons of subarctic organic depositions contribute to the total soil GHG fluxes, and whether the nutrient availability, microbial community and environmental factors (i.e. temperature, O2 availability) constrain the SOM mineralization. REFERENCES Marushchak ME, Pitkämäki A, Koponen H, Biasi C, Seppälä M, Martikainen PJ (2011) Hot spots for nitrous oxide emissions found in different types of permafrost peatlands. Global Change Biol 17:2601-2614 Tarnocai C, Canadell JG, Schuur EAG, Kuhry P, Mazhitova G, Zimov S (2009) Soil organic carbon pools in the northern circumpolar permafrost region. Global Biogeochem Cycles 23

Mobile geophysical study of peat deposits in Fuhrberger Field, Germany

NASA Astrophysics Data System (ADS)

Wunderlich, T.; Petersen, H.; Hagrey, S. A. al; Rabbel, W.

2012-04-01

In the water protection area of Fuhrberger Field, north of Hanover, geophysical techniques were applied to study the stakeholder problem of the source detection for nitrate accumulations in the ground water. We used our mobile multisensor platform to conduct measurements using Ground Penetrating Radar (GPR, 200 MHz antenna) and Electromagnetic Induction (EMI, EM31). This aims to study the subsurface occurrences of peat deposits (surplus of organic carbon) supposed to be a source of nitrate emissions due to the aeration and the drawdown of groundwater levels (e.g. by pumping, drainage etc.). Resulting EMI and GPR signals show high data quality. Measured apparent electrical conductivity shows very low values (<10 mS/m) due to the mainly sandy subsurface. For this medium, both methods are expected to penetrate down to 3-5 m depth. GPR radargrams, time slices of GPR reflection energy and EMI apparent electrical conductivities are plotted on aerial photographs and compared to each other's and with vegetation intensity. We could separate areas characterized by low reflection energy and high conductivity, and vice versa. Briefly, organic rich sediments such as peats are assumed to have a relative high conductivity and thus low GPR reflectivity. Some areas of local conductivity increase correspond to a deep reflection interface (as seen in the radargrams), which even vanishes due to the high attenuation caused by the high conductivity. This implies that the upper layer is more conductive than the lower layer. Several local areas with these characteristics are found at the study sites. We recommend shallow drillings at representative points to deliver the necessary confirmation with ground truth information. Acknowledgments: iSOIL (Interactions between soil related sciences - Linking geophysics, soil science and digital soil mapping) is a Collaborative Project (Grant Agreement number 211386) co-funded by the Research DG of the European Commission within the RTD activities of the FP7 Thematic Priority Environment.

Historical Tsunami Records on Russian Island, the Sea of Japan

NASA Astrophysics Data System (ADS)

Razjigaeva, N. G.; Ganzey, L. A.; Grebennikova, T. A.; Arslanov, Kh. A.; Ivanova, E. D.; Ganzey, K. S.; Kharlamov, A. A.

2018-04-01

In this article, we provide data evidencing tsunamis on Russian Island over the last 700 years. Reconstructions are developed based on the analyses of peat bog sections on the coast of Spokoynaya Bay, including layers of tsunami sands. Ancient beach sands under peat were deposited during the final phase of transgression of the Medieval Warm Period. We used data on diatoms and benthic foraminifers to identify the marine origin of the sands. The grain size compositions of the tsunami deposits were used to determine the sources of material carried by the tsunamis. The chronology of historical tsunamis was determined based on the radiocarbon dating of the underlying organic deposits. There was a stated difference between the deposition environments during tsunamis and large storms during the Goni (2015) and Lionrock (2016) typhoons. Tsunami deposits from 1983 and 1993 were found in the upper part of the sections. The inundation of the 1993 tsunami did not exceed 20 m or a height of 0.5 m a.m.s.l. (0.3 above high tide). The more intensive tsunami of 1983 had a run-up of 0.65 m a.m.s.l. and penetrated inland from the shoreline up to 40 m. Sand layer of tsunami 1940 extend in land up to 50 m from the present shoreline. Evidence of six tsunamis was elicited from the peat bog sections, the deposits of which are located 60 m from the modern coastal line. The deposits of strong historic tsunamis in the Japan Sea region in 1833, 1741, 1614 (or 1644), 1448, the XIV-XV century and 1341 were also identified on Russian Island. Their run-ups and inundation distances were also determined. The strong historic tsunamis appeared to be more intensive than those of the XX century, and considering the sea level drop during the Little Ice Age, the inundation distances were as large as 250 m.

Historical Tsunami Records on Russian Island, the Sea of Japan

NASA Astrophysics Data System (ADS)

Razjigaeva, N. G.; Ganzey, L. A.; Grebennikova, T. A.; Arslanov, Kh. A.; Ivanova, E. D.; Ganzey, K. S.; Kharlamov, A. A.

2018-03-01

In this article, we provide data evidencing tsunamis on Russian Island over the last 700 years. Reconstructions are developed based on the analyses of peat bog sections on the coast of Spokoynaya Bay, including layers of tsunami sands. Ancient beach sands under peat were deposited during the final phase of transgression of the Medieval Warm Period. We used data on diatoms and benthic foraminifers to identify the marine origin of the sands. The grain size compositions of the tsunami deposits were used to determine the sources of material carried by the tsunamis. The chronology of historical tsunamis was determined based on the radiocarbon dating of the underlying organic deposits. There was a stated difference between the deposition environments during tsunamis and large storms during the Goni (2015) and Lionrock (2016) typhoons. Tsunami deposits from 1983 and 1993 were found in the upper part of the sections. The inundation of the 1993 tsunami did not exceed 20 m or a height of 0.5 m a.m.s.l. (0.3 above high tide). The more intensive tsunami of 1983 had a run-up of 0.65 m a.m.s.l. and penetrated inland from the shoreline up to 40 m. Sand layer of tsunami 1940 extend in land up to 50 m from the present shoreline. Evidence of six tsunamis was elicited from the peat bog sections, the deposits of which are located 60 m from the modern coastal line. The deposits of strong historic tsunamis in the Japan Sea region in 1833, 1741, 1614 (or 1644), 1448, the XIV-XV century and 1341 were also identified on Russian Island. Their run-ups and inundation distances were also determined. The strong historic tsunamis appeared to be more intensive than those of the XX century, and considering the sea level drop during the Little Ice Age, the inundation distances were as large as 250 m.

Predicting drought propagation within peat layers using a three dimensionally explicit voxel based model

NASA Astrophysics Data System (ADS)

Condro, A. A.; Pawitan, H.; Risdiyanto, I.

2018-05-01

Peatlands are very vulnerable to widespread fires during dry seasons, due to availability of aboveground fuel biomass on the surface and belowground fuel biomass on the sub-surface. Hence, understanding drought propagation occurring within peat layers is crucial with regards to disaster mitigation activities on peatlands. Using a three dimensionally explicit voxel-based model of peatland hydrology, this study predicted drought propagation time lags into sub-surface peat layers after drought events occurrence on the surface of about 1 month during La-Nina and 2.5 months during El-Nino. The study was carried out on a high-conservation-value area of oil palm plantation in West Kalimantan. Validity of the model was evaluated and its applicability for disaster mitigation was discussed. The animations of simulated voxels are available at: goo.gl/HDRMYN (El-Nino 2015 episode) and goo.gl/g1sXPl (La-Nina 2016 episode). The model is available at: goo.gl/RiuMQz.

A geospatial model to quantify mean thickness of peat in cranberry bogs

USDA-ARS?s Scientific Manuscript database

Commercial cranberry (Vaccinium macrocarpon Ait.) is cultivated on peatlands, which consist of sedimentary deposits of peat capped by a 0.3-1 m of artificial sand. Despite distinct soil layering, a general paucity of information exists on the physical properties of cranberry bogs. Field measurements...

A geospatial model to quantify mean thickness of peat in cranberry bogs

USDA-ARS?s Scientific Manuscript database

Commercial cranberry (Vaccinium macrocarpon Ait.) is cultivated on peatlands, which consist of sedimentary deposits of peat capped by a 0.3-1 m of artificial sand. Despite distinct soil layering, a general paucity of information exists on the physical properties of cranberry bogs. Field measurement...

137Cs in the fungal compartment of Swedish forest soils.

PubMed

Vinichuk, Mykhaylo M; Johanson, Karl J; Taylor, Andy F S

2004-05-05

The (137)Cs activities in soil profiles and in the mycelia of four ectomycorrhizal fungi were studied in a Swedish forest in an attempt to understand the mechanisms governing the transfer and retention of (137)Cs in forest soil. The biomass of four species of fungi was determined and estimated to be 16 g m(-2) in a peat soil and 47-189 g m(-2) in non-peat soil to the depth of 10 cm. The vertical distribution was rather homogeneous for two species (Tylospora spp. and Piloderma fallax) and very superficial for Hydnellum peckii. Most of the (137)Cs activity in mycelium of non-peat soils was found in the upper 5 cm. Transfer factors were quite high even for those species producing resupinate sporocarps. In the peat soil only approximately 0.3% of the total (137)Cs inventory in soil was found in the fungal mycelium. The corresponding values for non-peat soil were 1.3, 1.8 and 1.9%.

Soils of peatlands: histosols and gelisols

Treesearch

Randy Kolka; Scott D. Bridgham; Chien-Lu Ping

2016-01-01

Peatlands are a subset of wetlands that have accumulated significant amounts of soil organic matter. Soils of peatlands are colloquially known as peat, with mucks referring to peats that are decomposed to the point that the original plant remains are altered beyond recognition (Chapter 6, SSSA 2008). Generally, soils with a surface organic layer >40 cm thick...

Flow path oscillations in transient ground-water simulations of large peatland systems

USGS Publications Warehouse

Reeve, A.S.; Evensen, R.; Glaser, P.H.; Siegel, D.I.; Rosenberry, D.

2006-01-01

Transient numerical simulations of the Glacial Lake Agassiz Peatland near the Red Lakes in Northern Minnesota were constructed to evaluate observed reversals in vertical ground-water flow. Seasonal weather changes were introduced to a ground-water flow model by varying evapotranspiration and recharge over time. Vertical hydraulic reversals, driven by changes in recharge and evapotranspiration were produced in the simulated peat layer. These simulations indicate that the high specific storage associated with the peat is an important control on hydraulic reversals. Seasonally driven vertical flow is on the order of centimeters in the deep peat, suggesting that seasonal vertical advective fluxes are not significant and that ground-water flow into the deep peat likely occurs on decadal or longer time scales. Particles tracked within the ground-water flow model oscillate over time, suggesting that seasonal flow reversals will enhance vertical mixing in the peat column. The amplitude of flow path oscillations increased with increasing peat storativity, with amplitudes of about 5 cm occurring when peat specific storativity was set to about 0.05 m-1. ?? 2005 Elsevier B.V. All rights reserved.

Influence of different kind of peats on some physic-chemical properties, biochemical activity, the content of different forms of nitrogen and fractions of humic substances of The Great Vasyugan Mire

NASA Astrophysics Data System (ADS)

Inisheva, L. I.; Szajdak, L.

2009-04-01

Mires, or peatlands belong to the wetlands ecosystems where carbon is bounded in primary production and deposited as peat in water saturated, anoxic conditions. In those conditions, the rate of the supply of new organic matter has exceeded that the decomposition, resulting in carbon accumulation. Place of sampling belongs to an oligotrophic landscapes of the river Klyuch basin in spurs of Vasyugan mire. The catchment represents reference system for Bokchar swampy area (political district of Tomsk region). Landscape profile crosses main kinds of swampy biogeocoenosis (BGC) toward the mire center: paludal tall mixed forest, pine undershrub Sphagnum (high riam, trans-accumulative part of a profile, P2), pine-undershrub Sphagnum (low riam, transit part, P3), sedge-moss swamp (eluvial part, P5). The latter represents an eluvial part of a slope of watershed massif where it is accomplished discharge of excess, surface, soil-mire waters. The depth of peat deposit of sedge-moss swamp reaches 2,5m. To the depth of 0,6m there is a layer of Sphagnum raised bog peat, then it is a mesotrophic Scheuchzeria Sphagnum layer and at the bottom there is a thick layer of low-mire horsetail peat. The samples of peats were taken from two places (P2 and P3), both from the depth 0-75 cm of the great Vasyugan Mire. These materials represent (P2) Sphagnum fuscum peat (ash content ranged from 10.8 to 15.1%), but samples P3 belong to low-moor sedge peat (ash content ranged from 4.5-4.8%). The differences in water level, redox potential, pH, degree of degradation, bulk density, number of microorganisms, activity of enzymes, different kinds of nitrogen and humic substances were studied in two different peat soils characterized by different type of peat. In general in P2 the redox potential changed from 858 to /-140/ mV, higher activity of xanthine oxidase and peroxidase, different kinds of microorganisms (ammonifing bacteria and cellulose decomposing microorganisms) and different kinds of nitrogen (mineral, easily hydrolysable, hardly hydrolysable and non-hydrolyzable), bitumines, 3 fractions of humic acids and 3 fractions of fulvic acids were determined in the deep 0-25 cm than in 50-75 cm. The ratio HA/FA in the depth 0-25 cm was equal to from 1.87, but in the depth 50-75 cm was equal to 7.66. Contrary was observed for P3. For this peat with the increase of the deep of sampling the decrease of total nitrogen, activity of enzymes (xanthine oxidase and peroxidase) is connected with the changes of Fe+2/Fe+3 and lower difference of redox potential than in P2. The ratio HA/FA in the depth 0-25 cm was equal to 0.56, but in the depth 50-70 cm was equal to 0.84.

Biologically Active Organic Matter in Soils of European Russia

NASA Astrophysics Data System (ADS)

Semenov, V. M.; Kogut, B. M.; Zinyakova, N. B.; Masyutenko, N. P.; Malyukova, L. S.; Lebedeva, T. N.; Tulina, A. S.

2018-04-01

Experimental and literature data on the contents and stocks of active organic matter in 200 soil samples from the forest-tundra, southern-taiga, deciduous-forest, forest-steppe, dry-steppe, semidesert, and subtropical zones have been generalized. Natural lands, agrocenoses, treatments of long-term field experiments (bare fallow, unfertilized and fertilized crop rotations, perennial plantations), and different layers of soil profile are presented. Sphagnum peat and humus-peat soil in the tundra and forest-tundra zones are characterized by a very high content of active organic matter (300-600 mg C/100 g). Among the zonal soils, the content of active organic matter increases from the medium (75-150 mg C/100 g) to the high (150-300 mg C/100 g) level when going from soddy-podzolic soil to gray forest and dark-gray forest soils and then to leached chernozem. In the series from typical chernozem to ordinary and southern chernozem and chestnut and brown semidesert soils, a decrease in the content of active organic matter to the low (35-75 mg C/100 g) and very low (<35 mg C/100 g) levels is observed. Acid brown forest soil in the subtropical zone is characterized by a medium supply with active organic matter. Most arable soils are mainly characterized by low or very low contents of active organic matter. In the upper layers of soils, active organic matter makes up 1.2-11.1% of total Corg. The profile distribution of active organic matter in the studied soils coincides with that of Corg: their contents appreciably decrease with depth, except for brown semidesert soil. The stocks of active organic matter vary from 0.4 to 5.4 t/ha in the layer of 0-20 cm and from 1.0 to 12.4/ha in the layer of 0-50 cm of different soil types.

Development of a multidisciplinary method for mapping spatial extent and C-content of tropical ombrotrophic peatlands

NASA Astrophysics Data System (ADS)

Illés, Gábor; Kristijono, Agus; Pfeifer, Norbert; Pásztor, László; Shandhyavitri, Ari; Szatmári, Gábor; Sutikno, Sigit; Molnár, Gábor; László, Péter; Árvai, Mátyás; Mészáros, János; Koós, Sándor; Bakacsi, Zsófia; Takács, Katalin; Király, Géza; Székely, Balázs

2017-04-01

One of the world's most worrying environmental problems is the peat land CO2 emission problem of Indonesia: peat lands developed during the Quaternary are now under strong human influence; the artificial lowering of the natural water table leads to rapid drying and compaction of the peat layer, which then becomes vulnerable to subsurface fire. The emitted CO2 of this process is assessed to be 0.5 billion tonnes from Indonesia that is slightly higher than total emission of e.g. United Kingdom in 2014 (0.42 billion tonnes). To cope with the problem it is inevitable to assess the extents of peat lands and volumetric estimation of the potentially affected layers. Methods suitable for mapping of the peat lands (current situation and as far as possible retrospectively), thickness determination and partly thickness estimation of the peat layer are integrated in an advanced geostatistical approach building upon geomorphic, ecological, remote sensing, and geophysical methods to provide information on peat matrix attributes such as peat thickness of organo-mineral horizons between peat and underlying substrate, the presence of buried wood, buttressed trees or tip-up pools and soil type. In order to cope with the problem, our research group is developing a multidisciplinary methodology making use of our experience in soil science, GIS, remote sensing for forestry and ecology, geomorphometry, geophysics, LiDAR remote sensing, parameter estimation and geostatistical methods. The methodology is based largely on GIS data integration, but also applies technologies of 'big data' processing. Our integrative attitude ensures the holistic consideration of the problem, analyzing its origins, temporal development and varying spatial extent, its subprocesses in a multi-scale, inter- and transdisciplinary approach. At the same time practical problems, feasibility, costs, and human resource need consideration in order to design a viable solution. In the development of the solution, elements of gathered experience is integrated acquired in previous similar projects in Hungary, in the Pannonian Basin and in Indonesia, in southern Kalimantan and Indragiri Hilir, Sumatra. The pointwise and profilewise data acquisition of peat forms is converted to mapping methods augmented with a sophisticated sampling strategy. Besides the similarities - freshwater, ombrotrophic peatlands - we also have to focus on remarkable dissimilarities - e.g., herbaceous vs. woody peat material. In the case of the Pannonian Basin the peat occurrences have been developed as the filling up of the floodplains. In the Indonesian case, however, only the basin flanks are partly comparable to that generation mechanism, whereas see level changes play an important role in the development of the vast Indonesian peat occurrences. Geomorphometric approach helps in designing the sample strategy, remote sensing tools are responsible to deliver high-resolution topographic data as input. The varying thickness is assessed with geophysical measurements and shallow boreholes deployed at sampling points and profiles dictated by the sophisticated sampling strategy. During the measurement and sampling the experience gathered is fed back to the sampling strategy giving a dynamic plan for the continuation of the sampling. The advanced evaluation and visualization techniques applied result in a digital map system that also contains estimates on its quality and accuracy in the spatial context. This new approach brings us closer to the understanding of Indonesian peatland development that may also be used elsewhere in similar environmental contexts.

Seasonal changes in peatland surface elevation recorded at GPS stations in the Red Lake Peatlands, northern Minnesota, USA

USGS Publications Warehouse

Reeve, A.S.; Glaser, P.H.; Rosenberry, Donald O.

2013-01-01

Northern peatlands appear to hold large volumes of free-phase gas (e.g., CH4 and CO2), which has been detected by surface deformations, pore pressure profiles, and electromagnetic surveys. Determining the gas content and its impact in peat is challenging because gas storage depends on both the elastic properties of the peat matrix and the buoyant forces exerted by pore fluids. We therefore used a viscoelastic deformation model to estimate these variables by adjusting model runs to reproduce observed changes in peat surface elevation within a 1300 km2 peatland. A local GPS network documented significant changes in surface elevations throughout the year with the greatest vertical displacements associated with rapid changes in peat water content and unloadings due to melting of the winter snowpack. These changes were coherent with changes in water table elevation and also abnormal pore pressure changes measured by nests of instrumented piezometers. The deformation model reproduced these changes when the gas content was adjusted to 10% of peat volume, and Young's modulus was varied between 5 and 100 kPa as the peat profile shifted from tension to compression. In contrast, the model predicted little peat deformation when the gas content was 3% or lower. These model simulations are consistent with previous estimates of gas volume in northern peatlands and suggest an upper limit of gas storage controlled by the elastic moduli of the peat fabric.

The change of soil properties after wildfires in drained peatlands (Moscow region, Russia)

NASA Astrophysics Data System (ADS)

Koshovskii, Timur; Tsibart, Anna; Smirnova, Maria; Valentina, Gavrilova; Anna, Kiseleva

2014-05-01

The peat fires differ from the forest and grassland fires, because the soil organic matter acts as burning material. The deep peat horizons are heated or burned during smoldering fires, causing the dramatic change in soil properties. But the most of available data are devoted to changes in organo-mineral soils. In addition, the alteration in hydrological regime, for instance drainage, makes landscapes and soils very vulnerable to wildfires. Drained peatlands are widespread in the European part of Russia and they are affected to extreme wildfires of 2010. So there is a need of post-fire peat soils investigations in this region. During current research the soils of drained peatlands of Moscow Region (Russia) subjected to wildfires of 2002 and 2010 were studied. A total of 14 profiles including background and post-pyrogenic histosols and histic podsols were investigated. Soil samples were taken from genetic horizons and from every 10 cm in cases of thick horizons. The morfological properties of soil profiles were studied and the samples were analysed on macroelements content and organic carbon. The total organic carbon contentrations were detected with spectrofotometric method and the concentrations of macroelements were analysed with X-ray fluorescence method. After wildfires on drained peatlands morfological and physico-chemical properties of soils were changed, the horizons of ash (up to 5 cm) and char (up to 3 cm) instead of organic layers were formed. In addition, the plots of post-pirogenic landscape were characterized by high variability of soil properties. For instance, the thickness of organic layer changed from 5 to 30 cm in a small plot of 5X5 m. The changes in element composition were detected. The peat horizons of background histosols had 80-90% of SiO2, 9-5,8% of Al2O3,1,5-5,6% of Fe2O3, 3,7-6,3% of CaO, 0,7-2,8 % of MnO. Background histic podsols contained 88-90% of SiO2, to 4,8% of Al2O3, and the proportion of Fe2O3 and MnO was about 2,3%. After the fire ash horizons had elevated concentrations of Al2O3 (9-17%), Fe2O3 (4-11%), P2O3 (1-1,8 %), CaO (1,9-2,8 %) and K2O (0,1-1,9%). The char horizons had composition similar to background peat. On the one hand the loss of organic matter took place after burning. But on the other hand after the fire new stage of humus formation started and in 2 years after the burning the content of organic carbon reached up to 10 % in upper horizons.

Effects of spatial heterogeneity in moisture content on the horizontal spread of peat fires.

PubMed

Prat-Guitart, Nuria; Rein, Guillermo; Hadden, Rory M; Belcher, Claire M; Yearsley, Jon M

2016-12-01

The gravimetric moisture content of peat is the main factor limiting the ignition and spread propagation of smouldering fires. Our aim is to use controlled laboratory experiments to better understand how the spread of smouldering fires is influenced in natural landscape conditions where the moisture content of the top peat layer is not homogeneous. In this paper, we study for the first time the spread of peat fires across a spatial matrix of two moisture contents (dry/wet) in the laboratory. The experiments were undertaken using an open-top insulated box (22×18×6cm) filled with milled peat. The peat was ignited at one side of the box initiating smouldering and horizontal spread. Measurements of the peak temperature inside the peat, fire duration and longwave thermal radiation from the burning samples revealed important local changes of the smouldering behaviour in response to sharp gradients in moisture content. Both, peak temperatures and radiation in wetter peat (after the moisture gradient) were sensitive to the drier moisture condition (preceding the moisture gradient). Drier peat conditions before the moisture gradient led to higher temperatures and higher radiation flux from the fire during the first 6cm of horizontal spread into a wet peat patch. The total spread distance into a wet peat patch was affected by the moisture content gradient. We predicted that in most peat moisture gradients of relevance to natural ecosystems the fire self-extinguishes within the first 10cm of horizontal spread into a wet peat patch. Spread distances of more than 10cm are limited to wet peat patches below 160% moisture content (mass of water per mass of dry peat). We found that spatial gradients of moisture content have important local effects on the horizontal spread and should be considered in field and modelling studies. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Relationships among macerals, minerals, miospores and paleoecology in a column of Redstone coal (Upper Pennsylvanian) from north-central West Virginia (U.S.A.)

USGS Publications Warehouse

Grady, W.C.; Eble, C.F.

1990-01-01

Two distinct paleoenvironments are represented in vertical succession in a column of Redstone coal in north-central West Virginia as indicated by a study of 37 consecutive 3-cm (0.1 ft) increments analyzed for ash yield, petrographic composition, low-temperature ash mineralogy and palynomorph abundances. Abundance profiles were constructed for ash, 12 petrographic components, 3 minerals and 5 miospore assemblages. The profiles and calculated correlation coefficients show close relationships between several constituents. Components that increased in abundance upward in the coal bed were a collinite type > 50 microns in thickness, cutinite, and miospores affiliated with calamites, herbaceous lycopods, cordaites and herbaceous ferns. Components that decreased in abundance upward were a collinite type 50 ??m in thickness, cutinite, calamite and cordaite miospores and kaolinite. Significant correlations occurred between ash yield and the collinite types > 50 and < 50 ??m in thickness but no significant correlation was found between ash yield and total vitrinite-group content. This is interpreted to show that division of vitrinite macerals by size is important in petrographic paleoenvironmental studies. Paleoecologic interpretations based upon these correlations suggest that two distinct, planar, probably topogenous paleoecologic environments are represented in this column of the Redstone coal. The lower two-thirds of the coal bed was interpreted to have accumulated in a planar swamp in which significant introduction of detrital or dissolved mineral matter, and significant anaerobic and moderate oxidative degradation of the peat occurred. The flora of this paleoenvironment was dominated by tree ferns. The paleoenvironment during accumulation of the upper one-third of the coal bed was also interpreted to have been a planar swamp, but one in which moderate to low introduction of detrital or dissolved mineral matter, and minor anaerobic and oxidative degradation of the peat occurred. The dominant flora of this paleoenvironment consisted mainly of calamites with fewer cordaites and herbaceous ferns. This study shows that valuable paleoecologic information may be obtained by sampling closely spaced vertical increments. No mixing of detrital sediments with the peat was observed in coal layers immediately adjacent to the parting or the overlying sandstone unit. ?? 1990.

Peatlands and potatoes; organic wetland soils in Uganda

NASA Astrophysics Data System (ADS)

Farmer, Jenny; Langan, Charlie; Gimona, Alessandro; Poggio, Laura; Smith, Jo

2017-04-01

Land use change in Uganda's wetlands has received very little research attention. Peat soils dominate the papyrus wetlands of the south west of the country, but the areas they are found in have been increasingly converted to potato cultivation. Our research in Uganda set out to (a) document both the annual use of and changes to these soils under potato cultivation, and (b) the extent and condition of these soils across wetland systems. During our research we found it was necessary to develop locally appropriate protocols for sampling and analysis of soil characteristics, based on field conditions and locally available resources. Over the period of one year we studied the use of the peat soil for potato cultivation by smallholder farmers in Ruhuma wetland and measured changes to surface peat properties and soil nutrients in fields over that time. Farmer's use of the fields changed over the year, with cultivation, harvesting and fallow periods, which impacted on soil micro-topography. Measured soil properties changed over the course of the year as a result of the land use, with bulk density, nitrogen content, potassium and magnesium all reducing. Comparison of changes in soil carbon stocks over the study period were difficult to make as it was not possible to reach the bottom of the peat layer. However, a layer of fallow weeds discarded onto the soil prior to preparation of the raised potato beds provided a time marker which gave insight into carbon losses over the year. To determine the peatland extent, a spatial survey was conducted in the Kanyabaha-Rushebeya wetland system, capturing peat depths and key soil properties (bulk density, organic matter and carbon contents). Generalised additive models were used to map peat depth and soil characteristics across the system, and maps were developed for these as well as drainage and land use classes. Comparison of peat cores between the two study areas indicates spatial variability in peat depths and the influence of neighbouring mineral soil hillslopes. Our work provides valuable insight into the condition and use of these tropical peat soils, which are under-researched yet highly depended upon by local communities, with wider climate impacts. Cultivation of these peat soils has implications for their future sustainability and use, and having insight into the impacts of land management on these soils improves local and national level capacity for better soil management.

Losses of Soil Carbon upon a Fire on a Drained Forested Raised Bog

NASA Astrophysics Data System (ADS)

Glukhova, T. V.; Sirin, A. A.

2018-05-01

We studied the consequences of a fire that affected 29 ha of a drained forested raised bog in Tver oblast, Central European Russia. The drainage network consisted of open 1-m-deep ditches with 60 to 160 m ditch spacing. The groundwater level (GWL) varied within the studied drained bog. We used the method of assessing the loss of soil carbon (C) based on the difference between the ash concentration in the burnt peat of the upper layer and underlying unburnt layers. The carbon loss was higher near the drainage ditches than in the sites remote from ditches. The sample median values of carbon loss (kg C/m2) were estimated at 0.37 near the drainage ditches and at 0.22 for the remote sites with a distance of 160 m between ditches. They increased to 2.23 and 0.79 near and far from the drainage ditches for 106 m ditch spacing, and ranged from 1.13 to 2.10 near the drainage ditches and were equal to 0.45 at the remote sites for 60 m ditch spacing. The maximum loss of C was at the bog margin with the 70-cm-deep GWL; the sample median was equal to 2.97 kg C/m2. The results obtained for C loss from the wildfire on the raised bog agree with the estimates obtained by other authors (1.45-4.90 kg C/m2) and confirm the importance of taking such loss into account in the estimates of the carbon budget of peat soils (Histosols).

Dissolved organic carbon in soil solution of peat-moorsh soils on Kuwasy Mire

NASA Astrophysics Data System (ADS)

Jaszczyński, J.; Sapek, A.

2009-04-01

Key words: peat-moorsh soils, soil solution, dissolved organic carbon (DOC), temperature of soil, redox potential. The objective this study was the dissolved organic carbon concentration (DOC) in soil solution on the background of soil temperature, moisture and redox potential. The investigations were localized on the area of drained and agricultural used Kuwasy Mire, which are situated in the middle basin of Biebrza River, in North-East Poland. Research point was placed on a low peat soil of 110 cm depth managed as extensive grassland. The soil was recognized as peat-moorsh with the second degree of the moorshing process (with 20 cm of moorsh layer). The ceramic suction cups were installed in three replications at 30 cm depth of soil profile. The soil solution was continuously sampled by pomp of the automatic field station. The successive samples comprised of solution collected at the intervals of 21 days. Simultaneously, at the 20, 30 and 40 cm soil depths the measurements of temperature and determination of soil moisture and redox potential were made automatically. The mean twenty-four hours data were collected. The concentrations of DOC were determined by means of the flow colorimeter using the Skalar standard methods. Presented observations were made in 2001-2006. Mean DOC concentration in soil solution was 66 mg.dm-3 within all research period. A significant positive correlation between studied compound concentration and temperature of soil at 30 cm depth was observed; (correlation coefficient - r=0.55, number of samples - n=87). The highest DOC concentrations were observed during the season from July to October, when also a lower ground water level occurred. The DOC concentration in soil solution showed as well a significant correlation with the soil redox potential at 20 cm level. On this depth of describing soil profile a frontier layer between moorshing layer and peat has been existed. This layer is the potentially most active in the respect to biochemical transformation. On the other hand it wasn't possible to shown dependences on the DOC concentration from soil moisture. That probably results from a huge water-holding capacity of these type of peat soils, which are keeping a high moisture content even at a long time after decreasing of the groundwater table.

The influence of aeration and temperature on the structure of bacterial complexes in high-moor peat soil

NASA Astrophysics Data System (ADS)

Kukharenko, O. S.; Pavlova, N. S.; Dobrovol'Skaya, T. G.; Golovchenko, A. V.; Pochatkova, T. N.; Zenova, G. M.; Zvyagintsev, D. G.

2010-05-01

The number and taxonomic structure of the heterotrophic block of aerobic and facultative anaerobic bacteria were studied in monoliths from a high-moor peat (stored at room temperature and in a refrigerator) and in the peat horizons mixed in laboratory vessels. The monitoring lasted for a year. In the T0 horizon, spirilla predominated at room and low temperatures; in the T1 and T2 horizons, bacilli were the dominants. The continuous mixing of the peat layers increased the oxygen concentration and the peat decomposition; hence, the shares of actinomycetes and bacilli (bacteria of the hydrolytic complex) increased. In the peat studied, the bacilli were in the active state; i.e., vegetative cells predominated, whose amount ranged from 65 to 90%. The representatives of the main species of bacilli (the facultative anaerobic forms prevailed) hydrolyzed starch, pectin, and carboxymethylcellulose. Thus, precisely sporiferous bacteria can actively participate in the decomposition of plant polysaccharides in high-moor peat soils that are characterized by low temperatures and an oxygen deficit. The development of actinomycetes is inhibited by low temperatures; they can develop only under elevated temperature and better aeration.

Degradation of Malaysian peatlands decreases levels of phenolics in soil and in leaves of Macaranga pruinosa

NASA Astrophysics Data System (ADS)

Yule, Catherine; Lim, Yau; Lim, Tse

2016-04-01

Indo-Malaysian tropical peat swamp forests (PSF) sequester enormous stores of carbon in the form of phenolic compounds, particularly lignin as well as tannins. These phenolic compounds are crucial for ecosystem functioning in PSF through their inter-related roles in peat formation and plant defenses. Disturbance of PSF causes destruction of the peat substrate, but the specific impact of disturbance on phenolic compounds in peat and its associated vegetation has not previously been examined. A scale was developed to score peatland degradation based on the three major human impacts that affect tropical PSF - logging, drainage and fire. The objectives of this study were to compare the amount of phenolic compounds in Macaranga pruinosa, a common PSF tree, and in the peat substrate along a gradient of peatland degradation from pristine peat swamp forest to cleared, drained and burnt peatlands. We examined phenolic compounds in M. pruinosa and in peat and found that levels of total phenolic compounds and total tannins decrease in the leaves of M.pruinosa and also in the surface peat layers with an increase in peatland degradation. We conclude that waterlogged conditions preserve the concentration of phenolic compounds in peat, and that even PSF that has been previously logged but which has recovered a full canopy cover will have high levels of total phenolic content (TPC) in peat. High levels of TPC in peat and in the flora are vital for the inhibition of decomposition of organic matter and this is crucial for the accretion of peat and the sequestration of carbon. Thus regional PSF flourish despite the phenolic rich, toxic, waterlogged, nutrient poor, conditions, and reversal of such conditions is a sign of degradation.

Mechanisms controlling Cu, Fe, Mn, and Co profiles in peat of the Filson Creek Fen, northeastern Minnesota

USGS Publications Warehouse

Walton-Day, K.; Filipek, L.H.; Papp, C.S.E.

1990-01-01

Filson Creek Fen, located in northeastern Minnesota, overlies a Cu-Ni sulfide deposit. A site in the fen was studied to evaluate the hydrogeochemical mechanisms governing the development of Fe, Mn, Co, and Cu profiles in the peat. At the study site, surface peat approximately 1 m thick is separated from the underlying mineralized bedrock by a 6-12 m thickness of lake and glaciofluvial sediments and till. Concentrations of Fe, Mn, Co, and Cu in peat and major elements in pore water delineate a shallow, relatively oxidized, Cu-rich zone overlying a deeper, reduced, Fe-, Mn-, and Co-rich zone within the peat. Sequential metal extractions from peat samples reveal that 40-55% of the Cu in the shallow zone is associated with organic material, whereas the remaining Cu is distributed between iron-oxide, sulfide, and residual fractions. Sixty to seventy percent of the Fe, Mn, and Co concentrated in the deeper zone occur in the residual phase. The metal profiles and associations probably result from non-steady-state input of metals and detritus into the fen during formation of the peat column. The enrichment of organic-associated Cu in the upper, oxidized zone represents a combination of Cu transported into the fen with detrital plant fragments and soluble Cu, derived from weathering of outcrop and subcrop of the mineral deposit, transported into the fen, and fixed onto organic matter in the peat. The variable stratigraphy of the peat indicates that weathering processes and surface vegetation have changed through time in the fen. The Fe, Mn, and Co maxima at the base of the peat are associated with a maximum in detrital matter content of the peat resulting from a transition between the underlying inorganic sedimentary environment to an organic sedimentary environment. The chemistry of sediments and ground water collected beneath the peat indicate that mobilization of metals from sulfide minerals in the buried mineral deposit or glacial deposits is minimal. Therefore, the primary source of Cu to the peat at the study site is outcrops and shallow subcrops of the mineral deposit adjacent to the fen. ?? 1990.

Spatial Heterogeneity in the Properties of High-Moor Peat Soils under Local Pyrogenesis in Northeastern Sakhalin

NASA Astrophysics Data System (ADS)

Lipatov, D. N.; Shcheglov, A. I.; Manakhov, D. V.; Brekhov, P. T.

2016-02-01

The structure and properties of oligotrophic peat, oligotrophic peat gley, and pyrogenic oligotrophic peat soils identified on a plot 0.5 km2 in area in the northeast of Sakhalin Island have been studied. The vertical distributions of physicochemical, chemical, and ecotoxicological parameters in the profiles of some bog soil groups have been considered. An increase in ash content, a less acid reaction, and a deficit of available nitrogen and potassium have been revealed in the upper horizons of pyrogenic soils. No accumulation of mobile heavy metals is manifested in the pyrogenic horizons of peat soils. Statistical parameters of the spatial variation in pHKCl and total acidity, as well as the contents of ash, available phosphorus, exchangeable potassium, ammonium and nitrate nitrogen, mobile heavy metals (Cr, Ni, Cu, Zn, Cd, Pb), and benzo[ a]pyrene, have been calculated for the moss and sublitter horizons. The variation coefficients are 30-100% for most of the studied parameters and reach 100-200% for available phosphorus; ammonium nitrogen; and mobile Ni, Cu, Zn, and Cd. An increase in the content of benzo[ a]pyrene, although without MPC exceedance, is noted in the moss of pyrogenic soils and the peat horizons untouched by fires.

Petrography and geochemistry of selected lignite beds in the Gibbons Creek mine (Manning Formation, Jackson Group, Paleocene) of east-central Texas

USGS Publications Warehouse

Warwick, Peter D.; Crowley, Sharon S.; Ruppert, Leslie F.; Pontolillo, James

1997-01-01

This study examined the petrographic and geochemical characteristics of two lignite beds (3500 and 4500 beds, Manning Formation, Jackson Group, Eocene) that are mined at the Gibbons Creek mine in east-central Texas. The purpose of the study was to identify the relations among sample ash yield, coal petrography, and trace-element concentrations in lignite and adjoining rock layers of the Gibbons Creek mine. Particular interest was given to the distribution of 12 environmentally sensitive trace elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) that have been identified as potentially hazardous air pollutants (HAPs) in the United States Clean Air Act Amendments of 1990. Eleven lignite, floor, and rock parting samples were collected from incremental channel samples of the 3500 and 4500 beds that were exposed in a highwall of pit A3 at the Gibbons Creek mine. Short proximate and ultimate and forms of sulfur analyses were performed on all lignite samples, and lignite and rock samples were analyzed for 60 major, minor and trace elements. Representative splits of all lignite samples were ground and cast into pellets, and polished for petrographic analyses in blue-light fluorescence and reflected white light to determine liptinite, inertinite, and huminite maceral group percentages. The following observations summarize our results and conclusions about the geochemistry, petrography, and sedimentology of the 3500 and 4500 beds of the Gibbons Creek lignite deposit: (1) Weighted average dry (db) ash yield for the two beds is 29.7%, average total sulfur content is 2.6%, and average calorific value is 7832 Btu (18.22 MJ/kg). Ash yields are greatest in the lower bench (59.33% db) of the 3500 bed and in the upper bench of the 4500 bed (74.61% db). (2) For lignite samples (on a whole-coal basis), the distributions of two of the HAPs (Pb and Sb) are positively related to ash yield, probably indicating an inorganic affinity for these elements. By using cluster analysis we found that Be and Cd were poorly associated with ash yield, indicating a possible organic affinity, and that Ni, Se, Hg, U, and Pb cluster with most of the rare-earth elements. (3) The dominance of the crypto-eugelinite maceral subgroup over the crypto-humotelinite subgroup suggests that all Gibbons Creek lignites were subjected to peat-forming conditions (either biogenic or chemical) conducive to the degradation of wood cellular material into matrix gels, or that original plant material was not very woody and was prone to formation of matrix gels. The latter idea is supported by pollen studies of Gibbons Creek lignite beds; results indicate that the peat was derived in part from marsh plants low in wood tissue. (4) The occurrence of siliceous sponge spicules in the lower benches of the 3500 bed suggests the original peat in this part of the bed was deposited in standing, fresh water. (5) The petrographic data indicate that the upper sample interval of the 3500 bed contains more inertinite (3%) than the other samples studied. Increases in inertinite content in the upper part of the 3500 bed may have been associated with alteration of the peat by acids derived from the volcanic ash or could have been caused by fire, oxidation and drying, or biologic alteration of the peat in the paleo-mire.

The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources

NASA Astrophysics Data System (ADS)

Ritson, Jonathan P.; Brazier, Richard E.; Graham, Nigel J. D.; Freeman, Chris; Templeton, Michael R.; Clark, Joanna M.

2017-06-01

Drought conditions are expected to increase in frequency and severity as the climate changes, representing a threat to carbon sequestered in peat soils. Downstream water treatment works are also at risk of regulatory compliance failures and higher treatment costs due to the increase in riverine dissolved organic carbon (DOC) often observed after droughts. More frequent droughts may also shift dominant vegetation in peatlands from Sphagnum moss to more drought-tolerant species. This paper examines the impact of drought on the production and treatability of DOC from four vegetation litters (Calluna vulgaris, Juncus effusus, Molinia caerulea and Sphagnum spp.) and a peat soil. We found that mild droughts caused a 39.6 % increase in DOC production from peat and that peat DOC that had been exposed to oxygen was harder to remove by conventional water treatment processes (coagulation/flocculation). Drought had no effect on the amount of DOC production from vegetation litters; however large variation was observed between typical peatland species (Sphagnum and Calluna) and drought-tolerant grassland species (Juncus and Molinia), with the latter producing more DOC per unit weight. This would therefore suggest the increase in riverine DOC often observed post-drought is due entirely to soil microbial processes and DOC solubility rather than litter layer effects. Long-term shifts in species diversity may, therefore, be the most important impact of drought on litter layer DOC flux, whereas pulses related to drought may be observed in peat soils and are likely to become more common in the future. These results provide evidence in support of catchment management which increases the resilience of peat soils to drought, such as ditch blocking to raise water tables.

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

NASA Astrophysics Data System (ADS)

Samson-Do, Myriam; St-Hilaire, André

2015-04-01

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

Pb inventory in an ombrotrophic bog decreases over time

NASA Astrophysics Data System (ADS)

Baumann, E.; Jeremiason, J.; Sebestyen, S.

2016-12-01

Peat cores were collected from the S2 ombrotrophic bog at the Marcell Experimental Forest (MEF) to determine if the Pb inventory in the bog has decreased over time. Pb concentrations in the outflow of the bog measured from 2009-2016 indicated continued mobilization and export of Pb out of the bog despite dramatic decreases in atmospheric deposition. A seminal study conducted by Urban et al. (1990) from 1981-1983 calculated a mass balance of Pb in the S2 watershed which included a Pb inventory in peat based on the approximate time frame of 1930 to 1983. We collected peat cores in 2016 to compare peat inventories of Pb over the same time range. We found that Pb inventories in the peat have decreased over time, consistent with Pb being mobilized by dissolved organic carbon (DOC) and gradually flushed out of the bog. Since 1983, DOC levels may have increased leading to further Pb mobilization and transport from the bog, but this trend is unclear. In contrast to Pb concentrations in the outflow water, upland runoff and the surface sphagnum moss layer have dramatically lower Pb concentrations compared to 1980s levels indicating fast ecosystem responses to a decrease in Pb inputs in these compartments. However, the deeper peat layers near the water table are responding more slowly to the decrease in Pb inputs and historical Pb inputs continue to be mobilized and transported from the bog. Our results would be applicable to other trace metals, such as Hg, that bind strongly to DOC. For example, a dramatic decrease in Hg deposition would not result in near-term decreases in Hg out of the bog.

The composition and character of DOM from an upland peat catchment - sources, roles and fate

NASA Astrophysics Data System (ADS)

Worrall, F.; Moody, C.; Clay, G.; Boothroyd, I.; Burt, T. P.

2017-12-01

The fluvial fluxes of dissolved organic carbon (DOC) from peatlands form an important part of that ecosystem's carbon cycle, contributing approximately 35% of the overall peatland carbon budget. The source, role and fate of this component of the carbon cycle was explored for a peat covered catchment in the north east of England with dissolved organic matter (DOM) being sampled from both a first-order peat-hosted stream and soil water at two depths within the peat profile. All DOM samples were analysed within the context of analysing the particulate organic matter (POM) from the catchment; the peat profile; and biomass. All samples were analysed using: elemental analysis (C, H, N, O, P and S); bomb calorimetry; thermogravimetric analysis (TGA); 13C solid state NMR; and S isotopes. Furthermore, the degradation of fresh DOC was examined over periods of 70 hours every month for 23 months. The analysis has shown that: DOM is highly oxidised compared to all other organic in the ecosystem and DOM did not exist until [C]/[O] < 1.44. The DOM was dominantly the product of lignin breakdown and not the processing of proteins or carbohydrates, i.e. it was not an intermediate of oxidation to CO2. DOM could only be sourced from high in the peat profile at most above 41 cm depth. Thermodynamic inhibition shows that only DOM from the surface layers could be reactive in the catotelmic layers of the peat. There was a significant role for the composition of the DOM in controlling degradation with degradation rates significantly increasing with the proportion of aldehyde and carboxylic acid functional groups but decreasing with the proportion of N-alkyl functional groups. The study meant that is was possible to consider the behaviour of DOM in terms of its thermodynamic properties (DH, DS & DG) for both formation and reaction.

Dissolved organic carbon concentrations and compositions, and trihalomethane formation potentials in waters from agricultural peat soils, Sacramento-San Joaquin Delta, California; implications for drinking-water quality

USGS Publications Warehouse

Fujii, Roger; Ranalli, Anthony J.; Aiken, George R.; Bergamaschi, Brian A.

1998-01-01

Water exported from the Sacramento-San Joaquin River delta (Delta) is an important drinking-water source for more than 20 million people in California. At times, this water contains elevated concentrations of dissolved organic carbon and bromide, and exceeds the U.S. Environmental Protection Agency's maximum contaminant level for trihalomethanes of 0.100 milligrams per liter if chlorinated for drinking water. About 20 to 50 percent of the trihalomethane precursors to Delta waters originates from drainage water from peat soils on Delta islands. This report elucidates some of the factors and processes controlling and affecting the concentration and quality of dissolved organic carbon released from peat soils and relates the propensity of dissolved organic carbon to form trihalomethanes to its chemical composition.Soil water was sampled from near-surface, oxidized, well-decomposed peat soil (upper soil zone) and deeper, reduced, fibrous peat soil (lower soil zone) from one agricultural field in the west central Delta over 1 year. Concentrations of dissolved organic carbon in the upper soil zone were highly variable, with median concentrations ranging from 46.4 to 83.2 milligrams per liter. Concentrations of dissolved organic carbon in samples from the lower soil zone were much less variable and generally slightly higher than samples from the upper soil zone, with median concentrations ranging from 49.3 to 82.3 milligrams per liter. The dissolved organic carbon from the lower soil zone had significantly higher aromaticity (as measured by specific ultraviolet absorbance) and contained significantly greater amounts of aromatic humic substances (as measured by XAD resin fractionation and carbon-13 nuclear magnetic resonance analysis of XAD isolates) than the dissolved organic carbon from the upper soil zone. These results support the conclusion that more aromatic forms of dissolved organic carbon are produced under anaerobic conditions compared to aerobic conditions. Dissolved organic carbon concentration, trihalomethane formation potential, and ultraviolet absorbance were all highly correlated, showing that trihalomethane precursors increased with increasing dissolved organic carbon and ultraviolet absorbance for whole water samples. Contrary to the generally accepted conceptual model for trihalomethane formation that assumes that aromatic forms of carbon are primary precursors to trihalomethanes, results from this study indicate that dissolved organic carbon aromaticity appears unrelated to trihalomethane formation on a carbon-normalized basis. Thus, dissolved organic carbon aromaticity alone cannot fully explain or predict trihalomethane precursor content, and further investigation of aromatic and nonaromatic forms of carbon will be needed to better identify trihalomethane precursors.

Nitrogen and phosphorus loading from drained wetlands adjacent to Upper Klamath and Agency lakes, Oregon

USGS Publications Warehouse

Snyder, Daniel T.; Morace, Jennifer L.

1997-01-01

The results of this study could be useful in helping to prioritize which drained wetlands may provide the greatest benefits with regard to reducing nutrient loads to the lake if restoration or land-use modifications are instituted. Recent acquisition and planned restoration of drained wetland areas at the Wood River and Williamson River North properties may produce significant reduction in the quantity of nutrients released by the decomposition of peat soils of these areas. If the water table rises to predrainage levels, the peats soils may become inundated most of the year, resulting in the continued long-term storage of nutrients within the peat soils by reducing aerobic decomposition. The maximum benefit, in terms of decreasing potential nutrient loss due to peat decomposition, could be the reduction of total nitrogen and total phosphorus loss to about one-half that of the 1994–95 annual loss estimated for all the drained wetlands sampled for this study.

Assessing tungsten transport in the vadose zone: from dissolution studies to soil columns.

PubMed

Tuna, Gulsah Sen; Braida, Washington; Ogundipe, Adebayo; Strickland, David

2012-03-01

This study investigates the dissolution, sorption, leachability, and plant uptake of tungsten and alloying metals from canister round munitions in the presence of model, well characterized soils. The source of tungsten was canister round munitions, composed mainly of tungsten (95%) with iron and nickel making up the remaining fraction. Three soils were chosen for the lysimeter studies while four model soils were selected for the adsorption studies. Lysimeter soils were representatives of the typical range of soils across the continental USA; muck-peat, clay-loamy and sandy-quartzose soil. Adsorption equilibrium data on the four model soils were modeled with Langmuir and linear isotherms and the model parameters were obtained. The adsorption affinity of soils for tungsten follows the order: Pahokee peat>kaolinite>montmorillonite>illite. A canister round munition dissolution study was also performed. After 24 d, the measured dissolved concentrations were: 61.97, 3.56, 15.83 mg L(-1) for tungsten, iron and nickel, respectively. Lysimeter transport studies show muck peat and sandy quartzose soils having higher tungsten concentration, up to 150 mg kg(-1) in the upper layers of the lysimeters and a sharp decline with depth suggesting strong retardation processes along the soil profile. The concentrations of tungsten, iron and nickel in soil lysimeter effluents were very low in terms of posing any environmental concern; although no regulatory limits have been established for tungsten in natural waters. The substantial uptake of tungsten and nickel by ryegrass after 120 d of exposure to soils containing canister round munition suggests the possibility of tungsten and nickel entering the food chain. Copyright © 2011 Elsevier Ltd. All rights reserved.

The temperature characteristics of biological active period of the peat soils of Bakchar swamp

NASA Astrophysics Data System (ADS)

Kiselev, M. V.; Dyukarev, E. A.; Voropay, N. N.

2018-01-01

The results of the study of the peculiarities of the temperature regime in the five basic ecosystems of oligotrophic bogs in the south taiga zone of Western Siberia in 2011-2016 are presented. The soil temperature regime was studied using the atmospheric-soil measuring complex at different depths from surface to 240 cm. All sites were divided into two groups according the bog water level: flooded sites (hollow and open fen) and drained sites (ridge, tall and low ryam). Waterlogged sites are better warmed in the summer period, and slowly freeze in the winter period. The analysis of the annual cycle of temperature showed that the maximum surface temperature is observed in July. The minimum temperature on the surface observed in February or January. The greatest temperature gradient was recorded in the upper 2 cm layer. The gradient at the open fen was -2 °C·cm-1 in February and 1.1 °C·cm-1 in October. The peak of formation of the seasonally frozen layer occurs at the end of autumn, beginning of winter. The degradation of the seasonally frozen layer was observed both from top and bottom, but degradation from the top is faster.

Depositional environments of the Jurassic Maghara main coal seam in north central Sinai, Egypt

NASA Astrophysics Data System (ADS)

Edress, Nader Ahmed Ahmed; Opluštil, Stanislav; Sýkorová, Ivana

2018-04-01

Twenty-eight channel samples with a cumulative thickness of about 4 m collected from three sections of the Maghara main coal seam in the middle Jurassic Safa Formation have been studied for their lithotype and maceral compositions to reconstruct the character of peat swamp, its hydrological regime and the predominating type of vegetation. Lithotype composition is a combination of dully lithotypes with duroclarain (19% of total cumulative thickness), clarodurain (15%), black durain (15%), and shaly coal (15%) and bright lithotypes represented by clarain (23%), vitrain (12%) and a small proportion of wild fire-generated fusain (1%). Maceral analyses revealed the dominance of vitrinite (70.6% on average), followed by liptinite (25.2%) and inertinite (8.1%). Mineral matter content is ∼9% on average and consists of clay, quartz and pyrite concentrate mostly at the base and the roof of the seam. Dominantly vitrinite composition of coal and extremely low fire- and oxidation-borne inertinite content, together with high Gelification Indices imply predomination of waterlogged anoxic conditions in the precursing mire with water tables mostly above the peat surface throughout most of the time during peat swamp formation. Increases in collotelinite contents and Tissue Preservation Index up the section, followed by a reversal trend in upper third of the coal section, further accompanied by a reversal trend in collodetrinite, liptodetrinite, alginite, sporinite and clay contents records a transition from dominately limnotelmatic and limnic at the lower part to dominately limnotelmatic with increase telmatic condition achieved in the middle part of coal. At the upper part of coal seam an opposite trend marks the return to limnic and limnotelmatic conditions in the final phases of peat swamp history and its subsequent inundation. The proportion of arborescent (mostly coniferous) and herbaceous vegetation varied throughout the section of the coal with tendency of increasing density of arborescent vegetation to the middle part of the coal seam section. The intercalation of coal in shallow marine strata implies that peat swamp precursor formed in a coastal setting, probably on delta plain or lagoon. Its formation was controlled by water table changes driven by sea level fluctuations that created an accommodation space necessary for preservation of peat.

The wettability of selected organic soils in Poland

NASA Astrophysics Data System (ADS)

Całka, A.; Hajnos, M.

2009-04-01

The wettability was measured in the laboratory by means of two methods: Water Drop Penetration Time (WDPT) test and Thin Column Wicking (TCW) method. WDPT is fast and simple method and was used to investigate potential water repellency of analyzed samples. TCW is an indirect method and was used to determine contact angles and surface free energy components. The measurement was performed in horizontal teflon chambers for thin-layer chromatography, adapted for tubes 10 cm long. The experiment was carried out on muck soils (samples were taken from two levels of soil profile: 0-20 cm and 20-40 cm) and peat soils. There were two types of peats: low-moor peats and high moor peats. Samples of low-moor peats were taken from level 25-75 cm (alder peat) and 75-125cm (sedge peat) and 25-75 cm (peloid peat). Samples of high moor peats from level 25-175 cm (sphagnum peat) and 175-225 cm (sphagnum peat with Eriophorum). There was found no variability in persistence of potential water repellency but there were differences in values of contact angles of individual soil samples. Both muck and peat samples are extremely water repellent soils. Water droplets persisted on the surface of soils for more than 24 hours. Contact angles and surface free energy components for all samples were differentiated. Ranges of water contact angles for organic soils are from 27,54o to 96,50o. The highest values of contact angles were for sphagnum peats, and the lowest for muck soil from 20-40 cm level. It means, that there are differences in wettability between these samples. Muck soil is the best wettable and sphagnum peats is the worst wettable soil. If the content of organic compounds in the soil exceeds 40% (like in peats), the tested material displays only dispersion-type interactions. Therefore for peat soils, the technique of thin column wicking could only be used to determine the dispersive component γiLW. For muck soils it was also determined electron-acceptor (Lewis acid) γ+ and electron-donor (Lewis base) γ- surface free energy components. The authors gratefully acknowledge the Ministry of Science and Higher Education for financial support of this work (grant No. N N310 149335).

Climatic Drivers for Multi-Decadal Shifts in Solute Transport and Methane Production Zones within a Large Peat Basin

NASA Technical Reports Server (NTRS)

Glaser, Paul H.; Siegel, Donald I.; Chanton, Jeffrey P.; Reeve, Andrew S.; Rosenberry, Donald O.; Corbett, J. Elizabeth; Dasgupta, Soumitri; Levy, Zeno

2016-01-01

Northern peatlands are an important source for greenhouse gases but their capacity to produce methane remains uncertain under changing climatic conditions. We therefore analyzed a 43-year time series of pore-water chemistry to determine if long-term shifts in precipitation altered the vertical transport of solutes within a large peat basin in northern Minnesota. These data suggest that rates of methane production can be finely tuned to multi-decadal shifts in precipitation that drive the vertical penetration of labile carbon substrates within the Glacial Lake Agassiz Peatlands. Tritium and cation profiles demonstrate that only the upper meter of these peat deposits was flushed by downwardly moving recharge from 1965 through 1983 during a Transitional Dry-to-Moist Period. However, a shift to a moister climate after 1984 drove surface waters much deeper, largely flushing the pore waters of all bogs and fens to depths of 2 m. Labile carbon compounds were transported downward from the rhizosphere to the basal peat at this time producing a substantial enrichment of methane in Delta C-14 with respect to the solid-phase peat from 1991 to 2008. These data indicate that labile carbon substrates can fuel deep production zones of methanogenesis that more than doubled in thickness across this large peat basin after 1984. Moreover, the entire peat profile apparently has the capacity to produce methane from labile carbon substrates depending on climate-driven modes of solute transport. Future changes in precipitation may therefore play a central role in determining the source strength of peatlands in the global methane cycle.

Climatic drivers for multidecadal shifts in solute transport and methane production zones within a large peat basin

USGS Publications Warehouse

Glaser, Paul H.; Siegel, Donald I.; Chanton, Jeffrey P.; Reeve, Andrew S.; Rosenberry, Donald O.; Corbett, J. Elizabeth; Dasgupta, Soumitri; Levy, Zeno

2016-01-01

Northern peatlands are an important source for greenhouse gases, but their capacity to produce methane remains uncertain under changing climatic conditions. We therefore analyzed a 43 year time series of the pore-water chemistry to determine if long-term shifts in precipitation altered the vertical transport of solutes within a large peat basin in northern Minnesota. These data suggest that rates of methane production can be finely tuned to multidecadal shifts in precipitation that drive the vertical penetration of labile carbon substrates within the Glacial Lake Agassiz Peatlands. Tritium and cation profiles demonstrate that only the upper meter of these peat deposits was flushed by downwardly moving recharge from 1965 to 1983 during a Transitional Dry-to-Moist Period. However, a shift to a moister climate after 1984 drove surface waters much deeper, largely flushing the pore waters of all bogs and fens to depths of 2 m. Labile carbon compounds were transported downward from the rhizosphere to the basal peat at this time producing a substantial enrichment of methane in Δ14C with respect to the solid-phase peat from 1991 to 2008. These data indicate that labile carbon substrates can fuel deep production zones of methanogenesis that more than doubled in thickness across this large peat basin after 1984. Moreover, the entire peat profile apparently has the capacity to produce methane from labile carbon substrates depending on climate-driven modes of solute transport. Future changes in precipitation may therefore play a central role in determining the source strength of peatlands in the global methane cycle.

Calibrated Hydrothermal Parameters, Barrow, Alaska, 2013

DOE Data Explorer

Atchley, Adam; Painter, Scott; Harp, Dylan; Coon, Ethan; Wilson, Cathy; Liljedahl, Anna; Romanovsky, Vladimir

2015-01-29

A model-observation-experiment process (ModEx) is used to generate three 1D models of characteristic micro-topographical land-formations, which are capable of simulating present active thaw layer (ALT) from current climate conditions. Each column was used in a coupled calibration to identify moss, peat and mineral soil hydrothermal properties to be used in up-scaled simulations. Observational soil temperature data from a tundra site located near Barrow, AK (Area C) is used to calibrate thermal properties of moss, peat, and sandy loam soil to be used in the multiphysics Advanced Terrestrial Simulator (ATS) models. Simulation results are a list of calibrated hydrothermal parameters for moss, peat, and mineral soil hydrothermal parameters.

Paleoenvironmental History of JoCo Marsh, Jamaica Bay, New York

NASA Technical Reports Server (NTRS)

Liberman, Louisa; Peteet, Dorothy; Hansen, James E. (Technical Monitor)

2001-01-01

Sediment cores from JoCo Marsh, located in Jamaica Bay, NY were analyzed for plant macrofossil and foraminifera records. These records reflect changes in vegetation, sea level, climate and human intervention. Better understanding of past environmental changes provides information for future preservation and protection of the estuary. A 2.81 m core was retrieved from JoCo, a high marsh area located on the eastern side of Jamaica Bay. The lithology of the core differs from high levels of sand, with small amounts of clay, in the bottom 0.8 meters, to salt marsh peat in the upper 2 meters of the core. Basal wood in the sand was dated to about 2060 yr BP. Elphidium foraminifera dominate the basal sands, along with Scirpus seeds, wood, and charcoal. These sands include fish scales which are tentatively identified as killifish, suggesting shallow pools. The transition to marsh peat is dominated by sedge seeds, and declines in charcoal. The peat appears to be dominated by salt marsh grasses. At 2 m the foraminifera change to include mainly Trochammina species and other undifferentiated agglutinates. The upper portion of the core is dominated by Salicornia seeds along with Trochammina and Miliammina or Quinqueloculia. The history of this marsh will be integrated with other records of marsh environmental change along the US eastern seaboard.

Water exchange in raised bogs: revised views especially in relation to biogeochemistry

NASA Astrophysics Data System (ADS)

Sirin, Andrey; Kravchenko, Irina; Yurova, Alla; Markina, Anastasiya

2017-04-01

Raised bogs are one of the most common and exciting mire type within the boreal zone and appear in the other zones including mountain regions in the tropics. They receive water and nutrients from the atmosphere and pore water stored in their domes is spaced above the surrounding area (up to 10 m in height). Traditionally it is assumed that water flow occurs mainly in a peat layer near to the surface and water transport is negligible in deeper layers (lvanov, 1981; Ingram, 1982; etc.). The «acrotelm/catotelm» paradigm on active and inert horizons for the peat above and below the lowest water level is still widely spread in peatland hydrology. However, recent studies have shown that deep water movement is much more dynamic in raised bogs than was previously thought (Sirin et al., 1997, Reeve et al., 2000; etc.). Relying on isotope studies we conclude that all the mounded strata of the raised bogs have relatively active water exchange although water residence time changes with depth. The study included two raised bogs, representing different typical hydrological conditions (underlain by outwash sands and moraine clay) at the Zapadnaya Dvina Peatland Field Station of the Institute of Forest Science RAS located 400 km west of Moscow (56 N, 32 E). Peatlands, among which raised bogs dominate, constitute > 30% of the area, and maximum peat thickness exceeds 7 m. To evaluate water residence time in peat strata specially determined mathematical model which include the equations of water mass and tritium balance, imbedded in a conceptual framework of water dynamics within a raised bog peat body, have been developed and tested. The results from isotope studies (3H, 18O, 2H) were additionally supported by geochemical (pH, Eh, electrical conductivity) and temperature long term monitoring, as well as dissolved CO2 and CH4 monitoring within vertical profiles of the studied raised bogs (Sirin et al., 1998). Later it was also supported by microbiology data of methane cycle in the profile of peat bogs (Kravchenko, Sirin, 2007). The obtained results confirm that the hydrological stratification of peat bogs is a more complicated picture than previously thought and need to be considered.

Sources and distribution of trace elements in Estonian peat

NASA Astrophysics Data System (ADS)

Orru, Hans; Orru, Mall

2006-10-01

This paper presents the results of the distribution of trace elements in Estonian mires. Sixty four mires, representative of the different landscape units, were analyzed for the content of 16 trace elements (Cr, Mn, Ni, Cu, Zn, and Pb using AAS; Cd by GF-AAS; Hg by the cold vapour method; and V, Co, As, Sr, Mo, Th, and U by XRF) as well as other peat characteristics (peat type, degree of humification, pH and ash content). The results of the research show that concentrations of trace elements in peat are generally low: V 3.8 ± 0.6, Cr 3.1 ± 0.2, Mn 35.1 ± 2.7, Co 0.50 ± 0.05, Ni 3.7 ± 0.2, Cu 4.4 ± 0.3, Zn 10.0 ± 0.7, As 2.4 ± 0.3, Sr 21.9 ± 0.9, Mo 1.2 ± 0.2, Cd 0.12 ± 0.01, Hg 0.05 ± 0.01, Pb 3.3 ± 0.2, Th 0.47 ± 0.05, U 1.3 ± 0.2 μg g - 1 and S 0.25 ± 0.02%. Statistical analyses on these large database showed that Co has the highest positive correlations with many elements and ash content. As, Ni, Mo, ash content and pH are also significantly correlated. The lowest abundance of most trace elements was recorded in mires fed only by precipitation (ombrotrophic), and the highest in mires fed by groundwater and springs (minerotrophic), which are situated in the flood plains of river valleys. Concentrations usually differ between the superficial, middle and bottom peat layers, but the significance decreases depending on the type of mire in the following order: transitional mires - raised bogs - fens. Differences among mire types are highest for the superficial but not significant for the basal peat layers. The use of peat with high concentrations of trace elements in agriculture, horticulture, as fuel, for water purification etc., may pose a risk for humans: via the food chain, through inhalation, drinking water etc.

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

PubMed

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

2015-05-01

Batch sorption experiments were conducted to evaluate the sorption behaviour of iodide and the microbial impact on iodide sorption in the surface moss, subsurface peat, gyttja, and clay layers of a nutrient-poor boreal bog. The batch distribution coefficient (Kd) values of iodide decreased as a function of sampling depth. The highest Kd values, 4800 L/Kg dry weight (DW) (geometric mean), were observed in the fresh surface moss and the lowest in the bottom clay (geometric mean 90 mL/g DW). In the surface moss, peat and gyttja layers, which have a high organic matter content (on average 97%), maximum sorption was observed at a pH between ∼ 4 and 5 and in the clay layer at pH 2. The Kd values were significantly lower in sterilized samples, being 20-fold lower than the values found for the unsterilized samples. In addition, the recolonization of sterilized samples with a microbial population from the fresh samples restored the sorption capacity of surface moss, peat and gyttja samples, indicating that the decrease in the sorption was due to the destruction of microbes and supporting the hypothesis that microbes are necessary for the incorporation of iodide into the organic matter. Anoxic conditions reduced the sorption of iodide in fresh, untreated samples, similarly to the effect of sterilization, which supports the hypothesis that iodide is oxidized into I2/HIO before incorporation into the organic matter. Furthermore, the Kd values positively correlated with peroxidase activity in surface moss, subsurface peat and gyttja layers at +20 °C, and with the bacterial cell counts obtained from plate count agar at +4 °C. Our results demonstrate the importance of viable microbes for the sorption of iodide in the bog environment, having a high organic matter content and a low pH. Copyright © 2015 Elsevier Ltd. All rights reserved.

Economic characteristics of the peat deposits of Costa Rica: preliminary study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, A.D. Malavassi, L.; Raymond, R. Jr.; Mora, S.

1985-01-01

Recent field and laboratory studies have established the presence of numerous extensive peat deposits in Costa Rica. Three of these were selected for initial investigation: (1) the cloud-forest histosols of the Talamanca Mountain Range; (2) the Rio Medio Queso flood plain deposits near the northern Costa Rican border; and (3) a tropical jungle swamp deposit on the northeastern coastal plain. In the Talamanca area, 29 samples were collected from eight sites. Due to the high moisture and cool temperatures of the cloud forest, the peats in this area form blanket-like deposits (generally <1 meter thick) over a wide area (>150more » km/sup 2/). These peats are all highly decomposed (avg. 28% fiber), high in ash (avg. 21%), and extensively bioturbated. Relative to all other sites visited, these peats are lowest in moisture (avg. 84%), pH (avg. 4.4), fixed carbon (avg. 23%), and sulfur (avg. 0.2%). However, they have the highest bulk densities (avg. 0.22 g/cc), volatile matter contents (avg. 55%), and nitrogen. Their heating value averaged 7700 BTUs/lb., dry. In the Rio Medio Queso area, 28 samples were collected, representing one transect of the 70 km/sup 2/ flood plain. The peats here occurred in several layers (each <1-1/2 meters thick), interfingering with river flood plain sediments. These peats have the highest calorific values (avg. 8000 BTUs/lb., dry), fixed carbon (avg. 30%), and ash (avg. 22%) and have an average pH of 5.4 and a bulk density of 0.20 g/cc. These results represent only the first part of a long-term, extensive survey of Costa Rica's peat resources. However, they suggest that large, economically-significant peat deposits may be present in this country. 5 refs., 8 figs., 4 tabs.« less

Methane ebullition fluxes from northern peatlands: initial observations from four sites of contrasting vegetation type in Caribou Bog, ME

NASA Astrophysics Data System (ADS)

Slater, L. D.; Comas, X.; Mumford, K. G.; Reeve, A. S.; Varner, R. K.; Chen, X.; Wright, W.; Wright, J.; Molnar, I. L.; Krol, M.

2017-12-01

The contribution of peatlands to the atmospheric CH4 burden remains unclear in large part due to incomplete understanding of the ebullition pathway. Oxidation of dissolved methane reduces the release of methane by diffusion, but the transit time of bubbles released via ebullition is too short for extensive oxidation to occur, i.e. ebullition releases increase the greenhouse gas potential of peatlands. We are working to couple innovative strategies for ebullition monitoring with a physical model describing gas transport in terms of the mechanical properties of the peat. This integration of measurement and modeling will permit a fundamental step forward towards a more quantitative understanding of CH4 ebullition from peatlands. Sampling and sensor installation have been performed in Caribou Bog, a multi-unit peatland located in Maine (USA) where an extensive database accounting for a decade of research is already available from previous work examining methane dynamics. Multi-depth gas trap and moisture probe arrays have been installed at four sites selected based on contrasting vegetation type and peat basin depth determined from extensive ground penetrating radar surveys. Hydraulic head measurements have also been acquired on multi-level piezometers designed to capture transient signals associated with gas transport. Cores and initial field observations acquired in summer 2017 confirm that the physical properties of the peat vary markedly between the sites and influence gas storage and release. An existing ebullition model describing gas bubble expansion is being coupled with an invasion percolation approach to describe the transport of CH4 between multiple peat layers by both diffusion in the pore water and ebullition between layers. Although the proposed model does not explicitly incorporate the geomechanical properties of peat, model predictions for maximum gas contents are being compared with key measurable geomechanical properties (including measured capillary drainage curves for peat) that may control ebullition.

In Place Soil Treatments for Prevention of Explosives Contamination

DTIC Science & Technology

2010-01-01

gallon plastic drums. Treatment Layer Preparation The PMSO mixture was prepared in a ratio of peat moss and crude soybean oil of 1:1 (w:w). The...PMSO was prepared in batches using a small tow-behind plastic drum gas cement mixer (9 cu. ft capacity). Peat moss bags were weighed, and then emptied...wrap (or other applicable shipping materials) and shipped in plastic coolers by a commercial carrier priority overnight in ice. Holding Times

Modelling the effect of the physical and chemical characteristics of the materials used as casing layers on the production parameters of Agaricus bisporus.

PubMed

Pardo, Arturo; Emilio Pardo, J; de Juan, J Arturo; Zied, Diego Cunha

2010-12-01

The aim of this research was to show the mathematical data obtained through the correlations found between the physical and chemical characteristics of casing layers and the final mushrooms' properties. For this purpose, 8 casing layers were used: soil, soil + peat moss, soil + black peat, soil + composted pine bark, soil + coconut fibre pith, soil + wood fibre, soil + composted vine shoots and, finally, the casing of La Rioja subjected to the ruffling practice. The conclusion that interplays in the fructification process with only the physical and chemical characteristics of casing are complicated was drawn. The mathematical data obtained in earliness could be explained in non-ruffled cultivation. The variability observed for the mushroom weight and the mushroom diameter variables could be explained in both ruffled and non-ruffled cultivations. Finally, the properties of the final quality of mushrooms were established by regression analysis.

Evaluating the hydraulic and transport properties of peat soil using pore network modeling and X-ray micro computed tomography

NASA Astrophysics Data System (ADS)

Gharedaghloo, Behrad; Price, Jonathan S.; Rezanezhad, Fereidoun; Quinton, William L.

2018-06-01

Micro-scale properties of peat pore space and their influence on hydraulic and transport properties of peat soils have been given little attention so far. Characterizing the variation of these properties in a peat profile can increase our knowledge on the processes controlling contaminant transport through peatlands. As opposed to the common macro-scale (or bulk) representation of groundwater flow and transport processes, a pore network model (PNM) simulates flow and transport processes within individual pores. Here, a pore network modeling code capable of simulating advective and diffusive transport processes through a 3D unstructured pore network was developed; its predictive performance was evaluated by comparing its results to empirical values and to the results of computational fluid dynamics (CFD) simulations. This is the first time that peat pore networks have been extracted from X-ray micro-computed tomography (μCT) images of peat deposits and peat pore characteristics evaluated in a 3D approach. Water flow and solute transport were modeled in the unstructured pore networks mapped directly from μCT images. The modeling results were processed to determine the bulk properties of peat deposits. Results portray the commonly observed decrease in hydraulic conductivity with depth, which was attributed to the reduction of pore radius and increase in pore tortuosity. The increase in pore tortuosity with depth was associated with more decomposed peat soil and decreasing pore coordination number with depth, which extended the flow path of fluid particles. Results also revealed that hydraulic conductivity is isotropic locally, but becomes anisotropic after upscaling to core-scale; this suggests the anisotropy of peat hydraulic conductivity observed in core-scale and field-scale is due to the strong heterogeneity in the vertical dimension that is imposed by the layered structure of peat soils. Transport simulations revealed that for a given solute, the effective diffusion coefficient decreases with depth due to the corresponding increase of diffusional tortuosity. Longitudinal dispersivity of peat also was computed by analyzing advective-dominant transport simulations that showed peat dispersivity is similar to the empirical values reported in the same peat soil; it is not sensitive to soil depth and does not vary much along the soil profile.

Linking major and trace element headwater stream concentrations to DOC release and hydrologic conditions in a bog and peaty riparian zone

NASA Astrophysics Data System (ADS)

Broder, Tanja; Biester, Harald

2017-04-01

Peatlands and organic-rich riparian zones are known to export large amounts of dissolved organic carbon (DOC) to surface water. In organic-rich, acidic headwater streams main carriers for element export are dissolved organic matter (DOM) and organic-iron complexes. In this environment DOM might also act as major carrier for metals, which otherwise may have a low solubility. This study examines annual and short term event-based variations of major and trace elements in a headwater catchment. Patterns are used to trace hydrological pathways and element sources under different hydrologic preconditions. Furthermore, it elucidates the importance of DOC as carrier of different elements in a bog and a peaty riparian catchment. The study was conducted in a small headwater stream draining an ombrotrophic peatland with an adjacent forested area with peaty riparian soils in the Harz Mountains (Germany). Discharge sampling was conducted weekly at two sites from snowmelt to begin of snowfall and in high resolution during selected discharge events in 2013 and 2014. Element concentrations were measured by means of ICP-MS and ICP-OES. A PCA was performed for each site and for annual and event datasets. Results show that a large number of element concentrations strongly correlate with DOC concentrations at the bog site. Even elements like Ca and Mg, which are known to have a low affinity to DOC. Congruently, the first principal component integrates the DOC pattern (element loadings > 0.8: Ca, Fe, Mg, Mn, Zn, As, Sr, Cd, DOC) and explained about 35 % of total variance and even 50 % during rain events (loadings > 0.8: Al, Ca, Fe, Mg, Mn, Zn, Li, Co, As, Sr, Cd, Pb, DOC). The study cannot verify that all correlating elements bind to DOC. It is likely that also a common mobilization pattern in the upper peat layer by plant decomposition causes the same response to changes in hydrologic pathways. Additionally, a low mineral content and an enrichment of elements like Fe and Mn in the upper peat layers due to prevailing redox conditions might play a major role in a bog environment. At the peaty riparian zone only Ca, Fe, and Sr strongly correlated with DOC over the annual record. The PCA of the annual record display no clear DOC component here, but indicates that DOC is influenced by Component one (element loadings > 0.8: Ca, Mg, Zn, Co, Sr) and two (Al, V, La, Pb, U) suggesting different DOC sources in the peaty riparian zone. A large number of elements correlate with DOC during rain event sampling at the riparian zone. In contrast to the bog site the event-based riparian zone PCA distinguished a clear discharge related component with mineral, groundwater related elements (K, Rb, In, Cs, NO3- and SO42-). Pattern of the mineral and DOC components prove that during base flow discharge is generated in a shallow groundwater layer and successively increases upward to the organic-rich upper soil layer with increasing discharge. Contrarily, bog element pattern confirm a dominating surface-near discharge, due to high hydraulic conductivities.

Thrust-ridge paleodepositional model for the Upper Freeport coal bed and associated clastic facies, Upper Potomac coal field, Appalachian Basin, U.S.A.

USGS Publications Warehouse

Belt, Edward S.; Lyons, P.C.

1990-01-01

Two differential depositional sequences are recognized within a 37-m-thick lowermost section of the Conemaugh Group of Late Pennsylvanian (Westphalian D) age in the southern part of the Upper Potomac coal field (panhandle of Maryland and adjacent West Virginia). The first sequence is dominated by the Upper Freeport coal bed and zone (UF); the UF consists of a complex of interfingered thick coal beds and mudrocks. The UF underlies the entire 500 km2 study area (approximately 40 km in a NE-SW direction). The second sequence is dominated by medium- to coarse-grained sandstone and pebbly sandstone. They were deposited in channel belts that cut into and interfingered laterally with mudrock and fine- to medium-grained sandstone facies of floodbasin and crevasse-lobe origin. Thin lenticular coals occur in the second sequence. Nowhere in the study area does coarse-grained sandstone similar to the sandstone of the channel belts of the second sequence occur within the UF. However, 20 km north of the study area, coarse channel belts are found that are apparently synchronous with the UF (Lyons et al., 1984). The southeastern margin of the study are is bounded by the Allegheny Front. Between it and the North Mountain thrust (75 km to the southeast), lie at least eight other thrusts of unknown extent (Wilson, 1887). All these thrusts are oriented northwest; Devonian and older strata are exposed at the surface between the Allegheny Front and the North Mountain thrust. A blind-thrust ridge model is proposed to explain the relation of the two markedly depositional sequences to the thrusts that lie to the southeast of the Upper Potomac coal field. This model indicates that thrust ridges diverted coarse clastics from entering the swamp during a period when the thick Upper Freeport peat accumulated. Anticlinal thrust ridges and associated depressions are envisioned to have developed parallel to the Appalachian orogen during Middle and early Late Pennsylvanian time. A blind thrust developed from one of the outboard ridges, and it was thrust farther outboard ahead of the main body of the orogen. Sediment derived from the orogen was diverted into a sediment trap inboard of the ridge (Fig. 1). The ridge prevented sediment from entering the main peat-forming swamp. Sediment shed from the orogen accumulated in the sediment trap was carried out of the ends of the trap by steams that occupied the shear zone at the ends of the blind-thrust ridge (Fig. 1). Remnants of blind-thrust ridges occurs in the Sequatchie Valley thrust and the Pine Mountain thrust of the southern Appalachians. The extent, parallel to the orogen, of the thick areally extensive UF coal is related to the length of the blind-thrust ridge that, in turn, controlled the spacing of the river-derived coarse clastics that entered the main basin from the east. Further tectonism caused the thrust plane to emerge to the surface of the blind-thrust ridge. Peat accumulation was then terminated by the rapid erosion of the blind-thrust ridge and by the release of trapped sediment behind it. The peat was buried by sediments from streams from closely spaced channel belts] with intervening floodbasins. The model was implications for widespread peat (coal) deposits that developed in tropical regions, a few hundred kilometers inland from the sea during Pennsylvanian time (Belt and Lyons, 1989). ?? 1990.

Changes in vegetation, peat properties and peat accumulation in Swedish peatlands as revealed by archive data.

NASA Astrophysics Data System (ADS)

Schoning, Kristian; Sohlenius, Gustav

2016-04-01

In this investigation we have studied patterns in peat accumulation and changes in mire status since the early 1900s for two areas in Sweden. In the early 1900s the Geological Survey of Sweden collected a vast amount of peat and peatland data, including information on vegetation and land-use. We have used this archive data to evaluate changes in mire vegetation, mire wetness and surface peat properties, rates of peat accumulation, succession in young wetlands and the effects of cultivation on peatlands. In total 156 mires in an uplift area of eastern middle Sweden were included in the data-set, including both pristine mires and peatlands used for agricultural purposes. In this area new peatlands have continuously been formed during the past 7 000 years making it possible to evaluate changes in peat accumulation over time. The other study area is situated in the south Swedish Uplands where we have revisited some larger bogs. The results from our investigation show that many of the peatlands have underwent major changes since the early 1900s. In most of the small peatlands we have found important changes in vegetation where mire vegetation has been replaced by nutrient demanding and/or dry species flora while the tree stand on large mires in south Sweden have increased. In some mires humification has increased in the uppermost peat-layers and the mire surface have become drier compared to the early 1900s. In eastern middle Sweden there are indications that the peat accumulation is lower 0,5 mm/year in older peatlands compared with younger ones 1,2 mm/year, although the mire vegetation in the older peatlands is dominated by sphagnum. The peat depth of the cultivated mires in this area shows a mean decrease of 40 cm since the early 1900s.

First results of the palaeogeographical research in Limyra and its environs (SW-Turkey)

NASA Astrophysics Data System (ADS)

Stock, Friederieke; Uncu, Levent; Seyer, Martin; Brückner, Helmut

2017-04-01

Geoarchaeological research in and around ancient cities of Asia Minor is an important tool for reconstructing the palaeogeography of their environs. An intensive geoarchaeological research project has started 2015 in the framework of a cooperation between the Austrian Archaeological Institute (ÖAI) and the University of Cologne (Brückner et al., 2016). 21 sediment cores were carried out in the ancient city of Limyra and its environs since 2015 and analysed with a multi-proxy approach (geochemical, sedimentological and microfaunal methods). The main goals of the project are to reconstruct (i) the environment, especially during the Classical to Late Roman periods; (ii) the geohydrological situation; (iii) the thickness of the settlement layers; (iv) the maximum extension of the former lake; to reveal (vi) the earthquake chronology and (vii) the spatio-temporal shifts in the coastline. First results show that the middle and eastern part of the city had been built on top of former lake sediments. Peat layers (so-called "floating peats") are intercalated and represent the starting siltation process. The reactivated lake phases, expressed in the rapid transitions from peat to lake strata, may be explained by earthquakes with co-seismic subsidence. Then follow fluvial sands with a fining-upward sequence (gravel at the base, overlain sands and alluvia). The strata provide information about shifting river channels. Anthropogenic layers form the top part of the core; they partly consolidated a swampy environment (core-filling limestone layers). In drill cores located between the eastern and the western city, pebbles and edged stones with artifacts follow on top of lake sediments and sands (littoral). The stones seem to have been intentionally deposited; people may have settled at the lake shore. The peat layer on top may represent the changing hydrology and co-seismic subsidence. The drill cores outside the city area confirm the sediment sequence: on top of limnic follow by a fluvial facies (fining-upward sequence, sands, alluvium). Lim 20, carried out close to the present coast reveals homogenous sands overlying the fluvial ones. The stratigraphy most likely represents the uppermost layers of a beach barrier which is overlain by dunes. Thus, the explanation that the origin of the lake was a lagoon is the most probable one.

From carbon sink to carbon source: extensive peat oxidation in insular Southeast Asia since 1990

NASA Astrophysics Data System (ADS)

Miettinen, Jukka; Hooijer, Aljosja; Vernimmen, Ronald; Liew, Soo Chin; Page, Susan E.

2017-02-01

Tropical peatlands of the western part of insular Southeast Asia have experienced extensive land cover changes since 1990. Typically involving drainage, these land cover changes have resulted in increased peat oxidation in the upper peat profile. In this paper we provide current (2015) and cumulative carbon emissions estimates since 1990 from peat oxidation in Peninsular Malaysia, Sumatra and Borneo, utilizing newly published peatland land cover information and the recently agreed Intergovernmental Panel on Climate Change (IPCC) peat oxidation emission values for tropical peatland areas. Our results highlight the change of one of the Earth’s most efficient long-term carbon sinks to a short-term emission source, with cumulative carbon emissions since 1990 estimated to have been in the order of 2.5 Gt C. Current (2015) levels of emissions are estimated at around 146 Mt C yr-1, with a range of 132-159 Mt C yr-1 depending on the selection of emissions factors for different land cover types. 44% (or 64 Mt C yr-1) of the emissions come from industrial plantations (mainly oil palm and Acacia pulpwood), followed by 34% (49 Mt C yr-1) of emissions from small-holder areas. Thus, altogether 78% of current peat oxidation emissions come from managed land cover types. Although based on the latest information, these estimates may still include considerable, yet currently unquantifiable, uncertainties (e.g. due to uncertainties in the extent of peatlands and drainage networks) which need to be focused on in future research. In comparison, fire induced carbon dioxide emissions over the past ten years for the entire equatorial Southeast Asia region have been estimated to average 122 Mt C yr-1 (www.globalfiredata.org/_index.html). The results emphasise that whilst reducing emissions from peat fires is important, urgent efforts are also needed to mitigate the constantly high level of emissions arising from peat drainage, regardless of fire occurrence.

Features of seasonal temperature variations in peat soils of oligotrophic bogs in south taiga of Western Siberia

NASA Astrophysics Data System (ADS)

Kiselev, M. V.; Dyukarev, E. A.; Voropay, N. N.

2018-03-01

The work presents the results of the study of the peculiarities of the temperature regime in the five basic ecosystems of oligotrophic bogs in the south taiga zone of Western Siberia in 2011-2016. The soil temperature regime was studied using the atmospheric-soil measuring complex at different depths from surface down to 240 cm. All sites were divided into two groups according to the bog water level: flooded sites (hollow and open fen) and drained sites (ridge, tall and low ryam). The waterlogged sites are better warmed in the summer period and slowly freeze in the winter period. The analysis of the annual cycle of temperature showed that the maximum surface temperature is in July. The minimum temperature on the surface is observed in February or January. The greatest temperature gradient was recorded in the upper 2 cm layer. The gradient at the open fen was -2 °C/cm in February and 1.1 °C/cm in October. The peak of formation of the seasonally frozen layer occurs at the end of autumn or in the beginning of winter. The degradation of the seasonally frozen layer was observed both from top and bottom, but the degradation rate from the top is faster.

Seven hundred years of peat formation recorded throughout a deep floating mire profile from Central Italy

NASA Astrophysics Data System (ADS)

Lobianco, Daniela; D'Orazio, Valeria; Miano, Teodoro; Zaccone, Claudio

2016-04-01

Floating mires are defined by the occurrence of emergent vegetation rooted in highly organic buoyant mats that rise and fall with changes in water level. Islands floating and moving on a lake naturally were already described by Pliny the Elder in his Naturalis historia almost two millennia ago. Actually, he devoted a whole chapter of Naturalis historia to "Of Islands Ever Floating and Swimming", reporting how certain isles were always waving and never stood still. The status of "flotant" has been defined transitory; in fact, these small isles often disappear, in most of the cases because of a transition from floating island to firm land during decades is likely to happen. That is why most of the floating islands described by Pliny the Elder (e.g., Lacus Fundanus, Lacus Cutiliensis, Lacus Mutinensis, Lacus Statoniensis, Lacus Tarquiniensis, Lydia Calaminae, Lacus Vadimonis) do not exist anymore. In the present study, peat formation and organic matter evolution were investigated in order to understand how these peculiar environments form, and how stable actually they are. In fact, it is hoped that peat-forming floating mires could provide an exceptional tool for environmental studies, since much of their evolution, as well as the changes of the surrounding areas, is recorded in their peat deposits. A complete, 4-m deep peat core was collected in July 2012 from the floating island of Posta Fibreno, a relic mire in the Central Italy. This floating island has a diameter of ca. 30 m, a submerged thickness of about 3 m, and the vegetation is organized in concentric belts, from the Carex paniculata palisade to the Sphagnum centre. Here, some of the southernmost Italian populations of Sphagnum palustre occur. The 14C age dating of organic sediments isolated from the sample at 385 cm of depth revealed that the island formed ca. 700 yrs ago (620±30 yr BP). The top 100 cm, consisting almost exclusively of Sphagnum mosses, show a very low bulk density (avg., 0.03±0.01 g cm-3), an ash content ranging from 0.8 and 7.4%, an average gravimetric water content of 26.6±7.7 gwater gdrypeat-1, and a pH generally increasing with depth (from 4.1 to 7.2). The C content along the profile ranged between 35 and 47% (avg., 41±4%), whereas the N between 0.3 and 1.1% (avg., 0.5±0.1%). Main atomic ratios (C/N, H/C and O/C) and FT-IR spectra seem to confirm what found during the visual inspection of the core, i.e., Sphagnum material so well preserved that it is hard to classify it as "peat". In fact, the 14C age dating suggests that the first 110 cm of Sphagnum material accumulated in ca. 55 yrs, thus resulting in an average growing rate of 2 cm yr-1. The remaining 300 cm (from 100 to 400 cm of depth), i.e., the submerged part of the island, consist of peat showing completely different botanical composition (reed-fen peat and silty peat rich in reeds) and physical and chemical properties. In particular, both bulk density (avg., 0.09±0.05 g cm-3) and ash content increase, reaching their maximum at 300-325 cm of depth (0.27 g cm-3 and 17%, respectively), whereas the average gravimetric water content significantly decreases (17.4±9.0 gwater gdrypeat-1). The pH ranges from 6.6 and 7.4. Both C and N along this section of the profile show higher average contents (44±3 and 1.3±0.6%, respectively) compared to those recorded in the upper 100 cm layer; furthermore, the decrease with depth of C/N, H/C and O/C atomic ratios, as well as main absorption bands of FT-IR spectra, clearly indicate the occurrence of an organic matter highly humified. The estimated accumulation rate for the bottom 300 cm of the island is 0.5 cm yr-1. At the best of our knowledge, this work represents the first characterization of a (4 m) deep floating mire profile. At Posta Fibreno, the deep water layer below the base of the island (7 m) and the movement on the water surface probably avoided the transition from floating island to firm land, thus allowing this island to float during the last centuries. The Authors thank the Municipality of Posta Fibreno (FR), Managing Authority of the Regional Natural Reserve of Lake Posta Fibreno, for allowing peat cores sampling.

Miocene and Pliocene lacustrine and fluvial sequences, Upper Ramparts and Canyon village, Porcupine river, east-central Alaska

USGS Publications Warehouse

Fouch, T.D.; Carter, L.D.; Kunk, Michael J.; Smith, C.A.S.; White, J.M.

1994-01-01

Cenozoic strata exposed along the Porcupine River between the Upper Ramparts and Canyon Village, Alaska, can be divided into five unconformity-bounded units (sequences) which are: lower and middle Miocene unit A, the white sandy fluvial sequence with peat beds; middle Miocene unit B, the basalt sequence-part B1 is basalt, and part B2 is organic-rich sedimentary beds; upper Miocene unit C, mudrock-dominated lake sequence; late Miocene or Pliocene to Pleistocene unit D, terrace gravels, detrital organic matter and associated sediments, and Holocene unit E, mixed sand and gravel-rich sediment and other sedimentary material including peat and eolian silt. The sequence (unit A) of lower and middle Miocene fluvial deposits formed in streams and on flood plains, just before the inception of local volanism. Fossil pollen from unit A suggests conifer-dominated regional forests and cool temperate climates. Peat beds and lake deposits from unit B contain pollen that indicates a warmer temperate climate coinciding with the middle Miocene thermal maximum. The lake deposits (unit C) downstream from the basalts accumulated in a small basin which resulted from a hydrologic system that was dammed in the late Miocene but breached soon thereafter. The lower part of the terrace gravels (unit D) expresses breaching of the dammed hydrologic system (of unit C). The Porcupine River became a major tributary of the Yukon River in late Pleistocene time when Laurentide ice blocked drainage from the Yukon interior basins causing meltwater to spill over the low divide separating it from the Porcupine River drainage initiating erosion and capture of the Yukon interior basins. ?? 1994.

Palaeoenvironmental reconstruction of Hüsamlar coal seam, SW Turkey

NASA Astrophysics Data System (ADS)

Büçkün, Zeynep; İnaner, Hülya; Oskay, Riza Görkem; Christanis, Kimon

2015-06-01

The Ören and Yatağan Basins in SW Turkey host several Miocene coal deposits currently under exploitation for power generation. The present study aims to provide insight into the palaeoenvironmental conditions, which controlled the formation of the Hüsamlar coal seam located in Ören Basin. The coal seam displays many sharp alternations of matrix lignite beds and inorganic, lacustrine sediment layers. The coal is a medium-to-high ash lignite (10.47-31.16 wt%, on dry basis) with high total sulphur content (up to 10 wt%, on dry, ash-free basis), which makes it prone to self-combustion. The maceral composition indicates that the peat-forming vegetation consisted of both arboreal and herbaceous plants, with the latter being predominant in the upper part of the seam. Mica and feldspars contribute to the low part of the seam; carbonates are dominant in the upper part, whereas quartz and pyrite are present along the entire coal profile. The sudden transitions of the telmatic to the lacustrine regime and reverse is attributed to tectonic movements that controlled water table levels in the palaeomire, which affected surface runoff and hence, clastic deposition.

Elucidating effects of atmospheric deposition and peat decomposition processes on mercury accumulation rates in a northern Minnesota peatland over last 10,000 cal years

NASA Astrophysics Data System (ADS)

Nater, E. A.; Furman, O.; Toner, B. M.; Sebestyen, S. D.; Tfaily, M. M.; Chanton, J.; Fissore, C.; McFarlane, K. J.; Hanson, P. J.; Iversen, C. M.; Kolka, R. K.

2014-12-01

Climate change has the potential to affect mercury (Hg), sulfur (S) and carbon (C) stores and cycling in northern peatland ecosystems (NPEs). SPRUCE (Spruce and Peatland Responses Under Climate and Environmental change) is an interdisciplinary study of the effects of elevated temperature and CO2 enrichment on NPEs. Peat cores (0-3.0 m) were collected from 16 large plots located on the S1 peatland (an ombrotrophic bog treed with Picea mariana and Larix laricina) in August, 2012 for baseline characterization before the experiment begins. Peat samples were analyzed at depth increments for total Hg, bulk density, humification indices, and elemental composition. Net Hg accumulation rates over the last 10,000 years were derived from Hg concentrations and peat accumulation rates based on peat depth chronology established using 14C and 13C dating of peat cores. Historic Hg deposition rates are being modeled from pre-industrial deposition rates in S1 scaled by regional lake sediment records. Effects of peatland processes and factors (hydrology, decomposition, redox chemistry, vegetative changes, microtopography) on the biogeochemistry of Hg, S, and other elements are being assessed by comparing observed elemental depth profiles with accumulation profiles predicted solely from atmospheric deposition. We are using principal component analyses and cluster analyses to elucidate relationships between humification indices, peat physical properties, and inorganic and organic geochemistry data to interpret the main processes controlling net Hg accumulation and elemental concentrations in surface and subsurface peat layers. These findings are critical to predicting how climate change will affect future accumulation of Hg as well as existing Hg stores in NPE, and for providing reference baselines for SPRUCE future investigations.

Lateral carbon fluxes and CO2 outgassing from a tropical peat-draining river

NASA Astrophysics Data System (ADS)

Müller, D.; Warneke, T.; Rixen, T.; Müller, M.; Jamahari, S.; Denis, N.; Mujahid, A.; Notholt, J.

2015-07-01

Tropical peatlands play an important role in the global carbon cycle due to their immense carbon storage capacity. However, pristine peat swamp forests are vanishing due to deforestation and peatland degradation, especially in Southeast Asia. CO2 emissions associated with this land use change might not only come from the peat soil directly, but also from peat-draining rivers. So far, though, this has been mere speculation, since there was no data from undisturbed reference sites. We present the first combined assessment of lateral organic carbon fluxes and CO2 outgassing from an undisturbed tropical peat-draining river. Two sampling campaigns were undertaken on the Maludam river in Sarawak, Malaysia. The river catchment is covered by protected peat swamp forest, offering a unique opportunity to study a peat-draining river in its natural state, without any influence from tributaries with different characteristics. The two campaigns yielded consistent results. Dissolved organic carbon (DOC) concentrations ranged between 3222 and 6218 μmol L-1 and accounted for more than 99 % of the total organic carbon (TOC). Radiocarbon dating revealed that the riverine DOC was of recent origin, suggesting that it derives from the top soil layers and surface runoff. We observed strong oxygen depletion, implying high rates of organic matter decomposition and consequently CO2 production. The measured median pCO2 was 7795 and 8400 μatm during the two campaigns, respectively. Overall, we found that only 26 ± 15 % of the carbon was exported by CO2 evasion, while the rest was exported by discharge. CO2 outgassing seemed to be moderated by the short water residence time. Since most Southeast Asian peatlands are located at the coast, this is probably an important limiting factor for CO2 outgassing from most of its peat-draining rivers.

Hybrid biosorbents for removal of pollutants and remediation

NASA Astrophysics Data System (ADS)

Burlakovs, Juris; Klavins, Maris; Robalds, Artis; Ansone, Linda

2014-05-01

For remediation of soils and purification of polluted waters, wastewaters, biosorbents might be considered as prospective groups of materials. Amongst them peat have a special role due to low cost, biodegradability, high number of functional groups, well developed surface area and combination of hydrophilic/hydrophobic structural elements. Peat as sorbent have good application potential for removal of trace metals, and we have demonstrated peat sorption capacities, sorption kinetics, thermodynamics in respect to metals with different valencies - Tl(I), Cu(II), Cr(III). However, peat sorption capacity in respect to nonmetallic (anionic species) elements is low. Also peat mechanical properties do not support application in large scale column processes thereby, to expand peat application sphere, the approach of biomass based hybrid sorbents has been elaborated. The concept "hybrid sorbent" in understanding of biosorbent means natural, biomass based modified material, covered with another sorbent material, thus combining properties of both such as sorbent functionalities, surface properties etc. As the "covering layer" both inorganic substances, mineral phases (iron oxohydroxides, oxyappatite) and organic polymers (using graft polymerization) were used. The obtained sorbents were characterised by their spectral properties, surface area and elemental composition. The obtained hybrid sorbents were tested for sorption of compounds in anionic speciation forms, for example of arsenic, antimony, tellurium and phosphorous compounds in comparison with weakly basic anionites. The highest sorption capacity was observed when peat sorbents modified with iron compounds were used. Sorption of different arsenic speciation forms onto iron-modified peat sorbents was investigated as a function of pH and temperature. It was established that sorption capacity increases with a rise in temperature as the calculation of sorption process thermodynamic parameters indicates the spontaneity of sorption process and its endothermic nature. The recycling options of obtained compounds after their saturation with metal or non-metallic species are suggested.

The use of Ground Penetrating Radar in coastal research, archeaological investigations, lake studies, peat layer measurments and applied research in Estonia

NASA Astrophysics Data System (ADS)

Vilumaa, Kadri; Tõnisson, Hannes; Orviku, Kaarel

2014-05-01

Ground Penetrating Radar (GPR) is mainly used for scientific research in coastal geology in the Institute of Ecology at Tallinn University. We currently use SIR-3000 radar with 100, 270 , 300 and 500 MHz antennae. Our main targets have been detecting the thickness of soil and sand layers and finding out the layers in coastal sediments which reflect extreme storm events. Our GPR studies in various settings have suggested that the internal structures of the ridge-dune complexes are dominated by numerous layers dipping in various directions. Such information helps us to reconstruct and understand prevailing processes during their formation (e.g. seaward dipping lamination in coastal ridge-dune complexes indicating cross-shore and wave-induced transport of the sediments). Currently, we are trying to elaborate methodology for distinguishing the differences between aeolian and wave transported sediments by using GPR. However, paludified landscapes (often covered by water), very rough surface (numerous bushes and soft surface), moderate micro topography has slowed this process significantly. Moreover, we have been able to use GPR during the winter period (applied on ice or snow) and compare the quality of our results with the measurements taken during the summer period. We have found that smooth surface (in winter) helps detecting very strong signal differences (border between different sediment types - sand, peat, silt, etc.) but reduces the quality of the signal to the level where the detection of sedimentation patterns within one material (e.g. tilted layers in sand) is difficult. We have carried out several other science-related studies using GPR. These studies include determining the thickness of peat layer in bogs (to calculate the volume of accumulated peat or to find most suitable locations for coring), measuring the thickness of mud and gyttja layer in lakes (to find most suitable locations for coring, reconstructing initial water level of the lake or calculating the volume of stored carbon in the lake). Additionally, we have done several archaeology-related research including the search of buried city walls and caves (Tallinn old town), buried Viking ship (Saaremaa Island) and several other archaeological objects. We have also done some applied studies including the search of underground power cables, heating pipes, melioration systems, ammunition warehouses (from World War II) and buried ammunition from the military training fields. Aknowledgement: The authors acknowledge COST for funding Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar', supporting part of this work.

Dissolved Organic Carbon in Marginal, Damaged Peatlands: Using 14C to Understand DOC Losses

NASA Astrophysics Data System (ADS)

Luscombe, D.; Grand-Clement, E.; Garnett, M.; Anderson, K.; Gatis, N.; Benaud, P.; Brazier, R.

2013-12-01

Peatlands are widely represented throughout the world and act as an important store of carbon, as well as providing society with a range of other ecosystem services, such as drinking water or the support of rare habitats. However, the combination of historical management practices, and the predicted impact of climate change means that they are now largely under threat. In the shallow peatlands of Exmoor National Park (South West UK), peat cutting and intensive drainage in the 19th and 20th century for agricultural reclamation have changed the hydrological behaviour of the peat. This damage has dried out the upper layers, causing oxidation, erosion and vegetation change. In addition, their location on the southernmost limit of peatlands geographical extent in northern Europe makes them particularly vulnerable to the predicted changes in rainfall and temperature. Recent modelling work has shown that such marginal peatlands may disappear as early as 2050. Restoration programs are currently in place, aiming to restore the hydrological functioning of the peat. However, current dissolved organic carbon (DOC) losses from damaged peatlands are especially of concern, because of the contribution of the aquatic pathways in the C flux, and because of the impact on water quality. DOC has been shown to originate from the drainage of highly-aged organic matter. In stream waters, DOC from low flow tends to contain a larger component of older C compared to that of high flow. Both the impact of extensive drainage on where DOC is originating from and the effect of peatland restoration on this process remain poorly understood. We used 14C dating of DOC from streams and pore water, as well as from damaged peat, in order to gain a better understanding of the process and origin of DOC loss in drained shallow peatlands. This will further help us understand the potential for peatland restoration. Work was carried out in a small intensively monitored catchment in Exmoor. Samples were taken in an area of shallow peat (ca. 20-30 cm depth) drained by a medium size ditch (50 x 50 cm). Samples of DOC from stream water were taken at low and high flow during 3 separate rain events in Winter- Spring 2013 using automatic pump samplers. Samples of DOC in pore water were taken 2 m away from the ditch at 5 and 15 cm depth on two occasions. Finally, matching bulk peat samples were collected at 5 and 15 cm depth. Intensive monitoring data also provides information on water table depth and level in streams. A neighbouring pristine peat area was used as a control, and DOC pore water and bulk peat soil samples were taken at 5, 15 and 45 cm depth on two occasions. Preliminary results show that DOC lost in streams at high flow contains a greater contribution of bomb-14C compared to that at low flow (107 and 101 % modern respectively). Stream water DOC at low flow had a 14C concentration lower than that in pore water at both 5 and 15 cm depth (105 and 102% modern, respectively), suggesting that low flow stream water DOC is predominantly older than that found in pore water at depth.

The xanthine oxidase activity in different of secondary transformed peat-moorsh soils

NASA Astrophysics Data System (ADS)

Styła, Katarzyna; Wojciech Szajdak, Lech

2010-05-01

The investigations were carried out on the transect of peatland 4.5 km long, located in the Agroecological Landscape Park host D. Chlapowski in Turew (40 km South-West of Poznań, West Polish Lowland). The sites investigation were located along Wyskoć ditch. The following material was taken from four chosen sites marked as Zbęchy, Bridge, Shelterbelt and Hirudo in two layers: acrotelm (0-50 cm) and catotelm (50-100 cm). The object of this study was to characterize the biochemical properties by the determination of the xanthine oxidase activity in two layers (acrotelm and catotelm) of the four different peat-moorsh soils used as meadow. The xanthine oxidase activity was determined spectrophotometrically by measuring uric acid formation at λmax=290 nm with xanthine as substrate. In peat-moorsh soil the highest activities of xanthine oxidasewas observed in the Shelterbelt and whereas the lowest - in Zbęchy, Bridge and Hirudo. Activities of this enzyme in peat-moorsh soil ranged from 5.96 to 19.51 μmol h-1g d.m soil. Increased activities of xanthine oxidase have been recorded on the depth 50-100 cm - catotelm (from 11.71 to 19.51 μmol h-1g d.m soil) in comparison with the depth 0-50 cm - acrotelm (from 5.96 to 14.64 μmol h-1g d.m soil). This work was supported by a grant No. N N305 3204 36 founded by Polish Ministry of Education.

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

NASA Astrophysics Data System (ADS)

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

2013-04-01

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

Hydro-thermal processes and thermal offsets of peat soils in the active layer in an alpine permafrost region, NE Qinghai-Tibet plateau

NASA Astrophysics Data System (ADS)

Wang, Qingfeng; Jin, Huijun; Zhang, Tingjun; Cao, Bin; Peng, Xiaoqing; Wang, Kang; Xiao, Xiongxin; Guo, Hong; Mu, Cuicui; Li, Lili

2017-09-01

Observation data of the hydrothermal processes in the active layer are vital for the verification of permafrost formation and evolution, eco-hydrology, ground-atmosphere interactions, and climate models at various time and spatial scales. Based on measurements of ground temperatures in boreholes, of temperatures and moisture contents of soils in the active layer, and of the mean annual air temperatures at the Qilian, Yeniugou and Tuole meteorological stations in the upper Heihe River Basin (UHRB) and the adjacent areas, a series of observations were made concerning changes in the lower limit of permafrost (LLP) and the related hydrothermal dynamics of soils in the active layer. Because of the thermal diode effect of peat soils, the LLP (at 3600 m) was lower on the northern slope of the Eboling Mountains at the eastern branch of the UHRB than that (at 3650-3700 m) on the alluvial plain at the western branch of the UHRB. The mean temperature of soils at depths of 5 to 77 cm in the active layer on peatlands was higher during periods with subzero temperatures and lower during periods with above-zero temperatures in the vicinity of the LLP on the northern slope of the Eboling Mountains than those at the LLP at the western branch of the UHRB. The thawing and downward freezing rates of soils in the active layer near the LLP on the northern slope of the Eboling Mountains were 0.2 and 1.6 times those found at the LLP at the western branch of the UHRB. From early May to late August, the soil water contents at the depths of 20 to 60 cm in the active layer near the LLP on the northern slope of the Eboling Mountains were significantly lower than those found at the LLP at the western branch of the UHRB. The annual ranges of soil temperatures (ARSTs), mean annual soil temperatures (MASTs) in the active layer on peatlands, and the mean annual ground temperature (MAGT) at a depth of 14 m of the underlying permafrost were all significantly lower near the LLP on the northern slope of the Eboling Mountains. Moreover, the thermophysical properties of peat soils and high moisture contents in the active layer on peatlands resulted in the lower soil temperatures in the active layer close to the LLP on the northern slope of the Eboling Mountains than those found at the LLP at the western branch of the UHRB in the warm season, especially at the deeper depths (20-77 cm). They also resulted in the smaller freezing index (FI) and thawing index (TI) and larger FI/TI ratios of soils at the depths of 5 to 77 cm in the active layer near the LLP on the northern slope of the Eboling Mountains. In short, peatlands have unique thermophysical properties for reducing heat absorption in the warm season and for limiting heat release in the cold season as well. However, the permafrost zone has shrunk by 10-20 km along the major highways at the western branch of the UHRB since 1985, and a medium-scale retrogressive slump has occurred on the peatlands on the northern slope of the Eboling Mountains in recent decades. The results can provide basic data for further studies of the hydrological functions of different landscapes in alpine permafrost regions. Such studies can also enable evaluations and forecasts the hydrological impacts of changing frozen ground in the UHRB and of other alpine mountain regions in West China.

Late-Holocene Environmental Reconstruction and Depositional History from a Taxodium Swamp near Lake Pontchartrain in Southern Louisiana

NASA Astrophysics Data System (ADS)

Ryu, J.; Bianchette, T. A.; Liu, K. B.; Yao, Q.; Maiti, K.

2017-12-01

The hydrological and environmental history of estuarine wetlands in Louisiana is not well-documented. To better understand the depositional processes in coastal wetlands, this study aims to reconstruct the environmental changes and document the occurrence of event deposits found in a bald cypress (Taxodium distichum) swamp approximately 800 m west of Lake Pontchartrain, a site susceptible to wind-generated storm surges as well as inundation from other fluvial and lacustrine processes. 210Pb analysis of a 59 cm sediment core (WMA-1) suggests that it has a sedimentation rate of 0.39 cm/year, consistent with the detection of a 137Cs peak at 17 cm from the core top. Results of sedimentological, geochemical, and palynological analyses reveal that the core contains two distinct sediment facies: an organic-rich dark brown peat unit from 0 to 29 cm containing low concentrations of terrestrial elements (e.g., Ti, Fe, and K), and a clay unit from 30 to 59 cm with elevated concentrations of most elements. Two thin clay layers, at 3-5 cm and 14-19 cm, embedded in the upper peat section are probably attributed to two recent storm events, Hurricane Isaac (2012) and Hurricane Gustav (2008), because both hurricanes caused heavy rain and significant storm-surge flooding at the study site. The pollen assemblage in the clay section is dominated by TCT (mainly Taxodium), but it is replaced by Salix and wetland herbaceous taxa in the overlying peat section. The multi-proxy data suggest that a cypress swamp has been present at the site for at least several hundred years but Taxodium was being replaced by willow (Salix) and other bottomland hardwood trees and wetland herbs as the water level dropped. Human activities may have been an important factor causing the hydrological and ecological changes at the site during the past century.

Production flush of Agaricus blazei on Brazilian casing layers

PubMed Central

Colauto, Nelson Barros; da Silveira, Adriano Reis; da Eira, Augusto Ferreira; Linde, Giani Andrea

2011-01-01

This study aimed to verify the biological efficiency and production flushes of Agaricus blazei strains on different casing layers during 90 cultivation days. Four casing layers were used: mixture of subsoil and charcoal (VCS), lime schist (LSC), São Paulo peat (SPP) and Santa Catarina peat (SCP); and two genetically distant A. blazei strains. The fungus was grown in composted substratum and, after total colonization, a pasteurized casing layer was added over the substratum, and fructification was induced. Mushrooms were picked up daily when the basidiocarp veil was stretched, but before the lamella were exposed. The biological efficiency (BE) was determined by the fresh basidiocarp mass divided by the substratum dry mass, expressed in percentage. The production flushes were also determined over time production. The BE and production flushes during 90 days were affected by the strains as well as by the casing layers. The ABL26 and LSC produced the best BE of 60.4%. Although VCS is the most used casing layer in Brazil, it is inferior to other casing layers, for all strains, throughout cultivation time. The strain, not the casing layer, is responsible for eventual variations of the average mushroom mass. In average, circa 50% of the mushroom production occurs around the first month, 30% in the second month, and 20% in third month. The casing layer water management depends on the casing layer type and the strain. Production flush responds better to water reposition, mainly with ABL26, and better porosity to LSC and SCP casing layers. PMID:24031673

Technogenic magnetic particles in soils as evidence of historical mining and smelting activity: A case of the Brynica River Valley, Poland.

PubMed

Magiera, Tadeusz; Mendakiewicz, Maria; Szuszkiewicz, Marcin; Jabłońska, Mariola; Chróst, Leszek

2016-10-01

In the area of Brynica River basin (Upper Silesia, southern Poland) the exploitation and smelting of iron, silver and lead ores was historically documented since early Middle Ages. First investigations showed that metallurgy industry had a large impact from 9th century (AD) until the Second World War. The aim of the study was to use magnetic prospection to detect traces of past mining and ore smelting in Brynica River Valley located in Upper Silesia (southern Poland). The field screening was performed by measurement magnetic susceptibility (κ) on surface and in vertical profiles and was supported locally by gradiometric measurements. Vertical distribution of magnetic susceptibility values was closely associated with the type of soil use. Historical technogenic magnetic particles resulting from exploitation, processing, and smelting of iron, silver, and lead ores were accumulated in the soil layer at the depth 10 to 25cm. They were represented by sharp-edged particles of slag, coke, as well as various mineralogical forms of iron minerals and aggregates composed of carbon particles, aluminosilicate glass, and single particles of metallic iron. The additional geochemical study in adjacent peat bog supported by radiocarbon dating was also performed. The application of integrated geochemical-magnetic methods to reconstruct the historical accumulation of pollutants in the studied peat bog was effective. The magnetic peak, which was pointed out by magnetic analyses, is consistent with the presence of charcoal and pollution from heavy metals, such as Ag, Cd, Cu, Fe, Pb, or Sn. The results of this work will be helpful for the further study of human's impact on the environment related to the historical and even pre-historical ore exploitation and smelting and also used for better targeting the archeological excavations on such areas. Copyright © 2016 Elsevier B.V. All rights reserved.

Peat hybrid sorbents for treatment of wastewaters and remediation of polluted environment

NASA Astrophysics Data System (ADS)

Klavins, Maris; Burlakovs, Juris; Robalds, Artis; Ansone-Bertina, Linda

2015-04-01

For remediation of soils and purification of polluted waters, wastewaters, sorbents might be considered as an prospective group of materials and amongst them peat have a special role due to low cost, biodegradability, high number of functional groups, well developed surface area and combination of hydrophilic/hydrophobic structural elements. Peat as sorbent have good application potential for removal of trace metals, and we have demonstrated peat sorption capacities, sorption kinetics, thermodynamics in respect to metals with different valencies - Tl(I), Cu(II), Cr(III). However peat sorption capacity in respect to nonmetallic (anionic species) elements is low. Also peat mechanical properties do not support application in large scale column processes. To expand peat application possibilities the approach of biomass based hybrid sorbents has been elaborated. The concept "hybrid sorbent" in our understanding means natural, biomass based sorbent modified, covered with another sorbent material, thus combining two types of sorbent properties, sorbent functionalities, surface properties etc. As the "covering layer" both inorganic substances, mineral phases (iron oxohydroxides, oxyapatite) both organic polymers (using graft polymerization) were used. The obtained sorbents were characterised by their spectral properties, surface area, elemental composition. The obtained hybrid sorbents were tested for sorption of compounds in anionic speciation forms, for example of arsenic, antimony, tellurium and phosphorous compounds in comparison with weakly basic anionites. The highest sorption capacity was observed when peat sorbents modified with iron compounds were used. Sorption of different arsenic speciation forms onto iron-modified peat sorbents was investigated as a function of pH and temperature. It was established that sorption capacity increases with a rise in temperature, and the calculation of sorption process thermodynamic parameters indicates the spontaneity of sorption process and its endothermic nature. The recycling options of obtained compounds after their saturation with metal or non-metallic species are suggested. Acknowledgement: Support from a project 2014/0009/1DP/1.1.1.2.0/13/APIA/VIAA/044

Stratigraphic response of salt marshes to slow rates of sea-level change

NASA Astrophysics Data System (ADS)

Daly, J.; Bell, T.

2006-12-01

Conventional models of salt-marsh development show an idealized spatial relationship between salt-marsh floral and foraminiferal zones, where the landward margin of the marsh gradually migrates inland in response to sea-level rise. This model predicts that transgression will result in persistent and possibly expanded salt marshes at the surface, depending on a variety of factors including sediment supply, hydrologic conditions, tidal range, and rate of sea-level rise. However, in areas with abundant sediment supply and slow rates of sea- level rise, the extent of back-barrier salt marshes may decline over time as the barrier-spits mature. Sea level around the northeast coast of Newfoundland is rising at a very slow rate during the late Holocene (<0.5 mm/yr). Sandy barrier-spits and tombolos are common coastal features, but salt marshes are rare. The generalized stratigraphy of dutch cores collected in back-barrier settings in this region is a surface layer of sphagnum peat with abundant woody roots, underlain by sedge-dominated peat that transitions gradually to a thin layer of Juncus sp. peat with agglutinated foraminifera, dominantly Jadammina macrescens and Balticammina pseudomacrescens. These basal peats are interpreted as salt-marsh peats, characterized by the presence of foraminifera that are absent in overlying peat units. This sequence indicates that salt marshes developed in back-barrier environments during the initial stages of barrier progradation, then gradually transitioned to environments increasingly dominated by freshwater flora. These transitions are interpreted to reflect the progradation of the spit, decreased tidal exchange in the back-barrier, and increased influence of freshwater streams discharging into the back-barrier setting. Decreased marine influence on the back-barrier environment leads to a floral and faunal shift associated with a regressive stratigraphy in an area experiencing sea-level rise. For studies of Holocene sea-level change requiring salt-marsh stratigraphic records, it is necessary to account for changing micro-environments to locate sites appropriate for study; salt marshes may play an important role in defining the record, but may not exist at the surface to guide investigation.

Monitoring the effects of manure policy in the Peat region, Netherlands

NASA Astrophysics Data System (ADS)

Hooijboer, Arno; Buis, Eke; Fraters, Dico; Boumans, Leo; Lukacs, Saskia; Vrijhoef, Astrid

2014-05-01

Total N concentrations in farm ditches in the Peat region of the Netherlands are on the average twice as high as the Good Ecological Potential value of the Water Framework Directive. Since ditches are connected to regional surface water, they may contribute to eutrophication. The minerals policy aims to improve the water quality. In the Netherlands, the effectiveness of the minerals policy on water quality is evaluated with data from the National Minerals Policy Monitoring Programme (LMM). This regards farm data on the quality of water leaching from the root zone and on farm practices. The soil balance nitrogen surpluses decreased between 1996 and 2003 on dairy farms in the Peat region. However, no effect on root zone leaching was found. This study aims to show how monitoring in the Peat region can be improved in order to link water quality to agricultural practice. Contrary to the other Dutch regions, nitrate concentrations in root zone leaching on farms in the Peat region are often very low (90% of the farms below 25 mg/l) due to the reduction of nitrate (denitrification). The main nitrogen (N) components in the peat region waters are ammonium and organic N. Total N is therefore a better measure for N concentrations in the Peat region. The ammonium concentration in groundwater in Dutch peat soils increases with depth. It is assumed that the deeper ammonia-rich water is older and relates to anaerobic peat decomposition instead of agricultural practice. Recent infiltrated low-ammonium water, lies like a thin freshwater lens on the older water. In the Peat region, root zone leaching is monitored by taking samples from the upper meter of groundwater. Unintended, often both lens water and older water are sampled and this distorts the relation between agricultural practice and water quality. In the Peat region, the N surplus is transported with the precipitation surplus to ditches. The relation between the N surplus and the total N in ditch water is therefore better than between N surplus and total N in root zone leaching. The precipitation surplus flows to ditches directly or via open field drains. However, the ditches may be fed partly with older water (seepage of groundwater). In the open field drain only recent water will occur. We expect that monitoring the water quality of the open field drains may even better reflect changes in agricultural practices. These data may also improve the understanding of contribution of agricultural nitrogen and natural nitrogen, necessary to develop measures to decrease the total-N concentration in ditch water.

The hydrology of northern peatlands as affected by biogenic gas: Current developments and research needs

USGS Publications Warehouse

Rosenberry, D.O.; Glaser, P.H.; Siegel, D.I.

2006-01-01

Recent research indicates that accumulation and release of biogenic gas from northern peatlands may substantially affect future climate. Sudden release of free-phase gas bubbles into the atmosphere may preclude the conversion of methane to carbon dioxide in the uppermost oxic layer of the peat, resulting in greater contribution of methane to the atmosphere than is currently estimated. The hydrology of these peatlands also affects and is affected by this process, especially when gas is released suddenly and episodically. Indirect hydrological evidence indicates that ebullitive gas releases are relatively frequent in some peatlands and time-averaged rates may be significantly greater than diffusive releases. Estimates of free-phase gas contained in peat have ranged from 0 to nearly 20% of the peat volume. Abrupt changes in the volume of gas may alter hydraulic gradients and movement of water and solutes in peat, which in turn could alter composition and fluxes of the gas. Peat surfaces also move vertically and horizontally in response to accumulation and release of free-phase gas. Future research should address the distribution, temporal variability, and relative significance of ebullition in peatlands and the consequent hydrological responses to these gas-emission events. Copyright ?? 2006 John Wiley & Sons, Ltd.

[Distribution of soil organic carbon storage and carbon density in Gahai Wetland ecosystem].

PubMed

Ma, Wei-Wei; Wang, Hui; Huang, Rong; Li, Jun-Zhen; Li, De-Yu

2014-03-01

The profile distribution and accumulation characteristics of organic carbon of four typical marshes (herbaceous peat, marsh wetland, mountain wetland, subalpine meadow) were studied in Gahai Wetlands of Gannan in July 2011. The results showed that the soil bulk densities of the four typical marshes ranged from 0.22 to 1.29 g x cm(-3). The content of soil organic carbon in the herbaceous peat was higher than in other types, with its average content of organic carbon (286. 80 g x kg(-1)) being about 2.91, 4.99, 7.31 times as much as that of the marsh wetland, mountain wetland and subalpine meadow, respectively. The average organic carbon densities were in order of herbaceous peat > subalpine meadow > marsh wetland > mountain wetland, with the highest in the 0-10 cm layer. The change of organic carbon density along the soil profile was basically in accordance with the organic carbon content in the four typical marshes, but fluctuated with soil depth. There were obviously two carbon storage layers (0-10 and 20-40 cm, respectively) in the four typical marshes. The amounts of organic carbon stored in the 0-60 cm layer of the four typical marshes were 369.46, 278.83, 276.16, 292.23 t x hm(-2), respectively. The total amount of organic carbon stored in the 0-60 cm of the four typical marshes was about 9.50 x 10(6) t.

Heterogeneity of carbon loss and its temperature sensitivity in East-European subarctic tundra soils.

PubMed

Diáková, Kateřina; Čapek, Petr; Kohoutová, Iva; Mpamah, Promise A; Bárta, Jiří; Biasi, Christina; Martikainen, Pertti J; Šantrůčková, Hana

2016-09-01

Arctic peatlands store large stocks of organic carbon which are vulnerable to the climate change but their fate is uncertain. There is increasing evidence that a part of it will be lost as a result of faster microbial mineralization. We studied the vulnerability of 3500-5900 years old bare peat uplifted from permafrost layers by cryogenic processes to the surface of an arctic peat plateau. We aimed to find biotic and abiotic drivers of CLOSS from old peat and compare them with those of adjacent, young vegetated soils of the peat plateau and mineral tundra. The soils were incubated in laboratory at three temperatures (4°C, 12°C and 20°C) and two oxygen levels (aerobic, anaerobic). CLOSS was monitored and soil parameters (organic carbon quality, nutrient availability, microbial activity, biomass and stoichiometry, and extracellular oxidative and hydrolytic enzyme pools) were determined. We found that CLOSS from the old peat was constrained by low microbial biomass representing only 0.22% of organic carbon. CLOSS was only slightly reduced by the absence of oxygen and exponentially increased with temperature, showing the same temperature sensitivity under both aerobic and anaerobic conditions. We conclude that carbon in the old bare peat is stabilized by a combination of physical, chemical and biological controls including soil compaction, organic carbon quality, low microbial biomass and the absence of plants. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Investigating carbon dynamics in Siberian peat bogs using molecular-level analyses

NASA Astrophysics Data System (ADS)

Kaiser, K.; Benner, R. H.

2013-12-01

Total hydrolysable carbohydrates, and lignin and cutin acid compounds were analyzed in peat cores collected 56.8 N (SIB04), 58.4 N (SIB06), 63.8 N (G137) and 66.5 N (E113) in the Western Siberian Lowland to investigate vegetation, chemical compositions and the stage of decomposition. Sphagnum mosses dominated peatland vegetation in all four cores. High-resolution molecular analyses revealed rapid vegetation changes on timescales of 50-200 years in the southern cores Sib4 and Sib6. Syringyl and vanillyl (S/V) ratios and cutin acids indicated these vegetation changes were due to varying inputs of angiosperm and gymnosperm and root material. In the G137 and E113 cores lichens briefly replaced sphagnum mosses and vascular plants. Molecular decomposition indicators used in this study tracked the decomposition of different organic constituents of peat organic matter. The carbohydrate decomposition index was sensitive to the polysaccharide component of all peat-forming plants, whereas acid/aldehyde ratios of S and V phenols (Ac/AlS,V) followed the lignin component of vascular plants. Low carbohydrate decomposition indices in peat layers corresponded well with elevated (Ad/Al)S,V ratios. This suggested both classes of biochemicals were simultaneously decomposed, and decomposition processes were associated with extensive total mass loss in these ombrotrophic systems. Selective decomposition or transformation of lignin was observed in the permafrost-influenced northern cores G137 and E113. Both cores exhibited the highest (Ad/Al)S,V ratios, almost four-fold higher than measured in peat-forming plants. The extent of decomposition in the four peat cores did not uniformly increase with age, but showed episodic extensive decomposition events. Variable decomposition events independent of climatic conditions and vegetation shifts highlight the complexity of peatland dynamics.

Substitution of peat, fertiliser and manure by compost in hobby gardening: user surveys and case studies.

PubMed

Andersen, Jacob K; Christensen, Thomas H; Scheutz, Charlotte

2010-12-01

Four user surveys were performed at recycle centres (RCs) in the Municipalities of Aarhus and Copenhagen, Denmark, to get general information on compost use and to examine the substitution of peat, fertiliser and manure by compost in hobby gardening. The average driving distance between the users' households and the RCs was found to be 4.3 km and the average amount of compost picked up was estimated at 800 kg per compost user per year. The application layer of the compost varied (between 1 and 50 cm) depending on the type of use. The estimated substitution (given as a fraction of the compost users that substitute peat, fertiliser and manure with compost) was 22% for peat, 12% for fertiliser and 7% for manure (41% in total) from the survey in Aarhus (n=74). The estimate from the survey in Copenhagen (n=1832) was 19% for peat, 24% for fertiliser and 15% for manure (58% in total). This is the first time, to the authors' knowledge, that the substitution of peat, fertiliser and manure with compost has been assessed for application in hobby gardening. Six case studies were performed as home visits in addition to the Aarhus surveys. From the user surveys and the case studies it was obvious that the total substitution of peat, fertiliser and manure was not 100%, as is often assumed when assigning environmental credits to compost. It was more likely around 50% and thus there is great potential for improvement. It was indicated that compost was used for a lot of purposes in hobby gardening. Apart from substitution of peat, fertiliser and manure, compost was used to improve soil quality and as a filling material (as a substitute for soil). Benefits from these types of application are, however, difficult to assess and thereby quantify. Copyright © 2010 Elsevier Ltd. All rights reserved.

Lateral carbon fluxes and CO2 outgassing from a tropical peat-draining river

NASA Astrophysics Data System (ADS)

Müller, D.; Warneke, T.; Rixen, T.; Müller, M.; Jamahari, S.; Denis, N.; Mujahid, A.; Notholt, J.

2015-10-01

Tropical peatlands play an important role in the global carbon cycle due to their immense carbon storage capacity. However, pristine peat swamp forests are vanishing due to deforestation and peatland degradation, especially in Southeast Asia. CO2 emissions associated with this land use change might not only come from the peat soil directly but also from peat-draining rivers. So far, though, this has been mere speculation, since there has been no data from undisturbed reference sites. We present the first combined assessment of lateral organic carbon fluxes and CO2 outgassing from an undisturbed tropical peat-draining river. Two sampling campaigns were undertaken on the Maludam River in Sarawak, Malaysia. The river catchment is covered by protected peat swamp forest, offering a unique opportunity to study a peat-draining river in its natural state, without any influence from tributaries with different characteristics. The two campaigns yielded consistent results. Dissolved organic carbon (DOC) concentrations ranged between 3222 and 6218 μmol L-1 and accounted for more than 99 % of the total organic carbon (TOC). Radiocarbon dating revealed that the riverine DOC was of recent origin, suggesting that it derives from the top soil layers and surface runoff. We observed strong oxygen depletion, implying high rates of organic matter decomposition and consequently CO2 production. The measured median pCO2 was 7795 and 8400 μatm during the first and second campaign, respectively. Overall, we found that only 32 ± 19 % of the carbon was exported by CO2 evasion, while the rest was exported by discharge. CO2 outgassing seemed to be moderated by the short water residence time. Since most Southeast Asian peatlands are located at the coast, this is probably an important limiting factor for CO2 outgassing from most of its peat-draining rivers.

Interfingering of the Frontier Formation and Aspen Shale, Cumberland Gap, Wyoming.

USGS Publications Warehouse

M'gonigle, J.

1982-01-01

The basal part, or the Chalk Creek Member, of the non-marine lower Frontier Formation (Upper Cretaceous) includes a thin coal bed that grades S into a carbonaceous shale. The latter plus associated sandstones and shales pinch out S of Cumberland Gap and lie stratigraphically below the top of the Aspen Shale. The beds in the upper part of the Aspen, in turn, pinch out within the Frontier Formation. The coal bed and equivalent carbonaceous shale represent in-place accumulation of peat. The interfingering suggests that in SW Wyoming the Lower/Upper Cretaceous boundary is within the Chalk Creek Member. -from Author

Enhanced greenhouse gas emissions from the Arctic with experimental warming

NASA Astrophysics Data System (ADS)

Voigt, Carolina; Lamprecht, Richard E.; Marushchak, Maija E.; Lind, Saara E.; Novakovskiy, Alexander; Aurela, Mika; Martikainen, Pertti J.; Biasi, Christina

2017-04-01

Temperatures in the Arctic are projected to increase more rapidly than in lower latitudes. With temperature being a key factor for regulating biogeochemical processes in ecosystems, even a subtle temperature increase might promote the release of greenhouse gases (GHGs) to the atmosphere. Usually, carbon dioxide (CO2) and methane (CH4) are the GHGs dominating the climatic impact of tundra. However, bare, patterned ground features in the Arctic have recently been identified as hot spots for nitrous oxide (N2O). N2O is a potent greenhouse gas, which is almost 300 times more effective in its global warming potential than CO2; but studies on arctic N2O fluxes are rare. In this study we examined the impact of temperature increase on the seasonal GHG balance of all three important GHGs (CO2, CH4 and N2O) from three tundra surface types (vegetated peat soils, unvegetated peat soils, upland mineral soils) in the Russian Arctic (67˚ 03' N 62˚ 55' E), during the course of two growing seasons. We deployed open-top chambers (OTCs), inducing air and soil surface warming, thus mimicking predicted warming scenarios. We combined detailed CO2, CH4 and N2O flux studies with concentration measurements of these gases within the soil profile down to the active layer-permafrost interface, and complemented these GHG measurements with detailed soil nutrient (nitrate and ammonium) and dissolved organic carbon (DOC) measurements in the soil pore water profile. In our study, gentle air warming (˜1.0 ˚ C) increased the seasonal GHG release of all dominant surface types: the GHG budget of vegetated peat and mineral soils, which together cover more than 80 % of the land area in our study region, shifted from a sink to a source of -300 to 144 g CO2-eq m-2 and from -198 to 105 g CO2-eq m-2, respectively. While the positive warming response was governed by CO2, we provide here the first in situ evidence that warming increases arctic N2O emissions: Warming did not only enhance N2O emissions from the known arctic N2O hot spots (bare peat soils; maximum seasonal release with warming: 87 mg N2O m-2), but also from the vegetated peat surfaces, not emitting N2O under present climate. These surfaces showed signs of a hampered plant growth, leading to reduced soil N uptake with warming, indicating that plants are regulating arctic N2O emissions. The warming treatment was limited to temperature of air and upper soil surface, and did not alter thaw depth. Nonetheless, we observed a clear increase of all three GHGs deep in the soil profile, and attribute this to downward leaching of labile organic substances from the surface soil and/or plants, fueling microbial activity at depth. Our study thus highlights the tight interlinkage between the surface soil, vegetation, and deeper soil layers, which could lead to losses of all three GHGs, including N2O, with subtle temperature increase. We therefore emphasize that indirect effects caused by warming, such as leaching processes, as well as arctic N2O emissions, need to be taken into account when attempting to project feedbacks between the arctic and the global climate system.

Dissolved Organic Carbon Cycling and Transformation Dynamics in A Northern Forested Peatland

NASA Astrophysics Data System (ADS)

Tfaily, M. M.; Lin, X.; Chanton, P. R.; Steinweg, J.; Esson, K.; Kostka, J. E.; Cooper, W. T.; Schadt, C. W.; Hanson, P. J.; Chanton, J.

2013-12-01

Peatlands sequester one-third of all soil carbon and currently act as major sinks of atmospheric carbon dioxide. The ability to predict or simulate the fate of stored carbon in response to climatic disruption remains hampered by our limited understanding of the controls of carbon turnover and the composition and functioning of peatland microbial communities. A combination of advanced analytical chemistry and microbiology approaches revealed that organic matter reactivity and microbial community dynamics were closely coupled in an extensive field dataset compiled at the S1 bog site established for the SPRUCE program, Marcell Experimental Forest (MEF). The molecular composition and decomposition pathways of dissolved organic carbon (DOC) were contrasted using parallel factor (PARAFAC)-modeled excitation emission fluorescence spectroscopy (EEMS) and FT-ICR MS. The specific UV absorbance (SUVA) at 254 nm was calculated as an indicator of aromaticity. Fluorescence intensity ratios (BIX and FI) were used to infer the relative contributions from solid phase decomposition and microbial production. Distributions of bulk DOC, its stable (δ13C) and radioactive (Δ14C) isotopic composition were also utilized to infer information on its dynamics and transformation processes. Strong vertical stratification was observed in organic matter composition, the distribution of mineralization products (CO2, CH4), respiration rates, and decomposition pathways, whereas smaller variations were observed between sites. A decline in the aromaticity of pore water DOC was accompanied by an increase in microbially-produced DOC. Solid phase peat, on the other hand, became more humified and highly aromatic with depth. These observations were consistent with radiocarbon data that showed that the radiocarbon signatures of microbial respiration products in peat porewaters more closely resemble those of DOC rather than solid peat, indicating that carbon from recent photosynthesis is fueling the majority of the decomposition, even in the subsurface. Stable isotope geochemistry paralleled with vertical changes in methanogen community composition to reveal a mid-depth maximum in acetoclastic methanogenesis, while hydrogenotrophic methanogenesis appears to dominate deeper peat layers. Archaea increased in relative abundance with depth, comprising up to 60 % of the microbial community in the deep peat below 75 cm depth. The Crenarchaeota, Archaea that are not known to produce methane, are suggested to play a critical role in the carbon cycle of deeper peat layers. This is corroborated by evidence from a C isotope mass balance, which indicates that processes other than methanogenesis (fermentation, anaerobic respiration) predominate in the deep peat leading to dominance of CO2 production at depth.

Soil property effects on wind erosion of organic soils

USDA-ARS?s Scientific Manuscript database

Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion r...

Soil Property Effects on Wind Erosion of Organic Soils

USDA-ARS?s Scientific Manuscript database

Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion r...

SPRUCE Deep Peat Heating Manipulations: in situ Methods to Characterize the Response of Deep Peat to Warming

NASA Astrophysics Data System (ADS)

Hanson, P. J.; Riggs, J. S.; Barbier, C. N.; Nettles, W. R., IV; Phillips, J. R.; Hook, L.

2014-12-01

Deep soil heating infrastructure was completed in 2014 for a peatland whole-ecosystem warming study that will include air warming starting in 2015 (SPRUCE; http://mnspruce.ornl.gov). In June 2014, we initiated deep soil heating to test the responsiveness of deep peat carbon stocks, microbial communities and biogeochemical cycling processes to heating at 4 warming levels (+2.25, +4.5, +6.75 and +9 °C; 2 replicate plots) compared to fully-constructed control plots (+0 °C; 2 replicate plots). The warming treatments were deployed over eight 113 m2 areas using circular arrays of low-wattage (W) electrical resistance heaters. Perimeter heating was achieved by an exterior circle of 48 100W heaters that apply heat from the surface to a depth of 3 meters. Heating within the study area was accomplished utilizing three zones of 100W "deep only" heaters: an intermediate circle of 12 units, an interior circle of 6 units and one unit placed at the plot center. Heating elements inside the study area apply heat only from -2 to -3 m to keep active heater surfaces away from measured peat volumes. With an average peat depth of 2.5 meters this system was able to warm approximately 113 of the 282 m3 of peat within each target plot. In the absence of the air warming cap, in situ deep peat heating is only effective at sustaining warming in the deep peat layers. Warming levels at depth were achieved over a 25-day (+ 2.25 °C) to a 60-day (+9 °C) period depending on the target treatment temperatures in agreement with a priori energy balance model simulations. Homogeneous temperature distributions between heaters at a given depth interval continued to develop after these targets were reached. Biological and biogeochemical responses to these manipulations are being actively assessed. After one month of transient heating, data for ground-level surface flux of CO2 and CH4 had not shown changes from deep peat heating, but they continue to be tracked and will be summarized in this and related talks.

Prediction of ultrasonic pulse velocity for enhanced peat bricks using adaptive neuro-fuzzy methodology.

PubMed

Motamedi, Shervin; Roy, Chandrabhushan; Shamshirband, Shahaboddin; Hashim, Roslan; Petković, Dalibor; Song, Ki-Il

2015-08-01

Ultrasonic pulse velocity is affected by defects in material structure. This study applied soft computing techniques to predict the ultrasonic pulse velocity for various peats and cement content mixtures for several curing periods. First, this investigation constructed a process to simulate the ultrasonic pulse velocity with adaptive neuro-fuzzy inference system. Then, an ANFIS network with neurons was developed. The input and output layers consisted of four and one neurons, respectively. The four inputs were cement, peat, sand content (%) and curing period (days). The simulation results showed efficient performance of the proposed system. The ANFIS and experimental results were compared through the coefficient of determination and root-mean-square error. In conclusion, use of ANFIS network enhances prediction and generation of strength. The simulation results confirmed the effectiveness of the suggested strategies. Copyright © 2015 Elsevier B.V. All rights reserved.

A wetland aquifer interaction test

NASA Astrophysics Data System (ADS)

Wise, W. R.; Annable, M. D.; Walser, J. A. E.; Switt, R. S.; Shaw, D. T.

2000-01-01

An understanding of the hydraulic connectivity between an isolated wetland and its underlying groundwater is required to help assess the ecological impact that changes in the groundwater level may induce. Literature values for the hydraulic conductivity of peat vary up to ten orders of magnitude, indicating the absolute necessity of obtaining site-specific information. Horizontal and vertical variability in peat layers makes the process of extrapolating point-based measurements to predict system-level behavior difficult. By inducing or augmenting a flow up from the underlying aquifer into the wetland through a rapid lowering of wetland water level, the system-level hydraulic connectivity of a wetland to the groundwater may be directly measured. At a study site, a small, seasonally flooded depression mash wetland in Florida, the method and subsequent analysis yielded a value for the hydraulic resistance of the organic layer of 6 days, indicating a significant connection between the wetland and the aquifer.

Substrate-induced growth and isolation of Acidobacteria from acidic Sphagnum peat.

PubMed

Pankratov, Timofei A; Serkebaeva, Yulia M; Kulichevskaya, Irina S; Liesack, Werner; Dedysh, Svetlana N

2008-05-01

Fluorescence in situ hybridization (FISH) was applied to estimate the population size of the poorly characterized phylum Acidobacteria in acidic peat sampled from nine different Sphagnum-dominated wetlands of Northern Russia. The cell numbers of these bacteria in oxic peat layers ranged from 0.4 x 10(6) to 1.3 x 10(7) cells per g of wet peat, comprising up to 4% of total bacterial cells. Substrate-induced growth of acidobacteria was observed after amendment of peat samples with glucose, pectin, xylan, starch, ethanol and methanol, while weak or no response was obtained for acetate, pyruvate, mannitol and cellobiose. Using low-nutrient media and FISH-mediated monitoring of the isolation procedure, we succeeded in obtaining nine strains of acidobacteria in pure cultures. These strains belonged to subdivisions 1 and 3 of the Acidobacteria and represented strictly aerobic, heterotrophic organisms. Except for methanol, the substrate utilization patterns of these isolates matched the results obtained in our substrate-amendment experiments with native peat. All strains were also capable of utilizing galacturonic acid, a characteristic component of the cell wall in Sphagnum spp, which is released during moss decomposition. Most isolates from subdivision 1 were truly acidophilic organisms with the growth optimum at pH 3.5-4.5, while the isolates from subdivision 3 grew optimally at pH 5.5-6.5. Another important phenotypic trait of novel strains was their capability of active growth at low temperatures. Both acidophily and low-temperature growth are consistent with the occurrence of acidobacteria in cold and acidic northern wetlands.

Deccesion of peat-moorsh soils under different land use

NASA Astrophysics Data System (ADS)

Lipka, K.; Zając, E.

2009-04-01

Use of peatlands has a serious impact on soil properties as well as on loss of organic matter. On the basis of survey carried out in 1976, 1993 and 2001 in the Mrowla river valley near Rzeszow, authors analysed changes of the peat-moorsh soils under different land use. The 25- year period was analysed. Survey results comprised: loss of organic matter, advance of moorsh forming process and change of prognostic soil-moisture complexes (after Okruszko). Stratigraphic profiles made in the years1996-2001 were compared and rate of organic mass loss was calculated. The highest values were stated for ploughfields with crop rotation (root plants, industrial plants and cereals). Intensified soil aeration and moorsh forming process as well as wind erosion caused gradual lowering of ground level. Depth of degraded peat layer in roof of surveyed peat deposits was between 0,2 and 0,8 m. Ground surface was lowering of 1,68 cm per year. It was found that, for ploughfields especially, peat-moorhs soil showing medium degree of moorsh forming process (MtII) and prognostic soil-moisture complex BC (periodically drying), after 17 years already, had changed into a soil with high degree of moorsh forming process (MtIII) and prognostic soil-moisture complex C (drying). For meadows and pastures land used such evident change wasn't noticed. During the whole investigation period (25 years) mean lowering of the peat-moorsh soils level along transects lines for different land use was: 1,15 cm per year for meadows and pastures, 1,58 cm pea year for plougfields and 1,38 cm per year for alder wood.

Dynamics of organic carbon stock of Estonian arable and grassland peat soils

NASA Astrophysics Data System (ADS)

Kauer, Karin; Tammik, Kerttu; Penu, Priit

2016-04-01

Peat soils represent globally a major reserve of soil organic carbon (SOC). Estimation of changes in SOC stocks is important for understanding soil carbon sequestration and dynamics of greenhouse gas emissions. The aim of this study was to estimate the SOC stock of Estonian agricultural peat soils and SOC stock change depending on land use type (arable land and long-term grasslands (over 5 years)). The soils were classified as Histosols according to WRB classification. Generally the arable land was used for growing cereals, oilseed rape, legumes and used as ley in crop rotation. The main technique of soil cultivation was ploughing. During 2002-2015 the soil samples of 0-20 cm soil layer (one average soil sample per 1-5 ha) were collected. The SOC content was measured by NIRS method. The SOC stock was calculated by assuming that soil mean bulk density is 0.3 g cm-3. The SOC stock change in arable land was estimated during 3-13 years (N=91) and in grassland 4-13 year (N=163). The average SOC content of peat soils varied from 150.6 to 549.0 mg g-1. The initial SOC stock of arable land was 271.3 t ha-1 and of grassland 269.3 t ha-1. The SOC stock declined in arable peat soils faster (-2.57 t ha-1 y-1) compared to the changes in grassland peat soils (-0.67 t ha-1 y-1). According to the length of the study period the SOC stock change per year varied from -5.14 to 6.64 t ha-1 y-1 in grasslands and from -14.78 to 0.83 t ha-1 y-1 in arable land, although there was no clear relationship between the SOC stock change and the length of the study period. More detailed information about the properties of agricultural land and land use history is needed to analyse the causes of the SOC stock changes in agricultural peat soils. However, from the current research we can conclude that the SOC stock of arable and grassland peat soils is declining during the cultivation. These decreases are important to specify when considering the role of peat soils in atmospheric greenhouse gas balances considering peat soils spatial variability related to regional and local differences in ecology, hydrology and climate.

Uranium delivery and uptake in a montane wetland, north-central Colorado, USA

USGS Publications Warehouse

Schumann, R. Randall; Zielinski, Robert A.; Otton, James K.; Pantea, Michael P.; Orem, William H.

2017-01-01

Comprehensive sampling of peat, underlying lakebed sediments, and coexisting waters of a naturally uraniferous montane wetland are combined with hydrologic measurements to define the important controls on uranium (U) supply and uptake. The major source of U to the wetland is groundwater flowing through locally fractured and faulted granite gneiss of Proterozoic age. Dissolved U concentrations in four springs and one seep ranged from 20 to 83 ppb (μg/l). Maximum U concentrations are ∼300 ppm (mg/kg) in lakebed sediments and >3000 ppm in peat. Uranium in lakebed sediments is primarily stratabound in the more organic-rich layers, but samples of similar organic content display variable U concentrations. Post-depositional modifications include variable additions of U delivered by groundwater. Uranium distribution in peat is heterogeneous and primarily controlled by proximity to groundwater-fed springs and seeps that act as local point sources of U, and by proximity to groundwater directed along the peat/lakebeds contact. Uranium is initially sorbed on various organic components of peat as oxidized U(VI) present in groundwater. Selective extractions indicate that the majority of sorbed U remains as the oxidized species despite reducing conditions that should favor formation of U(IV). Possible explanations are kinetic hindrances related to strong complex formation between uranyl and humic substances, inhibition of anaerobic bacterial activity by low supply of dissolved iron and sulfate, and by cold temperatures.

An in situ occurrence of coal balls in the Amburgy coal bed, Pikeville Formation (Duckmantian), central Appalachian Basin, USA

USGS Publications Warehouse

Greb, S.F.; Eble, C.F.; Chesnut, D.R.; Phillips, T.L.; Hower, J.C.

1999-01-01

Carbonate concretions containing permineralized peat, commonly called coal balls, were encountered in the Amburgy coal, a generally low-ash (9.4%), but commonly high-sulfur (3.6%), Middle Pennsylvanian coal of the Eastern Kentucky Coal Field. These are the first coal balls from the Amburgy coal, and one of only a few reported occurrences from the central Appalachian Basin. The coal balls occur in the upper part of the coal, between two paleochannel cut-outs at the top of the Pikeville Formation, and immediately beneath a scour with a marine fossil lag at the base of the Kendrick Shale Member, Hyden Formation. The coal is thickest (1.3 m) in a narrow (<300 m), elongate depression between the bounding paleochannels, and thins toward the occurrence of coal balls. Total biovolume as measured from acetate peels of coal balls indicates cordaites or lycopsid (36.1% each) dominance. Vertical sampling through one coal-ball aggregate shows zoning from a lower cordaites-dominant (88.7%) assemblage, to a middle, degraded, sphenopsid-rich assemblage, to an upper lycopsid-dominant (88.6%) assemblage. Beneath the coal balls, palynologic and petrographic analyses indicate the basal and middle portions of the bed are dominated by arborescent lycopsid spores and cordaites pollen, and by vitrinite macerals. The top part of the bed, above the coal balls, contains increased intertinite macerals, increased percentages of small fern spores, and variable ash yield (5-21%). Thickening of the Amburgy coal along a structural low, in combination with basal high-ash yields, vitrinite-dominance, and heterogenous palynoflora, indicate paleotopographic control on initial peat accumulation. Abundant lycopsid spores in the basal and middle part of the coal reflect rheotrophic conditions consistent with accumulation in a paleotopographic depression. Apparent zonation preserved in one of the coal-ball masses may document plant successions in response to flooding. Similar percentages of cordaites and lycopods, respectively, in the zones above and below the degraded incursion interval reflect development of a mixed, successional pattern in response to the flooding. Coal-ball formation may have been facilitated by channeling along the Kendrick ravinement, within a paleotopographic depression, at the split margin of the Amburgy peat, either through direct transmittal of carbonates and marine waters into the peat, or through degassing of the peat beneath the scour.

Depositional history of the Fire Clay coal bed (Late Duckmantian), Eastern Kentucky, USA

USGS Publications Warehouse

Greb, S.F.; Eble, C.F.; Hower, J.C.

1999-01-01

More than 3800 coal thickness measurements, proximate analyses from 97 localities, and stratigraphic and sedimentological analyses from more than 300 outcrops and cores were used in conjunction with previously reported palynological and petrographic studies to map individual benches of the coal and document bench-scale variability in the Fire Clay (Hazard No. 4) coal bed across a 1860 km2 area of the Eastern Kentucky Coal Field. The bench architecture of the Fire Clay coal bed consists of uncommon leader benches, a persistent but variable lower bench, a widespread, and generally thick upper bench, and local, variable rider benches. Rheotrophic conditions are inferred for the leader benches and lower bench based on sedimentological associations, mixed palynomorph assemblages, locally common cannel coal layers, and generally high ash yields. The lower bench consistently exhibits vertical variability in petrography and palynology that reflects changing trophic conditions as topographic depressions infilled. Infilling also led to unconfined flooding and ultimately the drowning of the lower bench mire. The drowned mire was covered by an air-fall volcanic-ash deposit, which produced the characteristic flint clay parting. The extent and uniform thickness of the parting suggests that the ash layer was deposited in water on a relatively flat surface without a thick canopy or extensive standing vegetation across most of the study area. Ash deposits led to regional ponding and establishment of a second planar mire. Because the topography had become a broadly uniform, nutrient-rich surface, upper-bench peats became widespread with large areas of the mire distant to clastic sources. Vertical sections of thick (> 70 cm), low-ash yield, upper coal bench show a common palynomorph change from arborescent lycopod dominance upward to fern and densospore-producing, small lycopod dominance, inferred as a shift from planar to ombrotrophic mire phases. Domed mires appear to have been surrounded by wide areas of planar mires, where the coal was thinner (< 70 cm), higher in ash yield, and dominated by arborescent lycopods. Rectangular thickness trends suggest that syndepositional faulting influenced peat accumulation, and possibly the position of the domed mire phase. Faulting also influenced post-depositional clastic environments of deposition, resulting in sandstone channels with angular changes in orientation. Channels and lateral facies were locally draped by high-ash-yield rider coal benches, which sometimes merged with the upper coal bench. These arborescent-lycopod dominant rider coal benches were profoundly controlled by palcotopography, much like the leader coal benches. Each of the benches of coal documented here represent distinctly different mires that came together to form the Fire Clay coal bed, rather than a single mire periodically split by clastic influx. This is significant as each bench of the coal has its own characteristics, which contribute to the total coal characteristics. The large data set allows interpretation of both vertical and lateral limits to postulated domed phases in the upper coal bench, and to the delineation of subtle tectonic structures that allow for meaningful thickness projections beyond the limits of present mining.A study was conducted to analyze the depositional history of the Fire Clay coal bed in the eastern Kentucky coal field. The study involved over 3800 coal thickness measurements, proximate analyses from 97 localities, and stratigraphic and sedimentological analyses from more than 300 outcrops and cores in conjunction with previously reported palynological and petrographic studies to map individual benches of the coal and document bench-scale variability.

Paleoecological interpretation of a middle Pennsylvanian coal bed in the central Appalachian basin, U.S.A.

USGS Publications Warehouse

Eble, C.F.; Grady, W.C.

1990-01-01

At least 180 small spore species assignable to 62 miospore genera have been identified from the Middle Pennsylvanian Hernshaw coal bed in southern West Virginia, and its stratigraphic equivalent, the Fire Clay coal bed, in eastern Kentucky. The established natural affinities of a majority of these miospore taxa indicate that the Hernshaw-Fire Clay peat swamp supported a diverse flora consisting of arborescent and "herbaceous" lycopods, ferns (tree-like and small varities), calamities and cordaites. Four floral groupings are recognized in the Hernshaw-Fire Clay coal bed. The inferred paleoecology and vertical stratification of each of these four floral groupings is similar in structure to the "phasic" floral communities found in modern domed peat systems, suggesting that the ancient Hernshaw-Fire Clay peat swamp was a domed deposit. Compositional characteristics (petrographic make up, ash yield and sulfur content) associated with the four groupings are consistent with, and support this interpretation. Where uninterrupted by inorganic partings, the Hernshaw-Fire Clay coal bed commonly contains basal coal layers dominated by Lycospora-bearing arborescent lycopods, with successive increments showing a progression to a more fern- and "herbaceous"-lycopod-dominant flora in younger layers. These observations are corroborated by petrographic analyses, which show the bed to be compositionally stratified. Increments dominated by Lycospora have high vitrinite contents, in contrast to increments containing increased percentages of fern- and "herbaceous"-lycopod-affiliated taxa that are enriched in inertinite macerals. The volcanic ash fall, preserved as the flint-clay parting in the Hernshaw-Fire Clay coal bed, had a considerable effect on the development of the ancient Hernshaw-Fire Clay peat swamp. Besides interrupting peat formation, the presence of an inorganic substrate represent a major change in edaphic conditions within the swamp. This disruption is demonstrated by a change in palynflora and by the establishment and proliferation of some plant groups, notably cordaites and calamites, that may have been better adapted to growth on mineral soils. These palynologic and petrographic relationships, thought to be indicative of a domed peat-swamp origin, are not confined to the Hernshaw-Fire Clay coal bed, but appear to be characteristic of many coal beds in the Appalachian basin, and also of coal beds in other basins. ?? 1990.

55,000 yrs of Environmental Change in the Southern Hemisphere: Peat Stratigraphy and Inorganic Geochemistry of Lynch's Crater, NE Queensland, Australia.

NASA Astrophysics Data System (ADS)

Muller, J.; Kylander, M. E.; Wust, R. A.; Weiss, D. J.

2005-12-01

This study presents one of the first applications of geochemical proxies to define changes in vegetation, hydrology and atmospheric dust recorded in a peat deposit in the Southern Hemisphere. The Lynch's Crater archive has captured local, regional and global environmental changes and reveals dynamic ecosystem changes as a result of climate shifts over the past 55,000 yrs BP. The 13 m peat record consists of 1.5 m of ombrotrophic peat underlain by a minerotrophic peat. The ombrotrophic section consists of low inorganic content ("ash") and low pH, as expected in of an ombrotrophic environment. The minerotrophic section contains several layers, up to a few cm thick, where abundant sponge spicules, diatom fragments and detrital quartz are indicative of high algal and protista productivity. These layers are characterised by high (up to 50%) ash, indicating persistent flooding of the peat deposits of Lynch's Crater and signalling periods of change in precipitation in North Queensland, Australia. Geochemical data are used to differentiate between climatic episodes associated with flooding events and internal and external atmospheric dust fluxes. Lead isotopes with lithogenic and chalcophile elements tell us that two distinctive sources are prevalent in the Lynch's Crater record. Most of the inorganic fractions of the deposits have the same geochemical signatures as the rocks and sediments of the crater wall, with low As concentrations, high Al, Ti and Sc concentrations and a more radiogenic Pb isotope signature. Influence from long-range dust is distinguished in the lower sections of the core (~35,000-55,000 cal yrs BP) where increases in As concentrations and less radiogenic Pb isotopes are found. Leading up to the Holocene (~35,000-10,000) the influence of increased dust influx becomes more significant (increasing lithogenics, chalcophiles and ash content) and where possible long-range sources are still active, but diluted by a prevailing dominance of the local sources. During the Holocene Pb isotope signatures remain similar but lithogenic and chalcophile concentrations decrease significantly and coincide with the lowest ash values (~4%) in the core. The research shows Lynch's Crater is a sensitive record of past atmospheric dust cylces and precipitation regimes leading to an invaluable record of past environmental change in the Southern Hemisphere.

Surfactant-Modified Soil Amendments Reduce Nitrogen and Phosphorus Leaching in a Sand-Based Rootzone.

PubMed

Shaddox, Travis W; Kruse, Jason K; Miller, Grady L; Nkedi-Kizza, Peter; Sartain, Jerry B

2016-09-01

United States Golf Association putting greens are susceptible to nitrogen (N) and phosphorus (P) leaching. Inorganic soil amendments are used to increase moisture and nutrient retention and may influence N and P leaching. This study was conducted to determine whether N and P leaching could be reduced using soil amendments and surfactant-modified soil amendments. Treatments included a control (sand), sand-peat, zeolite, calcined clay, hexadecyltrimethylammonium-zeolite, and hexadecyltrimethylammonium-calcined clay. Lysimeters were filled with a 30-cm rootzone layer of sand-peat (85:15 by volume), below which a 5-cm treatment layer of amendments was placed. A solution of NO-N, NH-N, and orthophosphate-P (2300, 2480, and 4400 μg mL, respectively) was injected at the top of each lysimeter, and leachate was collected using an autocollector set to collect a 10-mL sample every min until four pore volumes were collected. Uncoated amendments, sand, and peat had no influence on NO-N retention, whereas hexadecyltrimethylammonium-coated amendments reduced NO-N leaching to below detectable limits. Both coated and uncoated amendments reduced NH-N leaching, with zeolite reducing NH-N leached to near zero regardless of hexadecyltrimethylammonium coating. Pure sand resulted in a 13% reduction of applied orthophosphate-P leaching, whereas peat contributed to orthophosphate-P leaching. Surfactant-modified amendments reduced orthophosphate-P leaching by as much as 97%. Surfactant-modified soil amendments can reduce NO-N, NH-N, and orthophosphate-P leaching and, thus, may be a viable option for removing leached N and P before they enter surface or ground waters. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effect of vegetation removal and water table drawdown on the non-methane biogenic volatile organic compound emissions in boreal peatland microcosms

NASA Astrophysics Data System (ADS)

Faubert, Patrick; Tiiva, Päivi; Rinnan, Åsmund; Räty, Sanna; Holopainen, Jarmo K.; Holopainen, Toini; Rinnan, Riikka

2010-11-01

Biogenic volatile organic compound (BVOC) emissions are important in the global atmospheric chemistry and their feedbacks to global warming are uncertain. Global warming is expected to trigger vegetation changes and water table drawdown in boreal peatlands, such changes have only been investigated on isoprene emission but never on other BVOCs. We aimed at distinguishing the BVOCs released from vascular plants, mosses and peat in hummocks (dry microsites) and hollows (wet microsites) of boreal peatland microcosms maintained in growth chambers. We also assessed the effect of water table drawdown (-20 cm) on the BVOC emissions in hollow microcosms. BVOC emissions were measured from peat samples underneath the moss surface after the 7-week-long experiment to investigate whether the potential effects of vegetation and water table drawdown were shown. BVOCs were sampled using a conventional chamber method, collected on adsorbent and analyzed with GC-MS. In hummock microcosms, vascular plants increased the monoterpene emissions compared with the treatment where all above-ground vegetation was removed while no effect was detected on the sesquiterpenes, other reactive VOCs (ORVOCs) and other VOCs. Peat layer from underneath the surface with intact vegetation had the highest sesquiterpene emissions. In hollow microcosms, intact vegetation had the highest sesquiterpene emissions. Water table drawdown decreased monoterpene and other VOC emissions. Specific compounds could be closely associated to the natural/lowered water tables. Peat layer from underneath the surface of hollows with intact vegetation had the highest emissions of monoterpenes, sesquiterpenes and ORVOCs whereas water table drawdown decreased those emissions. The results suggest that global warming would change the BVOC emission mixtures from boreal peatlands following changes in vegetation composition and water table drawdown.

Metabolic potential of fatty acid oxidation and anaerobic respiration by abundant members of Thaumarchaeota and Thermoplasmata in deep anoxic peat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Xueju; Handley, Kim M.; Gilbert, Jack A.

2015-12-01

To probe the metabolic potential of abundant Archaea in boreal peats, we reconstructed two near-complete archaeal genomes, affiliated with Thaumarchaeota group 1.1c (bin Fn1, 8% abundance), which was a genomically unrepresented group, and Thermoplasmata (bin Bg1, 26% abundance), from metagenomic data acquired from deep anoxic peat layers. Each of the near-complete genomes encodes the potential to degrade long-chain fatty acids (LCFA) via β-oxidation. Fn1 has the potential to oxidize LCFA either by syntrophic interaction with methanogens or by coupling oxidation with anaerobic respiration using fumarate as a terminal electron acceptor (TEA). Fn1 is the first Thaumarchaeota genome without an identifiablemore » carbon fixation pathway, indicating that this mesophilic phylum encompasses more diverse metabolisms than previously thought. Furthermore, we report genetic evidence suggestive of sulfite and/or organosulfonate reduction by Thermoplasmata Bg1. In deep peat, inorganic TEAs are often depleted to extremely low levels, yet the anaerobic respiration predicted for two abundant archaeal members suggests organic electron acceptors such as fumarate and organosulfonate (enriched in humic substances) may be important for respiration and C mineralization in peatlands.« less

Repeating cardiopulmonary health effects in rural North Carolina population during a second large peat wildfire.

PubMed

Tinling, Melissa A; West, J Jason; Cascio, Wayne E; Kilaru, Vasu; Rappold, Ana G

2016-01-27

Cardiovascular health effects of fine particulate matter (PM2.5) exposure from wildfire smoke are neither definitive nor consistent with PM2.5 from other air pollution sources. Non-comparability among wildfire health studies limits research conclusions. We examined cardiovascular and respiratory health outcomes related to peat wildfire smoke exposure in a population where strong associations were previously reported for the 2008 Evans Road peat wildfire. We conducted a population-based epidemiologic investigation of associations between daily county-level modeled wildfire PM2.5 and cardiopulmonary emergency department (ED) visits during the 2011 Pains Bay wildfire in eastern North Carolina. We estimated changes in the relative risk cumulative over 0-2 lagged days of wildfire PM2.5 exposure using a quasi-Poisson regression model adjusted for weather, weekends, and poverty. Relative risk associated with a 10 μg/m(3) increase in 24-h PM2.5 was significantly elevated in adults for respiratory/other chest symptoms 1.06 (1.00-1.13), upper respiratory infections 1.13 (1.05-1.22), hypertension 1.05 (1.00-1.09) and 'all-cause' cardiac outcomes 1.06 (1.00-1.13) and in youth for respiratory/other chest symptoms 1.18 (1.06-1.33), upper respiratory infections 1.14 (1.04-1.24) and 'all-cause' respiratory conditions 1.09 (1.01-1.17). Our results replicate evidence for increased risk of cardiovascular outcomes from wildfire PM2.5 and suggest that cardiovascular health should be considered when evaluating the public health burden of wildfire smoke.

Temperature, oxygen, and vegetation controls on decomposition in a James Bay peatland

NASA Astrophysics Data System (ADS)

Philben, Michael; Holmquist, James; MacDonald, Glen; Duan, Dandan; Kaiser, Karl; Benner, Ronald

2015-06-01

The biochemical composition of a peat core from James Bay Lowland, Canada, was used to assess the extent of peat decomposition and diagenetic alteration. Our goal was to identify environmental controls on peat decomposition, particularly its sensitivity to naturally occurring changes in temperature, oxygen exposure time, and vegetation. All three varied substantially during the last 7000 years, providing a natural experiment for evaluating their effects on decomposition. The bottom 50 cm of the core formed during the Holocene Climatic Optimum (~7000-4000 years B.P.), when mean annual air temperature was likely 1-2°C warmer than present. A reconstruction of the water table level using testate amoebae indicated oxygen exposure time was highest in the subsequent upper portion of the core between 150 and 225 cm depth (from ~2560 to 4210 years B.P.) and the plant community shifted from mostly Sphagnum to vascular plant dominance. Several independent biochemical indices indicated that decomposition was greatest in this interval. Hydrolysable amino acid yields, hydroxyproline yields, and acid:aldehyde ratios of syringyl lignin phenols were higher, while hydrolysable neutral sugar yields and carbon:nitrogen ratios were lower in this zone of both vascular plant vegetation and elevated oxygen exposure time. Thus, peat formed during the Holocene Climatic Optimum did not appear to be more extensively decomposed than peat formed during subsequent cooler periods. Comparison with a core from the West Siberian Lowland, Russia, indicates that oxygen exposure time and vegetation are both important controls on decomposition, while temperature appears to be of secondary importance. The low apparent sensitivity of decomposition to temperature is consistent with recent observations of a positive correlation between peat accumulation rates and mean annual temperature, suggesting that contemporary warming could enhance peatland carbon sequestration, although this could be offset by an increasing contribution of vascular plants to the vegetation.

Changing patterns of Pennsylvanian coal-swamp vegetation and implications of climatic control on coal occurrence

USGS Publications Warehouse

Phillips, T.L.; Peppers, R.A.

1984-01-01

Improved regional and interregional stratigraphic correlations of Pennsylvanian strata permit comparisons of vegetational changes in Euramerican coal swamps. The coal-swamp vegetation is known directly from in situ coal-ball peat deposits from more than 65 coals in the United States and Europe. Interpretations of coal-swamp floras on the basis of coal-ball peat studies are extended to broader regional and stratigraphic patterns by use of coal palynology. Objectives of the quantitative analyses of the vegetation in relation to coal are to determine the botanical constituents at the peat stage and their environmental implications for plant growth and peat accumulation. Morphological and paleoecological analyses provide a basis for deducing freshwater regimes of coal swamps. Changes in composition of Pennsylvanian coal-swamp vegetation are quire similar from one paralic coal region to another and show synchrony that is attributable to climate. Paleobotany and paleogeography of the Euramerican province indicate a moist tropical paleoclimate. Rainfall, runoff and evapotranspiration were the variable climatic controls in the distribution of coal-swamp vegetation, peat accumulation and coal resources. In relative terms of climatic wetness the Pennsylvanian Period is divisible into five intervals, which include two relatively drier intervals that developed during the Lower-Middle and Middle-Upper Pennsylvanian transitions. The climate during Early Pennsylvanian time was moderately wet and the median in moisture availability. Early Middle Pennsylvanian was drier, probably seasonally dry-wet; late Middle Pennsylvanian was the wettest in the Midcontinent; early Late Pennsylvanian was the driest; and late Late Pennsylvanian was probably the wettest in the Dunkard Basin. The five climatic intervals represent a general means of dividing coal resources within each region into groups with similar botanical constituents and environments of peat accumulation. Regional differences in basinal geology and climate were significant variables, but the synchronous control of paleoclimate was of primary importance. ?? 1984.

Permafrost thaw and climate warming may decrease the CO2, carbon, and metal concentration in peat soil waters of the Western Siberia Lowland.

PubMed

Raudina, T V; Loiko, S V; Lim, A; Manasypov, R M; Shirokova, L S; Istigechev, G I; Kuzmina, D M; Kulizhsky, S P; Vorobyev, S N; Pokrovsky, O S

2018-09-01

Soil pore waters are a vital component of the ecosystem as they are efficient tracers of mineral weathering, plant litter leaching, and nutrient uptake by vegetation. In the permafrost environment, maximal hydraulic connectivity and element transport from soils to rivers and lakes occurs via supra-permafrost flow (i.e. water, gases, suspended matter, and solutes migration over the permafrost table). To assess possible consequences of permafrost thaw and climate warming on carbon and Green House gases (GHG) dynamics we used a "substituting space for time" approach in the largest frozen peatland of the world. We sampled stagnant supra-permafrost (active layer) waters in peat columns of western Siberia Lowland (WSL) across substantial gradients of climate (-4.0 to -9.1°C mean annual temperature, 360 to 600mm annual precipitation), active layer thickness (ALT) (>300 to 40cm), and permafrost coverage (sporadic, discontinuous and continuous). We analyzed CO 2 , CH 4 , dissolved carbon, and major and trace elements (TE) in 93 soil pit samples corresponding to several typical micro landscapes constituting the WSL territory (peat mounds, hollows, and permafrost subsidences and depressions). We expected a decrease in intensity of DOC and TE mobilization from soil and vegetation litter to the supra-permafrost water with increasing permafrost coverage, decreasing annual temperature and ALT along a latitudinal transect from 62.3°N to 67.4°N. However, a number of solutes (DOC, CO 2 , alkaline earth metals, Si, trivalent and tetravalent hydrolysates, and micronutrients (Mn, Co, Ni, Cu, V, Mo) exhibited a northward increasing trend with highest concentrations within the continuous permafrost zone. Within the "substituting space for time" climate change scenario and northward shift of the permafrost boundary, our results suggest that CO 2 , DOC, and many major and trace elements will decrease their concentration in soil supra-permafrost waters at the boundary between thaw and frozen layers. As a result, export of DOC and elements from peat soil to lakes and rivers of the WSL (and further to the Arctic Ocean) may decrease. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of freeze-thaw cycles on greenhouse gas fluxes from peat soils

NASA Astrophysics Data System (ADS)

Oh, H. D.; Rezanezhad, F.; Markelov, I.; McCarter, C. P. R.; Van Cappellen, P.

2017-12-01

The ongoing displacement of climate zones by global warming is increasing the frequency and intensity of freeze-thaw cycles in middle and high latitude regions, many of which are dominated by organic soils such as peat. Repeated freezing and thawing of soils changes their physical properties, geochemistry, and microbial community structure, which together govern the biogeochemical cycling of carbon and nutrients. In this presentation, we focus on how freeze-thaw cycles influence greenhouse gas fluxes from peat using a newly developed experimental soil column system that simulates realistic soil temperature profiles during freeze-thaw cycles. We measured the surface and subsurface changes to gas and aqueous phase chemistry to delineate the diffusion pathways and quantify soil greenhouse gas fluxes during freeze-thaw cycles using sulfur hexafluoride (SF6) as a conservative tracer. Three peat columns were assembled inside a temperature controlled chamber with different soil structures. All three columns were packed with 40 cm of undisturbed, slightly decomposed peat, where the soil of two columns had an additional 10 cm layer on top (one with loose Sphagnum moss and one with an impermeable plug). The results indicate that the release of SF6 and CO2 gas from the soil surface was influenced by the recurrent development of a physical ice barrier, which prevented gas exchange between the soil and atmosphere during freezing conditions. With the onset of thawing a pulse of SF6 and CO2 occurred, resulting in a flux of 3.24 and 2095.52 µmol/m2h, respectively, due to the build-up of gases in the liquid-phase pore space during freezing. Additionally, we developed a model to determine the specific diffusion coefficients for each peat column. These data allow us to better predict how increased frequency and intensity of freeze-thaw cycles will affect greenhouse gas emissions in northern peat soils.

Northern Peatland Shifts Under Changing Climate and Their Impact on Permafrost

NASA Astrophysics Data System (ADS)

Shur, Y.; Jorgenson, T.; Kanevskiy, M. Z.

2014-12-01

Formation of peatlands depends primarily on climate and its interactions with hydrology, soil thermal regimes, plant composition, and nutrients. A water balance with precipitation exceeding evaporation is necessary for their formation. The rate of peat accumulation also greatly depends on thermal resources. The prominent impact of the water balance and temperature on peatland formation is evident in the West Siberia Lowland. The rate of peat accumulation steadily increases from arctic tundra to moss tundra, to forest tundra, to northern taiga, and to southern taiga. This increase is a result in increase in air temperature and length of the growing season because all of these zones have water balance favorable for peat formation. Further to south, evaporation prevails over precipitation and peat formation occurs only in isolated areas. Climate change will redefine geographical distribution of climatic and vegetation zones. It is predicted that in arctic and subarctic regions the difference between precipitation and evaporation will increase and as a result these regions will remain favorable to peat accumulation. With increase of thermal resources, the rate of peat accumulation will also increase. The Alaska Arctic Coastal Plain is of a special interest because it has thousands of shallow lakes, which due to warming climate would shift from open waterbodies to peatlands through shoreline paludification and infilling. The accumulation of organic matter will likely turn open water into shore fens and bogs, and eventually to peat plateaus, as is occurring in many boreal landscapes. Expected impact on permafrost in arctic and subarctic regions will include rise of the permafrost table, thickening of the ice-rich intermediate layer with ataxitic (suspended) cryostructure, and replacement of frost boils with earth hummocks. In the contemporary continuous permafrost zone, permafrost formed as climate-driven will be transformed into climate-driven ecosystem protected. Sphagnum mosses, which grow better under warm climates, is a dominant factor in this transformation. Terrestrialization of numerous shallow lakes on the Arctic Coastal Plain of Alaska will lower permafrost temperatures beneath them and in surrounding areas.

Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota: Pore Water DOM composition in a peat bog

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tfaily, Malak M.; Wilson, Rachel M.; Cooper, William T.

We characterized dissolved organic matter (DOM) composition throughout the peat column at the Marcell S1 forested bog in northern Minnesota and tested the hypothesis that redox oscillations associated with cycles of wetting and drying at the surface of the fluctuating water table correlate with increased carbon, sulfur and nitrogen turn over. We found significant vertical stratification of DOM molecular composition and EEM-PARAFAC components within the peat column. In particular the intermediate depth zone (~ 50 cm) was identified as a zone where maximum decomposition and turnover is taking place. Surface DOM was dominated by inputs from surface vegetation. The intermediate-depthmore » zone was an area of high organic matter reactivity and increased microbial activity with diagenetic formation of many unique compounds, among them polycyclic aromatic compounds (PAC) that contain both nitrogen and sulfur heteroatoms. These compounds have been previously observed in coal-derived compounds and were assumed to be responsible for coal's biological activity. Biological processes triggered by redox oscillations taking place at the intermediate depth zone of the peat profile at the S1 bog are assumed to be responsible for the formation of these heteroatomic PACs in this system. Alternatively these compounds could stem from black carbon and nitrogen derived from fires that have occurred at the site in the past. Surface and deep DOM exhibited more similar characteristics, compared to the intermediate-depth zone, with the deep layer exhibiting greater input of microbially degraded organic matter than the surface suggesting that the entire peat profile consists of similar parent material at different degrees of decomposition and that lateral and vertical advection of pore water from the surface to the deeper horizons is responsible for such similarities. Our findings suggest that molecular composition of DOM in peatland pore water is dynamic and is a function of ecosystem activity, water table and redox oscillation and porewater advection.« less

Identification of runoff formation with two dyes in a mid-latitude mountain headwater

NASA Astrophysics Data System (ADS)

Vlček, Lukáš; Falátková, Kristýna; Schneider, Philipp

2017-06-01

Subsurface flow in peat bog areas and its role in the hydrologic cycle has garnered increased attention as water scarcity and floods have increased due to a changing climate. In order to further probe the mechanisms in peat bog areas and contextualize them at the catchment scale, this experimental study identifies runoff formation at two opposite hillslopes in a peaty mountain headwater; a slope with organic peat soils and a shallow phreatic zone (0.5 m below surface), and a slope with mineral Podzol soils and no detectable groundwater (> 2 m below surface). Similarities and differences in infiltration, percolation and preferential flow paths between both hillslopes could be identified by sprinkling experiments with Brilliant Blue and Fluorescein sodium. To our knowledge, this is the first time these two dyes have been compared in their ability to stain preferential flow paths in soils. Dye-stained soil profiles within and downstream of the sprinkling areas were excavated parallel (lateral profiles) and perpendicular (frontal profiles) to the slopes' gradients. That way preferential flow patterns in the soil could be clearly identified. The results show that biomat flow, shallow subsurface flow in the organic topsoil layer, occurred at both hillslopes; however, at the peat bog hillslope it was significantly more prominent. The dye solutions infiltrated into the soil and continued either as lateral subsurface pipe flow in the case of the peat bog, or percolated vertically towards the bedrock in the case of the Podzol. This study provides evidence that subsurface pipe flow, lateral preferential flow along decomposed tree roots or logs in the unsaturated zone, is a major runoff formation process at the peat bog hillslope and in the adjacent riparian zone.

Bearing capacity of helical pile foundation in peat soil from different, diameter and spacing of helical plates

NASA Astrophysics Data System (ADS)

Fatnanta, F.; Satibi, S.; Muhardi

2018-03-01

In an area dominated by thick peat soil layers, driven piles foundation is often used. These piles are generally skin friction piles where the pile tips do not reach hard stratum. Since the bearing capacity of the piles rely on the resistance of their smooth skin, the bearing capacity of the piles are generally low. One way to increase the bearing capacity of the piles is by installing helical plates around the pile tips. Many research has been performed on helical pile foundation. However, literature on the use of helical pile foundation on peat soil is still hardly found. This research focus on the study of axial bearing capacity of helical pile foundation in peat soil, especially in Riau Province. These full-scale tests on helical pile foundation were performed in a rectangular box partially embedded into the ground. The box is filled with peat soil, which was taken from Rimbo Panjang area in the district of Kampar, Riau Province. Several helical piles with different number, diameter and spacing of the helical plates have been tested and analysed. The tests result show that helical pile with three helical plates of uniform diameter has better bearing capacity compared to other helical piles with varying diameter and different number of helical plates. The bearing capacity of helical pile foundation is affected by the spacing between helical plates. It is found that the effective helical plates spacing for helical pile foundation with diameter of 15cm to 35cm is between 20cm to 30cm. This behaviour may be considered to apply to other type of helical pile foundations in peat soil.

The association of uranium with organic matter in Holocene peat: An experimental leaching study

USGS Publications Warehouse

Zielinski, R.A.; Meier, A.L.

1988-01-01

Uraniferous peat was sampled from surface layers of a Holocene U deposit in northeastern Washington State. Dried, sized, and homogenized peat that contained 5980 ??307 ppm U was subjected to a variety of leaching conditions to determine the nature and strength of U-organic bonding in recently accumulated organic matter. The results complement previous experimental studies of U uptake on peat and suggest some natural or anthropogenic disturbances that are favorable for remobilizing U. The fraction of U leached in 24 h experiments at 25??C ranged from 0 to 95%. The most effective leach solutions contained anions capable of forming stable dissolved complexes with uranyl (UO2+2) cation. These included H2SO4 (pH = 1.5) and concentrated (>0.01 M) solutions of sodium bicarbonate-carbonate (pH = 7.0-10.0), or sodium pyrophosphate (pH = 10). Effective leaching by carbonate and pyrophosphate in the absence of added oxidant, and the insignificant effect of added oxidant (as pressurized O2) strongly suggest that U is initially fixed on organic matter as an oxidized U(VI) species. Uranium is more strongly bound than some other polyvalent cations, based on its resistance to exchange in the presence of large excesses of dissolved Ca2+ and Cu2+. Measurements of the rate of U leaching indicate faster rates in acid solution compared to carbonate solution, and are consisten with simultaneous attack of sites with different affinities for U. Sulfuric acid appears a good choice for commercial extraction of U from mined peat. In situ disturbances such as overliming of peat soils, addition of fertilizers containing pyrophosphate, or incursions of natural carbonate-rich waters could produce significant remobilization of U, and possibly compromise the quality of local domestic water supplies. ?? 1988.

Petrology and palynology of the No. 5 block coal bed, northeastern Kentucky

USGS Publications Warehouse

Hower, J.C.; Eble, C.F.; Rathbone, R.F.

1994-01-01

The upper Middle Pennsylvanian (middle Westphalian D equivalent) No. 5 Block coal bed (Eastern Kentucky Coal Field of the Central Appalachian Basin) is a low-sulfur, compliance coal resource, dominantly comprised of dull, inertinite-rich lithotypes. Ash yields tend to be highly variable in the No. 5 Block, as does bed thickness and frequency of bed splitting. This study describes the petrographic, palynologic and geochemical characteristics of the No. 5 Block coal bed, and reports on some temporal and spatial trends among these parameters in eastern-northeastern Kentucky. Petrographically the No. 5 Block coal is predominated by dull, often high-ash lithotypes, with inertinite contents commonly exceeding 30% (mmf). The coal thins to the north-northwest where it tends to be higher in vitrinite and sulfur content. Representatives of large and small lycopsids and ferns (both tree-like and small varieties) dominate the No. 5 Block coal bed palynoflora. Calamite spores and cordaite pollen also occur but are less abundant. Small lycopsid (Densosporites spp. and related crassicingulate genera) and tree fern (e.g. Punctatisporites minutus, Laevigatosporites globosus) spore taxa are most abundant in dull lithotypes. Bright lithotypes contain higher percentages of arboreous lycopsid spores (Lycospora spp.). Regionally, the No. 5 Block coal contains abundant Torispora securis, a tree fern spore specially adapted for desiccation prevention. This, along with overall high percentages of inertinite macerals, suggest that peat accumulation may have taken place in a seasonally dry (?) paleoclimate. The No. 5 Block coal bed thickens rather dramatically in a NW-SE direction, as does the frequency of coal bed splitting. This phenomenon appears to be related to increased accomodation space in the southeastern portion of the study area, perhaps via penecontemporaneous growth faulting. Maceral and palynomorph variations within the bed correspond with these changes. Thin coal along the northwestern margin tends to be vetrinite rich and contains abundant Lycospora, perhaps reflecting relatively stable peat-forming conditions. Thicker coal to the southeast contains more inertinite, high-ash coal layers, and inorganic partings. Spore floras contain more small lycopsid and tree fern components and are temporally variable, perhaps indicating a more unstable peat-forming environment. ?? 1994.

Do storage dynamics in hydropedological units control hydrological connectivity? (Invited)

NASA Astrophysics Data System (ADS)

Tetzlaff, D.; Birkel, C.; Dick, J.; Geris, J.; Soulsby, C.

2013-12-01

In many northern landscapes, peat-dominated riparian wetlands often characterise the zone of connection between terrestrial drainage and the river network. In order to understand the relationship between connectivity and stream flow generation in a montane headwater catchment, we examined the storage dynamics and isotopic composition of soil water in major hydropedological units. These formed a classic catena sequence for northern catchments from free-draining podzols on steep upper hillslopes through to peaty gleysols in lower receiving slopes to deeper peats (Histosols) in the riparian zone. The peaty gleys and peats remained saturated throughout the year, whilst the podzols showed distinct wetting and drying cycles. In this climatic region, most precipitation events are less than 10mm in magnitude, storm runoff is mainly generated from the Histosols and Gleysols, with runoff coefficients (RCs) typically <10%. In larger events the podzolic soils become strongly connected to the saturated areas and RCs can exceed 40%. Isotopic variations in precipitation are significantly damped in the organic-rich surface horizons of the soils due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the strongly reflects that of the near surface waters in the riparian peats. Old 'pre-event' water generally accounts for >80% of flow, even in large events, mainly reflecting the displacement of water stored in the riparian peats and peaty gleys. These riparian areas appear to be the dominant zone where different catchment source waters mix; acting as an 'isostat' that regulates the isotopic composition of stream waters and integrates the Transit Time Distribution (TTD) for the catchment.

The use of plant-specific pyrolysis products as biomarkers in peat deposits

NASA Astrophysics Data System (ADS)

Schellekens, Judith; Bradley, Jonathan A.; Kuyper, Thomas W.; Fraga, Isabel; Pontevedra-Pombal, Xabier; Vidal-Torrado, Pablo; Abbott, Geoffrey D.; Buurman, Peter

2015-09-01

Peatlands are archives of environmental change that can be driven by climate and human activity. Proxies for peatland vegetation composition provide records of (local) environmental conditions that can be linked to both autogenic and allogenic factors. Analytical pyrolysis offers a molecular fingerprint of peat, and thereby a suite of environmental proxies. Here we investigate analytical pyrolysis as a method for biomarker analysis. Pyrolysates of 48 peatland plant species were compared, comprising seventeen lichens, three Sphagnum species, four non-Sphagnum mosses, eleven graminoids (Cyperaceae, Juncaceae, Poaceae), five Ericaceae and six species from other families. This resulted in twenty-one potential biomarkers, including new markers for lichens (3-methoxy-5-methylphenol) and graminoids (ferulic acid methyl ester). The potential of the identified biomarkers to reconstruct vegetation composition is discussed according to their depth records in cores from six peatlands from boreal, temperate and tropical biomes. The occurrence of markers for Sphagnum, graminoids and lichens in all six studied peat deposits indicates that they persist in peat of thousands of years old, in different vegetation types and under different conditions. In order to facilitate the quantification of biomarkers from pyrolysates, typically expressed as proportion (%) of the total quantified pyrolysis products, an internal standard (5-α-androstane) was introduced. Depth records of the Sphagnum marker 4-isopropenylphenol from the upper 3 m of a Sphagnum-dominated peat, from samples analysed with and without internal standard showed a strong positive correlation (r2 = 0.72, P < 0.0005, n = 12). This indicates that application of an internal standard is a reliable method to assess biomarker depth records, which enormously facilitates the use of analytical pyrolysis in biomarker research by avoiding quantification of a high number of products.

Recycling of phenolic compounds in Borneo's tropical peat swamp forests.

PubMed

Yule, Catherine M; Lim, Yau Yan; Lim, Tse Yuen

2018-02-07

Tropical peat swamp forests (TPSF) are globally significant carbon stores, sequestering carbon mainly as phenolic polymers and phenolic compounds (particularly as lignin and its derivatives) in peat layers, in plants, and in the acidic blackwaters. Previous studies show that TPSF plants have particularly high levels of phenolic compounds which inhibit the decomposition of organic matter and thus promote peat accumulation. The studies of phenolic compounds are thus crucial to further understand how TPSF function with respect to carbon sequestration. Here we present a study of cycling of phenolic compounds in five forests in Borneo differing in flooding and acidity, leaching of phenolic compounds from senescent Macaranga pruinosa leaves, and absorption of phenolics by M. pruinosa seedlings. The results of the study show that total phenolic content (TPC) in soil and leaves of three species of Macaranga were highest in TPSF followed by freshwater swamp forest and flooded limestone forest, then dry land sites. Highest TPC values were associated with acidity (in TPSF) and waterlogging (in flooded forests). Moreover, phenolic compounds are rapidly leached from fallen senescent leaves, and could be reabsorbed by tree roots and converted into more complex phenolics within the leaves. Extreme conditions-waterlogging and acidity-may facilitate uptake and synthesis of protective phenolic compounds which are essential for impeded decomposition of organic matter in TPSF. Conversely, the ongoing drainage and degradation of TPSF, particularly for conversion to oil palm plantations, reverses the conditions necessary for peat accretion and carbon sequestration.

Revealing spatial distribution of soil organic carbon contents and stocks of a disturbed bog relict by in-situ NIR and apparent EC mapping

NASA Astrophysics Data System (ADS)

Bechtold, Michel; Tiemeyer, Bärbel; Don, Axel; Altdorff, Daniel; van der Kruk, Jan; Huisman, Johan A.

2013-04-01

Previous studies showed that in-situ visible near-infrared (vis-NIR) spectroscopy can overcome the limitations of conventional soil sampling. Costs can be reduced and spatial resolution enhanced when mapping field-scale variability of soil organic carbon (SOC). Detailed maps can help to improve SOC management and lead to better estimates of field-scale total carbon stocks. Knowledge of SOC field patterns may also help to reveal processes and factors controlling SOC variability. In this study, we apply in situ vis-NIR and apparent electrical conductivity (ECa) mapping to a disturbed bog relict. The major question of this application study was how field-scale in-situ vis-NIR mapping performs for a very heterogeneous area and under difficult grassland conditions and under highly-variable water content conditions. Past intensive peat cutting and deep ploughing in some areas, in combination with a high background heterogeneity of the underlying mineral sediments, have led to a high variability of SOC content (5.6 to 41.3 %), peat layer thickness (25 to 60 cm) and peat degradation states (from nearly fresh to amorphous). Using a field system developed by Veris Technologies (Salina KS, USA), we continuously collected vis-NIR spectra at 10 cm depth (measurement range: 350 nm to 2200 nm) over an area of around 12 ha with a line spacing of about 12 m. The system includes a set of discs for measuring ECa of the first 30 and 90 cm of the soil. The same area was also mapped with a non-invasive electro-magnetic induction (EMI) setup that provided ECa data of the first 25, 50 and 100 cm. For calibration and validation of the spatial data, we took 30 representative soil samples and 15 soil cores of about 90 cm depth, for which peat thickness, water content, pore water EC, bulk density (BD), as well as C and N content were determined for various depths. Preliminary results of the calibration of the NIR spectra to the near-surface SOC contents indicate good data quality despite the challenging site conditions. Bore hole data indicates that the peat layer is characterized by lower BD, higher pore water EC, higher SOC content, and higher water contents compared to the underlying mineral sediments. This ECa contrast at the peat-sand interface is promising for using the various ECa investigation depths as predictors for peat thickness. Preliminary EMI results also show a correlation between ECa and SOC content, most strongly for the 25 cm EMI signal. We evaluate how vis-NIR and ECa data can be used in a joined approach to estimate SOC content as well as SOC stock distribution.

Late-Holocene environmental and climatic changes in central part of the Western Sayan Mountain

NASA Astrophysics Data System (ADS)

Grenaderova, Anna; Sharafutdinov, Ruslan

2016-04-01

The purpose of this collaborative research is to determine how Holocene climate variability affects the landscapes evolution in valley of Buyba River. The work was conducted at the intersection of three disciplines: paleobotany, mineralogy and geochemistry. Data about environmental and climate changes in the Late Holocene in central part of Western Sayan are presented. We analyzed four peatland locations that, related to a single area of the river catchment. Sediment cores were taken from the central part of the peatland landscape. The age was determined by radiocarbon dating. Start of bog forming occurred asynchronously within the northern macroslope of Western Sayan. Bogs age decreases with the increase in the absolute elevations. On the highest elevation of 1656 m, the process of peat accumulation started 460 ± 80 years ago, after a significant reduction of snowfields. The most ancient peat layers formed at the altitude of 1320 meters and in elevations down the slope, and were aged 2950 ± 110 years or more (up to 5000 years). Over the period from 5000 to 4000 years ago, there were dryer and warmer climate conditions in the research area. Slopes of trough valleys were covered with sub-alpine shrubs of dwarf birch and alder, tree layer was absent. According to the pollen analysis, the role of tree vegetation (Pinus forest with participation of Pinus sibirica and Betula sect. Albae) was larger at the foothills. At the same time, at an altitude of 1650 m peat deposits are not formed, only isolated remains of plant detritus were found in much younger gravelly-clay sediments. Shallow flowing pond conditions were characteristic for stages before peat accumulation . Geochemical analysis of the ratio Th / U in loam, underlying peat, allows one to infer about oxidizing conditions during sedimentation. Analysis of the minerals in the peat layer, and the dynamics of accumulation of Na, Al, Ti (INAA-method) indicate that the time interval 500-2200 years was characterized with most stable hydrological conditions. During this period, the flood waters have supplied the least amount of allochthonous contaminants on the surface of the swamp. On the peatlands, sedge and sedge-moss plant communities were developed. Main plant species which grows in the peatlands are Carex altaica (Gorodk.) V.Krecz, Carex limosa L. Tomentypnum nitens Hedw., Aulacomnium palustre (Hedw.) Schwaegr., Warnstorfia exannulata (B.S.G.) Loeske., Thelypteris palustris Schott, Baeothryon caespitosum (L.) A.Dietr. During the last 500 years an increase of allochthonous contaminants inputs to marsh sediments is observed. In our opinion, the main causes of the increase were reduction the forest area, sharper contrast of summer and winter temperatures and more rapid melting of snow in early summer. The last cause lead to increased levels of floods. Eutrophic-mesotrophic sphagnum communities (Sphagnum warnstorfii Russ., Sph.subsecundum Nees,, Sphagnum angustifolium Jensen., Sph. fuscum (Schimp.) Klinggr.), which are growing at the moment, begin to develop in the peatlands since 500 years ago.

Spatial variability of active layer thickness detected by ground-penetrating radar in the Qilian Mountains, Western China

NASA Astrophysics Data System (ADS)

Cao, Bin; Gruber, Stephan; Zhang, Tingjun; Li, Lili; Peng, Xiaoqing; Wang, Kang; Zheng, Lei; Shao, Wanwan; Guo, Hong

2017-03-01

The active layer plays a key role in geomorphic, hydrologic, and biogeochemical processes in permafrost regions. We conducted a systematic investigation of active layer thickness (ALT) in northeastern Qinghai-Tibetan Plateau by using ground-penetrating radar (GPR) with 100 and 200 MHz antennas. We used mechanical probing, pit, and soil temperature profiles for evaluating ALT derived from GPR. The results showed that GPR is competent for detecting ALT, and the error was ±0.08 m at common midpoint co-located sites. Considerable spatial variability of ALT owing to variation in elevation, peat thickness, and slope aspect was found. The mean ALT was 1.32 ± 0.29 m with a range from 0.81 to 2.1 m in Eboling Mountain. In Yeniu Gou, mean ALT was 2.72 ± 0.88 m and varied from 1.07 m on the north-facing slope to 4.86 m around the area near the lower boundary of permafrost. ALT in peat decreased with increasing elevation at rates of -1.31 m/km (Eboling Mountain) and -2.1 m/km (Yeniu Gou), and in mineral soil in Yeniu Gou, the rate changed to -4.18 m/km. At the same elevation, ALT on the south-facing slope was about 0.8 m thicker than that on the north-facing slopes, while the difference was only 0.18 m in peat-covered area. Within a 100 m2 area with a local elevation difference of 0.8 m, ALT varied from 0.68 m to 1.25 m. Both field monitoring and modeling studies on spatial ALT variations require rethinking of the current strategy and comprehensive design.

Cone Penetration Testing, a new approach to quantify coastal-deltaic land subsidence by peat consolidation

NASA Astrophysics Data System (ADS)

Koster, Kay; Erkens, Gilles; Zwanenburg, Cor

2016-04-01

It is undisputed that land subsidence threatens coastal-deltaic lowlands all over the world. Any loss of elevation (on top of sea level rise) increases flood risk in these lowlands, and differential subsidence may cause damage to infrastructure and constructions. Many of these settings embed substantial amounts of peat, which is, due to its mechanically weak organic composition, one of the main drivers of subsidence. Peat is very susceptible to volume reduction by loading and drainage induced consolidation, which dissipates pore water, resulting in a tighter packing of the organic components. Often, the current state of consolidation of peat embedded within coastal-deltaic subsidence hotspots (e.g. Venice lagoon, Mississippi delta, San Joaquin delta, Kalimantan peatlands), is somewhere between its initial (natural) and maximum compressed stage. Quantifying the current state regarding peat volume loss, is of utmost importance to predict potential (near) future subsidence when draining or loading an area. The processes of subsidence often afflict large areas (>103 km2), thus demanding large datasets to assess the current state of the subsurface. In contrast to data describing the vertical motions of the actual surface (geodesy, satellite imagery), subsurface information applicable for subsidence analysis are often lacking in subsiding deltas. This calls for new initiatives to bridge that gap. Here we introduce Cone Penetration Testing (CPT) to quantify the amount of volume loss peat layers embedded within the Holland coastal plain (the Netherlands) experienced. CPT measures soil mechanical strength, and hundreds of thousands of CPTs are conducted each year on all continents. We analyzed 28 coupled CPT-borehole observations, and found strong empirical relations between volume loss and increased peat mechanical strength. The peat lost between ~20 - 95% of its initial thickness by dissipation of excess pore water. An increase in 0.1 - 0.4 MPa of peat strength is accountable for 20 - 75 % of the volume loss, and 0.4 - 0.7 MPa for 75 - 95 % volume loss. This indicates that large amounts of volume by water dissipation has to be lost, before peat experiences a serious increase in strength, which subsequently continuous to increase with only small amount of volume loss. To demonstrate the robustness of our approach to the international field of land subsidence, we applied the obtained empirical relations to previously published CPT logs deriving from the peat-rich San Joaquin-Sacramento delta and the Kalimantan peatlands, and found volume losses that correspond with previously published results. Furthermore, we used the obtained results to predict maximum surface lowering for these areas by consolidation. In conclusion, these promising results and its worldwide popularity yielding large datasets, open the door for CPT as a generic method to contribute to quantifying the imminent threat of coastal-deltaic land subsidence.

Effects of peatland drainage on water quality: a case study of the shallow blanket bogs of Exmoor, UK

NASA Astrophysics Data System (ADS)

Grand-Clement, E.; Luscombe, D.; Le Feuvre, N.; Smith, D.; Anderson, K.; Brazier, R. E.

2012-04-01

Peatlands are widely represented in the South West of England (i.e. Exmoor, Dartmoor and Bodmin moors), but their existence is currently under threat due to both climate change and the impact of historical human activities. Peat cutting and intensive drainage for agricultural reclamation in the 19th and 20th century, have modified the hydrological behaviour of these shallow peats and dried out the upper layers, causing oxidation, erosion and vegetation change. Such anthropogenic impacts directly affect the storage of carbon, but also the provision of other ecosystem services, such as the supply of drinking water, and the support of specific and rare habitats. Blocking drainage ditches to restore the hydrological behaviour of peatlands has mostly been undertaken in the North of England, but to date, little is still known about the consequences of such management approaches on the overall Carbon stocks. The need to monitor restoration of peatlands in the South West of England arises due to the specific characteristics of the peat - it is often shallower than more northerly peat and dominated by Purple Moor Grass. In addition, and in part because of the shallowness of the resource, the peat has been damaged differently, often with very dense networks of hand-cut ditches which behave as highly efficient drainage networks. Most importantly, their location at the southernmost margin of the UK peatlands' geographical extent makes them extremely vulnerable to climate change, and so it is hypothesised that monitoring of these peatlands may provide an 'early warning system' for climatic impacts that affect more northerly sites in years to come. This study focuses upon the current impact of peatland degradation on water quality on Exmoor. Our experimental approach employs detailed, high resolution monitoring of selected ditches that are representative of damaged conditions on Exmoor, from small- (30 x 30cm ditches) through medium- (50x50cm), large- (1-2m ditches) and finally headwater catchment-scales. Flow monitoring has been in place at all scales since November 2010. Flow proportional water samples were collected during a range of events throughout winter 2011-2012 and analysed for Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC), pH and colour. These variables were identified as critical, both in terms of carbon cycling and for costly water treatment that currently takes place downstream. Results were examined spatially in relation to drain sizes and magnitude/frequency of event, to improve our understanding of carbon losses in streams from damaged peatlands and further estimate the potential for improvement that can be expected after restoration. Data presented here focus on the DOC and colour and demonstrate the importance of understanding across different scales of ditch and understanding the effects of the magnitude/frequency of events that are observed prior to restoration of the system.

Seasonally frozen layer in natural and drained peatlands at the South of West Siberia, Russia

NASA Astrophysics Data System (ADS)

Dyukarev, Egor; Kiselev, Maxim; Voropay, Nadezhda; Preis, Yulia

2017-04-01

The temperature regime of soils in natural and drained peatlands at Bakchar bog located in the South Taiga zone of West Siberia is studied. Soil temperature for depths up to 320 cm was registered using autonomous temperature profile recorder during the period from August 2010 to September 2016. Maximal and minimal temperatures were registered at surface in July and February, consequently. Extreme soil temperatures at 320 cm depth shifts to December (maximum) and July (minimum) reducing absolute values. Annual peat soil temperature amplitude decrease with depth from 21,8 °C on surface to 1,1 °C at 320 cm. The analysis of daily, month and annual mean data of temperature in peat soil has shown that seasonally frozen layer was registered up to 20-60 cm depth. The duration of seasonally freeze layer existence varies from 130 to 180 days. Drained peatlands with the lowest water table have highest freeze depth. Soil at water-logged sedge-sphagnum fen in winter is warmer than soil in ryam ecosystem and mineral soil at upland. Maximal freezing depth in peatlands is up to 3 times lower than at drain areas.

Phenol oxidase activity in secondary transformed peat-moorsh soils

NASA Astrophysics Data System (ADS)

Styła, K.; Szajdak, L.

2009-04-01

The chemical composition of peat depends on the geobotanical conditions of its formation and on the depth of sampling. The evolution of hydrogenic peat soils is closely related to the genesis of peat and to the changes in water conditions. Due to a number of factors including oscillation of ground water level, different redox potential, changes of aerobic conditions, different plant communities, and root exudes, and products of the degradation of plant remains, peat-moorsh soils may undergo a process of secondary transformation conditions (Sokolowska et al. 2005; Szajdak et al. 2007). Phenol oxidase is one of the few enzymes able to degrade recalcitrant phenolic materials as lignin (Freeman et al. 2004). Phenol oxidase enzymes catalyze polyphenol oxidation in the presence of oxygen (O2) by removing phenolic hydrogen or hydrogenes to from radicals or quinines. These products undergo nucleophilic addition reactions in the presence or absence of free - NH2 group with the eventual production of humic acid-like polymers. The presence of phenol oxidase in soil environments is important in the formation of humic substances a desirable process because the carbon is stored in a stable form (Matocha et al. 2004). The investigations were carried out on the transect of peatland 4.5 km long, located in the Agroecological Landscape Park host D. Chlapowski in Turew (40 km South-West of Poznań, West Polish Lowland). The sites of investigation were located along Wyskoć ditch. The following material was taken from four chosen sites marked as Zbechy, Bridge, Shelterbelt and Hirudo in two layers: cartel (0-50cm) and cattle (50-100cm). The object of this study was to characterize the biochemical properties by the determination of the phenol oxidize activity in two layers of the four different peat-moors soils used as meadow. The phenol oxidase activity was determined spectrophotometrically by measuring quinone formation at λmax=525 nm with catechol as substrate by method of Perucci et al. (2000). In peat the highest activities of phenol oxidase was observed in the combinations marked as Shelterbelt and whereas the lowest - in Zbechy, Bridge and Hirudo. Activities of this enzyme in peat ranged from 15.35 to 38.33 μmol h-1g d.m soil. Increased activities of phenol oxidase have been recorded on the depth 50-100cm - catotelm (21.74-38.33 μmol h-1g d.m soil) in comparison with the depth 0-50cm - acrotelm (15.35-28.32 μmol h-1g d.m soil). References Freeman, C., Ostle N.J., Fener, N., Kang H. 2004. A regulatory role for phenol oxidase during decomposition in peatlands. Soil Biology and Biochemistry, 36, 1663-1667. Matocha Ch.J., Haszler G.R., Grove J.H. 2004. Nitrogen fertilization suppresses soil phenol oxidase enzyme activity in no-tillage systems. Soil Science, 169/10, 708-714. Perucci P., Casucci C., Dumontet S. 2000. An improved method to evaluate the o-diphenol oxidase activity of soil. Soil Biology and Biochemistry, 32, 1927-1933. Sokolowska Z., Szajdak L., Matyka-Sarzyńska D. 2005. Impact of the degree of secondary transformation on amid-base properties of organic compounds in mucks. Geoderma, 127, 80-90. Szajdak L., Szczepański M., Bogacz A. 2007. Impact of secondary transformation of peat-moorsh soils on the decrease of nitrogen and carbon compounds in ground water. Agronomy Research, 5/2, 189-200.

Fine-root growth in a forested bog is seasonally dynamic, but shallowly distributed in nutrient-poor peat

DOE PAGES

Iversen, Colleen M.; Childs, Joanne; Norby, Richard J.; ...

2017-03-30

Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. Here, we aimed to determine how the amount and timing of fine-root growth in a forested, ombrotrophic bog varied across gradients of vegetation density, peat microtopography, and changes in environmental conditions across the growing season and throughout the peat profile. We quantified fine-root peak standing crop and growth using non-destructive minirhizotron technology over a two-year period, focusing on the dominant woody species in the bog: Picea mariana, Larix laricina, Rhododendron groenlandicum, and Chamaedaphne calyculata. The fine roots ofmore » trees and shrubs were concentrated in raised hummock microtopography, with more tree roots associated with greater tree densities and a unimodal peak in shrub roots at intermediate tree densities. Fine-root growth tended to be seasonally dynamic, but shallowly distributed, in a thin layer of nutrient-poor, aerobic peat above the growing season water table level. Finally, the dynamics and distribution of fine roots in this forested ombrotrophic bog varied across space and time in response to biological, edaphic, and climatic conditions, and we expect these relationships to be sensitive to projected environmental changes in northern peatlands.« less

INNOVATIVE TECHNOLOGY EVALUATION REPORT ...

EPA Pesticide Factsheets

The Russian Peat Borer designed and fabricated by Aquatic Research Instruments was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation Program in April and May 1999 at sites in EPA Regions 1 and 5, respectively. In addition to assessing ease of sampler operation, key objectives of the demonstration included evaluating the sampler?s ability to (1) consistently collect a given volume of sediment, (2) consistently collect sediment in a given depth interval, (3) collect samples with consistent characteristics from a homogenous layer of sediment, and (4) collect samples under a variety of site conditions. This report describes the demonstration results for the Russian Peat Borer and two conventional samplers (the Hand Corer and Vibrocorer) used as reference samplers. During the demonstration, the Russian Peat Borer was the only sampler that collected samples in the deep depth interval (4 to 11 feet below sediment surface). It collected representative and relatively uncompressed core samples of consolidated sediment in discrete depth intervals. The reference samplers collected relatively compressed samples of both consolidated and unconsolidated sediments from the sediment surface downward; sample representativeness may be questionable because of core shortening and core compression. Sediment stratification was preserved only for consolidated sediment samples collected by the Russian Peat Borer but for bo

Re-assessing the vertical distribution of testate amoeba communities in surface peats: Implications for palaeohydrological studies.

PubMed

Roe, Helen M; Elliott, Suzanne M; Patterson, R Timothy

2017-08-01

Testate amoeba-derived transfer functions are frequently used in peatland palaeohydrological studies and involve the development of training sets from surficial peats. However, within acrotelmic peats, considerable vertical variation in assemblage composition can occur, particularly along Sphagnum stems, which may limit the representation of the associated 'contemporary' testate amoeba samples as analogues for the peatland surface. This paper presents contiguous testate amoeba assemblage data from nine monoliths collected from different peatland microforms (hummock, hollow, lawn) in three Sphagnum dominated ombrotrophic peatlands in Ontario and Quebec, eastern Canada. The aim is to: (i) gain a greater understanding of the vertical distribution of xerophilous/hygrophilous taxa along Sphagnum stems; (ii) determine the vertical extent of live/encysted taxa along this gradient; and (iii) assess the significance of this distribution on surface sampling protocols. The results show that testate amoeba communities in the uppermost acrotelmic peat layers display considerable variability. This may reflect a complex interplay of abiotic and biotic controls, including moisture, temperature, light and other characteristics, food availability, and mineral particle availability for test construction. These findings underline the complexity of testate amoeba community structure and highlight the importance of analysing both living and dead Sphagnum stem sections when developing calibration sets. Copyright © 2017 Elsevier GmbH. All rights reserved.

Fine-root growth in a forested bog is seasonally dynamic, but shallowly distributed in nutrient-poor peat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iversen, Colleen M.; Childs, Joanne; Norby, Richard J.

Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. Here, we aimed to determine how the amount and timing of fine-root growth in a forested, ombrotrophic bog varied across gradients of vegetation density, peat microtopography, and changes in environmental conditions across the growing season and throughout the peat profile. We quantified fine-root peak standing crop and growth using non-destructive minirhizotron technology over a two-year period, focusing on the dominant woody species in the bog: Picea mariana, Larix laricina, Rhododendron groenlandicum, and Chamaedaphne calyculata. The fine roots ofmore » trees and shrubs were concentrated in raised hummock microtopography, with more tree roots associated with greater tree densities and a unimodal peak in shrub roots at intermediate tree densities. Fine-root growth tended to be seasonally dynamic, but shallowly distributed, in a thin layer of nutrient-poor, aerobic peat above the growing season water table level. Finally, the dynamics and distribution of fine roots in this forested ombrotrophic bog varied across space and time in response to biological, edaphic, and climatic conditions, and we expect these relationships to be sensitive to projected environmental changes in northern peatlands.« less

Controls on methane released through ebullition in peatlands affected by permafrost degradation

USGS Publications Warehouse

Klapstein, Sara J.; Turetsky, Merritt R.; McGuire, A. David; Harden, Jennifer W.; Czimczik, C.I.; Xu, Xiaomei; Chanton, J.P.; Waddington, James Michael

2014-01-01

Permafrost thaw in peat plateaus leads to the flooding of surface soils and the formation of collapse scar bogs, which have the potential to be large emitters of methane (CH4) from surface peat as well as deeper, previously frozen, permafrost carbon (C). We used a network of bubble traps, permanently installed 20 cm and 60 cm beneath the moss surface, to examine controls on ebullition from three collapse bogs in interior Alaska. Overall, ebullition was dominated by episodic events that were associated with changes in atmospheric pressure, and ebullition was mainly a surface process regulated by both seasonal ice dynamics and plant phenology. The majority (>90%) of ebullition occurred in surface peat layers, with little bubble production in deeper peat. During periods of peak plant biomass, bubbles contained acetate-derived CH4 dominated (>90%) by modern C fixed from the atmosphere following permafrost thaw. Post-senescence, the contribution of CH4 derived from thawing permafrost C was more variable and accounted for up to 22% (on average 7%), in the most recently thawed site. Thus, the formation of thermokarst features resulting from permafrost thaw in peatlands stimulates ebullition and CH4 release both by creating flooded surface conditions conducive to CH4 production and bubbling as well as by exposing thawing permafrost C to mineralization.

Potential compensation of hydrological extremes in headwaters: case study of upper Vltava River basin, Šumava Mts., Czechia

NASA Astrophysics Data System (ADS)

Kocum, Jan; Janský, Bohumír.; Česák, Julius

2010-05-01

Increasing frequency of catastrophic flash floods and extreme droughts in recent years results in an urgent need of solving of flood protection questions and measures leading to discharge increase in dry periods. Flattening of discharge call for the use of untraditional practices as a suitable complement to classical engineering methods. These measures could be represented by gradual increase of river catchment retention capacity in headstream areas. Very favorable conditions for this research solution are concentrated to the upper part of Otava River basin (Vltava River left tributary, Šumava Mts., southwestern Czechia) representing the core zone of a number of extreme floods in Central Europe and the area with high peat land proportion. A number of automatic ultrasound and hydrostatic pressure water level gauges, climatic stations and precipitation gauges and utilization of modern equipment and methods were used in chosen experimental catchments to assess the landscape retention potential and to find out rainfall-runoff relations in this area. Successively, the detailed analysis of peat land hydrological function was carried out. The peat bogs influence on runoff conditions were assessed by thorough comparison of runoff regimes in subcatchments with different peat land proportion. The peat bog influence on hydrological process can be considered also with respect to its affecting of water quality. Therefore, hydrological monitoring was completed by ion, carbon (TOC) and oxygen isotopes balance observing within periods of high or low discharges in order to precise runoff phases separation by means of anion deficiency. Pedological survey of different soil types and textures was carried out to precise the estimation of its water capacity. Detailed analyses of extreme runoff ascending and descending phases and minimum discharges in profiles closing several subcatchments with different physical-geographic conditions show higher peak flow frequency and their shorter reaction to causal amount of precipitation in the case of highly peaty areas, therefore more distinct runoff variability of streams draining peat land localities. These findings were affirmed by geochemical approach laboratory outcomes within the meaning of significant contribution of runoff from peat lands to the total runoff during extreme flood situations. An important component of rainfall-runoff process in source areas of czech rivers represented by snow conditions was analyses very in detail by means of monitoring of snow cover height and its water equivalent in chosen experimental catchments. Outcomes of this study should markedly help with significant precising of estimation of water storage retained in a snow cover. Consecutive runoff simulations using mathematical techniques would then improve a hydrological forecast. In terms of present dyking of former channels draining peat land represented by so called peat bog revitalization partial findings refer to positive effect during mean runoff situations but their considerably negative influence on runoff process in cases of extremely high discharges. In order to achieve retention potential enhancement in source areas of czech rivers an evaluation of possible former accumulative reservoirs (used for wood floating in former times) restoration which could function for example as dry (green) polders should be considered. The system of such small storage bins could function as an alternative and supplement to greater dam reservoirs. Possible spaces for water retention are measured by geodetic total station and modelled by suitable methods in GIS software. Existing outcomes advert to the fact that the effectiveness of such reservoir system would not have to be neglecting. By implementation of these unforceable measures realized in river headstream areas it could be contributed to reduction of peak flows and to increase of water resources during extreme droughts in future.

Hydrothermal variations in soils resulting from the freezing and thawing processes in the active layer of an alpine grassland in the Qilian Mountains, northeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wang, Qingfeng; Yang, Qianqian; Guo, Hong; Xiao, Xiongxin; Jin, Huijun; Li, Lili; Zhang, Tingjun; Wu, Qingbai

2018-06-01

Soil hydrothermal dynamics, resulting from the freezing and thawing processes in the active layer and their influencing factors, were studied in the upper Heihe River Basin (UHRB) in the Qilian Mountains, northeastern Tibetan Plateau. Soil temperature and water content measurements were taken in the active layer of the UHRB in alpine grassland from 2013 to 2014. The results showed that the thaw rate of the active layer was significantly smaller in alpine paludal meadows than the thaw rate in alpine meadows and alpine steppes. This was mainly related to the hydrothermal properties of soils in the active layer, such as moisture content, thermal conductivity, and specific heat. During the thawing process, the active layer soil water content was higher and fluctuated less in alpine paludal meadows. Conversely, the soil water content was lower and fluctuated more significantly in alpine meadows and alpine steppes. These findings could be explained by the prevalence of peat soils, with a low bulk density, and high clay and organic matter content. By contrast, the soil particles in the active layer of alpine meadows and alpine steppes were significantly coarser, with higher bulk density and lower organic matter content. During the freezing process, gravel content and soil texture had a great impact on the unfrozen water content in the frozen soils. However, the factors influencing the soil water retention in frozen soils are complex, and further study is needed. These results provide theoretical support for the evaluation of the hydrological characteristics of the alpine permafrost zone in the Qilian Mountains. Furthermore, the effect of frozen ground on hydrological changes due to climate change in the Heihe River Basin can be simulated and predicted, providing a scientific basis for the ecological conservation of the Qilian Mountains National Park.

Use of hydraulic head to estimate volumetric gas content and ebullition flux in northern peatlands

USGS Publications Warehouse

Rosenberry, Donald O.; Glaser, Paul H.; Siegel, Donald I.; Weeks, Edwin P.

2003-01-01

Hydraulic head was overpressured at middepth in a 4.2‐m thick raised bog in the Glacial Lake Agassiz peatlands of northern Minnesota, and fluctuated in response to atmospheric pressure. Barometric efficiency (BE), determined by calculating ratios of change in hydraulic head to change in atmospheric pressure, ranged from 0.05 to 0.15 during July through November of both 1997 and 1998. The overpressuring and a BE response were caused by free‐phase gas contained primarily in the center of the peat column between two or more semielastic, semiconfining layers of more competent peat. Two methods were used to determine the volume of gas bubbles contained in the peat, one using the degree of overpressuring in the middepth of the peat, and the other relating BE to specific yield of the shallow peat. The volume of gas calculated from the overpressuring method averaged 9%, assuming that the gas was distributed over a 2‐m thick overpressured interval. The volume of gas using the BE method averaged 13%. Temporal changes in overpressuring and in BE indicate that the volume of gaseous‐phase gas also changed with time, most likely because of rapid degassing (ebullition) that allowed sudden loss of gas to the atmosphere. Estimates of gas released during the largest ebullition events ranged from 0.3 to 0.7 mol m−2 d−1. These ebullition events may contribute a significant source of methane and carbon dioxide to the atmosphere that has so far largely gone unmeasured by gas‐flux chambers or tower‐mounted sensors.

Terrestrial Responses to Variability in the Southern Westerlies Inferred from Deep Holocene Peat Archives

NASA Astrophysics Data System (ADS)

Hughes, P. D. M.; Mauquoy, D.; van Bellen, S.; Roland, T. P.; Loader, N.; Street-Perrott, F. A.; Daley, T.

2017-12-01

The deep ombrotrophic peat bogs of Chile are located throughout the latitudes dominated by the southern westerly wind belt. The domed surfaces of these peatlands make them sensitive to variability in summer atmospheric moisture balance and the near-continuous accumulation of deep peat strata throughout the Holocene to the present day means that these sites provide undisturbed archives of palaeoclimatic change. We have reconstructed late-Holocene bog water table depths - which can be related to changes in the regional balance of precipitation to evaporation (P-E) - from a suite of peat bogs located in three areas of Tierra del Feugo, Chile, under the main path of the SWWB. Water-table depths were reconstructed from sub-fossil testate amoebae assemblages using a conventional transfer function to infer past water-table depths, based on taxonomic classification of tests but also an innovative trait-based transfer function to infer the same parameter. Water table reconstructions derived from the two methods were consistent within sites. They show that mire water tables have been relatively stable in the last 2000 years across Tierra del Feugo. Higher water table levels, most probably indicating increased effective precipitation, were found between c. 1400 and 900 cal. BP., whereas a consistent drying trend was reconstructed across the region in the most recent peat strata. This shift may represent a pronounced regional decrease in precipitation and/or a change to warmer conditions linked to strengthening of the SWWB. However, other factors such as recent thinning of the ozone layer over Tierra del Fuego could have contributed to recent shifts in some testate amoebae species.

The Burning of Surface and Deep Peat during Boreal Forest and Peatland Fires: Implications for Fire Behaviour and Global Carbon Cycling

NASA Astrophysics Data System (ADS)

Turetsky, M. R.

2015-12-01

Fire is increasingly appreciated as a threat to peatlands and their carbon stocks. The global peatland carbon pool exceeds that of global vegetation and is similar to the current atmospheric carbon pool. Under pristine conditions, most of the peat carbon stock is protected from burning, and resistance to fire has increased peat carbon storage in high latitude regions over long time scales. This, in part, is due to the high porosity and storage coefficient of surface peat, which minimizes water table variability and maintains wet conditions even during drought. However, higher levels of disturbance associated with warming and increasing human activities are triggering state changes and the loss of resiliency in some peatland systems. This presentation will summarize information on burn area and severity in peatlands under undisturbed scenarios of hydrologic self-regulation, and will assess the consequences of warming and drying on peatland vegetation and wildfire behaviour. Our goal is to predict where and when peatlands will become more vulnerable to deep smouldering, given the importance of deep peat layers to global carbon cycling, permafrost stability, and a variety of other ecosystem services in northern regions. Results from two major wildfire seasons (2004 in Alaska and 2014 in the Northwest Territories) show that biomass burning in peatlands releases similar amounts of carbon to the atmosphere as patterns of burning in upland forests, but that peatlands are less vulnerable to severe burning that tends to occur in boreal forests during late season fire activity.

Biogeochemistry of aquatic humic substances in Thoreau's Bog, Concord, Massachusetts

USGS Publications Warehouse

McKnight, Diane M.; Thurman, E. Michael; Wershaw, Robert L.; Hemond, Herold

1985-01-01

Thoreau's Bog is an ombrotrophic floating—mat Sphagnum bog developed in a glacial kettlehole and surrounded by a red maple swamp. Concentrations of dissolved organic carbon in the porewater of the bog average 36 mg/L and are greatest near the surface, especially during late summer. This distribution suggest that the upper layer of living and dead Sphagnum and moderately humified peat is the major site of dissolved organic material production in the bog. The dissolved organic material consists mainly of aquatic fulvic acid (67%) and hydrophilic acids (20%); these organic acids control the pH (typically 4 or somewhat lower) of the bogwater. The elemental, amino acid, carbohydrate, and carboxylic acid contents of fulvic acid from the bog are similar to those of aquatic fulvic acid from the nearby Shawsheen River, although the phenolic hydroxyl content of fulvic acid from Thoreau's Bog is higher. The hydrophilic acids have greater amino acid, carbohydrate, and carboxylic acid contents than the fulvic acid, consistent with the hypothesis that hydrophilic acids are more labile intermediate compounds in the formation of fulvic acid.

What controls the oxidative ratio of UK peats? A multi-site study of elemental CHNO concentrations in peat cores

NASA Astrophysics Data System (ADS)

Clay, Gareth; Worrall, Fred; Masiello, Carrie

2013-04-01

The oxidative ratio (OR) is the amount of CO2 sequestered in the terrestrial biosphere for each mol of O2 produced. The OR governs the effectiveness of a terrestrial biome to mitigate the impact of anthropogenic CO2 emissions and it has been used to calculate the balance of terrestrial and oceanic carbon sinks across the globe. However, few studies have investigated the controls of the variability in OR. What factors affect OR - climate? Soil type? Vegetation type? N deposition? Land use? Land use change? Small shifts in OR could have important implications in the global partitioning of CO2 between the atmosphere, biosphere, and oceans. This study looks at peat soils from a series of sites representing a climatic transect across the UK. Duplicate peat cores were taken, along with samples of above-ground vegetation and litter, from sites in northern Scotland (Forsinard), southern Scotland (Auchencorth), northern England (Moor House; Thorne Moor) through the Welsh borders (Whixhall Moss) and Somerset levels (Westhay Moor) to Dartmoor and Bodmin Moor in the south west of England. Sub-samples of the cores were analysed for their CHNO concentrations using a Costech ECS 4010 Elemental combustion system. Using the method of Masiello et al. (2008), OR values could be calculated from these elemental concentrations. Results show that OR values of UK peats varied between 0.82 and 1.27 with a median value of 1.08 which is within the range of world soils. There were significant differences in OR of the peat between sites with the data falling into two broad groupings - Group 1: Forsinard, Auchencorth, Dartmoor and Bodmin Moor; Group 2: Moor House, Thorne Moor, Westhay Moor, Whixhall Moss. Whilst there were significant changes (p < 0.05) in elemental ratios with increasing peat depth (increasing C:N ratio and decreasing O:C ratio) there was no significant difference overall in OR with depth. This paper will explore some of the possible controlling factors on these ratios. Local vegetation was also sampled along with agricultural soils from the local area of the peat cores to compare the relative differences in different mediums. Significant differences (p < 0.01) between vegetation, agricultural soils and surface peat layers were found where vegetation had OR values of 1.03 ± 0.04 and agricultural soils had OR values of 1.15 ± 0.04. Further discussion of these results from these comparisons is also presented in this study.

UAV based 3D digital surface model to estimate paleolandscape in high mountainous environment

NASA Astrophysics Data System (ADS)

Mészáros, János; Árvai, Mátyás; Kohán, Balázs; Deák, Márton; Nagy, Balázs

2016-04-01

Our method to present current state of a peat bog was focused on the possible use of a UAV-system and later Structure-from-motion algorithms as processing technique. The peat bog site is located on the Vinderel Plateau, Farcǎu Massif, Maramures Mountains (Romania). The peat bog (1530 m a.s.l., N47°54'11", E24°26'37") lies below Rugasu ridge (c. 1820 m a.s.l.) and the locality serves as a conservation area for fallen down coniferous trees. Peat deposits were formed in a landslide concavity on the western slope of Farcǎu Massif. Nowadays the site is surrounded by a completely deforested landscape, and Farcǎu Massif lies above the depressed treeline. The peat bog has an extraordinary geomorphological situation, because a gully reached the bog and drained the water. In the recent past sedimentological and dendrochronological researches have been initiated. However, an accurate 3D digital surface model also needed for a complex paleoenvironmental research. Last autumn the bog and its surroundings were finally surveyed by a multirotor UAV developed in-house based on an open-source flight management unit and its firmware. During this survey a lightweight action camera (mainly to decrease payload weight) was used to take aerial photographs. While our quadcopter is capable to fly automatically on a predefined flight route, several over- and sidelapping flight lines were generated prior to the actual survey on the ground using a control software running on a notebook. Despite those precautions, limited number of batteries and severe weather affected our final flights, resulting a reduced surveyed area around peat bog. Later, during the processing we looked for a reliable tool which powerful enough to process more than 500 photos taken during flights. After testing several software Agisoft PhotoScan was used to create 3D point cloud and mesh about bog and its environment. Due to large number of photographs PhotoScan had to be configured for network processing to get reliable results and resolution. Based on the sediment layers of the peat bog together with the generated 3D surface model the paleoenvironment, the largest paleowater level can be reconstructed and we can estimate the dimension of the landslide which created the basin of the peat bog.

Age, extent and carbon storage of the central Congo Basin peatland complex.

PubMed

Dargie, Greta C; Lewis, Simon L; Lawson, Ian T; Mitchard, Edward T A; Page, Susan E; Bocko, Yannick E; Ifo, Suspense A

2017-02-02

Peatlands are carbon-rich ecosystems that cover just three per cent of Earth's land surface, but store one-third of soil carbon. Peat soils are formed by the build-up of partially decomposed organic matter under waterlogged anoxic conditions. Most peat is found in cool climatic regions where unimpeded decomposition is slower, but deposits are also found under some tropical swamp forests. Here we present field measurements from one of the world's most extensive regions of swamp forest, the Cuvette Centrale depression in the central Congo Basin. We find extensive peat deposits beneath the swamp forest vegetation (peat defined as material with an organic matter content of at least 65 per cent to a depth of at least 0.3 metres). Radiocarbon dates indicate that peat began accumulating from about 10,600 years ago, coincident with the onset of more humid conditions in central Africa at the beginning of the Holocene. The peatlands occupy large interfluvial basins, and seem to be largely rain-fed and ombrotrophic-like (of low nutrient status) systems. Although the peat layer is relatively shallow (with a maximum depth of 5.9 metres and a median depth of 2.0 metres), by combining in situ and remotely sensed data, we estimate the area of peat to be approximately 145,500 square kilometres (95 per cent confidence interval of 131,900-156,400 square kilometres), making the Cuvette Centrale the most extensive peatland complex in the tropics. This area is more than five times the maximum possible area reported for the Congo Basin in a recent synthesis of pantropical peat extent. We estimate that the peatlands store approximately 30.6 petagrams (30.6 × 10 15  grams) of carbon belowground (95 per cent confidence interval of 6.3-46.8 petagrams of carbon)-a quantity that is similar to the above-ground carbon stocks of the tropical forests of the entire Congo Basin. Our result for the Cuvette Centrale increases the best estimate of global tropical peatland carbon stocks by 36 per cent, to 104.7 petagrams of carbon (minimum estimate of 69.6 petagrams of carbon; maximum estimate of 129.8 petagrams of carbon). This stored carbon is vulnerable to land-use change and any future reduction in precipitation.

Hydrology and hydraulics of treatment wetlands constructed on drained peatlands

NASA Astrophysics Data System (ADS)

Postila, Heini; Ronkanen, Anna-Kaisa; Kløve, Bjørn

2013-04-01

Treatment wetlands are globally used for wastewater purification purposes. In Finland, these wetlands are commonly peatland-based and are used to treat runoff from peat extraction sites and peatland forestry. Wetlands are also used for polishing municipal wastewaters and mining waters. In peat extraction the structures are usually called overland flow areas (OFAs), which are traditionally established on pristine peatlands. However, nowadays establishing of new peat extraction sites is guided to drained peatland areas due to the Finnish Peat Use Strategy, which leads difficulties to find undisturbed peatland area for OFA. Therefore treatment wetlands have had to construct also on drained peatland areas. In drained areas peat physical properties have changed due to oxidation and subsidence and the water flow pathways differs from OFAs flow patterns, which maybe have effect on purification results. Thus in the present study we aim to clarify the hydrology and hydraulic properties of treatment wetlands constructed on drained peatland areas. For this purposes, 20 treatment wetlands on drained peatland areas across Finland were detailed measured for peat hydraulic conductivity. In selected areas, runoff was continuously monitored, flow distribution at treatment areas was studied and water residence times measured with tracer tests using potassium iodide (KI). Generally, in the study areas, the ditches had been completely blocked, partly blocked e.g with peat dams or not blocked at all. The ditches were located partly parallel to the flow direction and partly perpendicular to it. The distribution of water to the wetlands has been implemented in many different ways e.g. by distribution ditch or by perforated pipes. Based on the results, in majority of the wetlands, the peat drainage has clearly affected the hydraulic properties of wetlands, but not on all sites. In more than half of the wetlands (12), the median hydraulic conductivity of peat drastically decreased at the depth below 20 cm (or 10 cm). Two site it decreased at the depth of 40 cm, and at five sites, it was high at all depth investigated (down to 60-70 cm). The outflow proportion to inflow varied from 20 % to 97 %, which means that the part of the water infiltrated into the groundwater. Evaporation can explain part of the observed reduced water flow especially in dense tree stands. More than half of the wetlands contained also dry areas, meaning that treatment wetlands constructed on drained area have problems with even water distribution to the wetland. Ditches are also potential preferential flow paths and the shortest observed residence time was less than one day, but a much longer residence time was also recorded. The water flow in these treatment wetlands consequently occur only at the surface layer (0-20 cm) of peat, not deeper, or in the ditches, which may have impact on water purification results.

Gaseous mercury fluxes in peatlands and the potential influence of climate change

NASA Astrophysics Data System (ADS)

Haynes, Kristine M.; Kane, Evan S.; Potvin, Lynette; Lilleskov, Erik A.; Kolka, Randall K.; Mitchell, Carl P. J.

2017-04-01

Climate change has the potential to significantly impact the stability of large stocks of mercury (Hg) stored in peatland systems due to increasing temperatures, altered water table regimes and subsequent shifts in vascular plant communities. However, the Hg exchange dynamics between the atmosphere and peatlands are not well understood. At the PEATcosm Mesocosm Facility in Houghton, Michigan, total gaseous Hg (TGM) fluxes were monitored in a subset of 1-m3 peat monoliths with altered water table positions (high and low) and vascular plant functional groups (sedge only, Ericaceae only or unmanipulated control) above the Sphagnum moss layer. At the SPRUCE bog in north-central Minnesota, TGM fluxes were measured from plots subjected to deep peat soil warming (up to +9 °C above ambient at a depth of 2 m). At PEATcosm, the strongest depositional trend was observed with the Low WT - sedge only treatment mesocosms with a mean TGM flux of -73.7 ± 6.3 ng m-2 d-1, likely due to shuttling of Hg to the peat at depth by aerenchymous tissues. The highest total leaf surface and tissue Hg concentrations were observed with the Ericaceae shrubs. A negative correlation between TGM flux and Ericaceae total leaf surface area suggests an influence of shrubs in controlling Hg exchange through stomatal uptake, surface sorption and potentially, peat shading. Surface peat total Hg concentrations are highest in treatments with greatest deposition suggesting deposition controls Hg accumulation in surface peat. Fluxes in the SPRUCE plots ranged from -45.9 ± 93.8 ng m-2 d-1 prior to the implementation of the deep warming treatments to -1.41 ± 27.1 ng m-2 d-1 once warming targets were achieved at depth and +10.2 ± 44.6 ng m-2 d-1 following prolonged deep soil warming. While these intervals did not differ significantly, a significant positive increase in the slope of the regression between flux and surface temperature was observed across the pre-treatment and warming periods. Shifts in vascular vegetation cover and peat warming as a result of climate change may significantly affect the dynamics of TGM fluxes between peatlands and the atmosphere.

River Export of Dissolved and Particulate Organic Carbon from Permafrost and Peat Deposits across the Siberian Arctic

NASA Astrophysics Data System (ADS)

Wild, B.; Andersson, A.; Bröder, L.; Vonk, J.; Hugelius, G.; McClelland, J. W.; Raymond, P. A.; Gustafsson, O.

2017-12-01

Permafrost and peat deposits of northern high latitudes store more than 1300 Pg of organic carbon. This carbon has been preserved for thousands of years by cold and moist conditions, but is now increasingly mobilized as temperatures rise. While part will be degraded to CO2 and CH4 and amplify global warming, part will be exported by rivers to the Arctic Ocean where it can be degraded or re-buried by sedimentation. We here use the four large Siberian rivers Ob, Yenisey, Lena, and Kolyma as natural integrators of carbon mobilization in their catchments. We apply isotope based source apportionments and Markov Chain Monte Carlo Simulations to quantify contributions of organic carbon from permafrost and peat deposits to organic carbon exported by these rivers. More specifically, we compare the 14C signatures of dissolved and particulate organic carbon (DOC, POC) sampled close to the river mouths with those of five potential carbon sources; (1) recent aquatic and (2) terrestrial primary production, (3) the active layer of permafrost soils, (4) deep Holocene deposits (including thermokarst and peat deposits) and (5) Ice Complex Deposits. 14C signatures of these endmembers were constrained based on extensive literature review. We estimate that the four rivers together exported 2.4-4.5 Tg organic carbon from permafrost and peat deposits per year. While total organic carbon export was dominated by DOC (90%), the export of organic carbon from permafrost and peat deposits was more equally distributed between DOC (56%) and POC (44%). Recent models predict that ca. 200 Pg carbon will be lost as CO2 or CH4 by 2100 (RCP8.5) from the circumarctic permafrost area, of which roughly a quarter is drained by the Ob, Yenisey, Lena, and Kolyma rivers. Our comparatively low estimates of river carbon export thus suggest limited transfer of organic carbon from permafrost and peat deposits to high latitude rivers, or its rapid degradation within rivers. Our findings highlight the importance of both DOC and POC, and its degradation, for the fate of carbon mobilized from high latitude deposits under global warming, and indicate a low potential for its stabilization in the Arctic Ocean.

Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota: Pore Water DOM composition in a peat bog

DOE PAGES

Tfaily, Malak M.; Wilson, Rachel M.; Cooper, William T.; ...

2018-01-29

Here, we characterized dissolved organic matter (DOM) composition throughout the peat column at the Marcell S1 forested bog in northern Minnesota and tested the hypothesis that redox oscillations associated with cycles of wetting and drying at the surface of the fluctuating water table correlate with increased carbon, sulfur, and nitrogen turn over. We found significant vertical stratification of DOM molecular composition and excitation-emission matrix parallel factor analysis components within the peat column. In particular, the intermediate depth zone (~ 50 cm) was identified as a zone where maximum decomposition and turnover is taking place. Surface DOM was dominated by inputsmore » from surface vegetation. The intermediate depth zone was an area of high organic matter reactivity and increased microbial activity with diagenetic formation of many unique compounds, among them polycyclic aromatic compounds that contain both nitrogen and sulfur heteroatoms. These compounds have been previously observed in coal-derived compounds and were assumed to be responsible for coal's biological activity. Biological processes triggered by redox oscillations taking place at the intermediate depth zone of the peat profile at the S1 bog are assumed to be responsible for the formation of these heteroatomic PACs in this system. Alternatively, these compounds could stem from black carbon and nitrogen derived from fires that have occurred at the site in the past. Surface and deep DOM exhibited more similar characteristics, compared to the intermediate depth zone, with the deep layer exhibiting greater input of microbially degraded organic matter than the surface suggesting that the entire peat profile consists of similar parent material at different degrees of decomposition and that lateral and vertical advection of pore water from the surface to the deeper horizons is responsible for such similarities. Lastly, our findings suggest that molecular composition of DOM in peatland pore water is dynamic and is a function of ecosystem activity, water table, redox oscillation, and pore water advection.« less

Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota: Pore Water DOM composition in a peat bog

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tfaily, Malak M.; Wilson, Rachel M.; Cooper, William T.

Here, we characterized dissolved organic matter (DOM) composition throughout the peat column at the Marcell S1 forested bog in northern Minnesota and tested the hypothesis that redox oscillations associated with cycles of wetting and drying at the surface of the fluctuating water table correlate with increased carbon, sulfur, and nitrogen turn over. We found significant vertical stratification of DOM molecular composition and excitation-emission matrix parallel factor analysis components within the peat column. In particular, the intermediate depth zone (~ 50 cm) was identified as a zone where maximum decomposition and turnover is taking place. Surface DOM was dominated by inputsmore » from surface vegetation. The intermediate depth zone was an area of high organic matter reactivity and increased microbial activity with diagenetic formation of many unique compounds, among them polycyclic aromatic compounds that contain both nitrogen and sulfur heteroatoms. These compounds have been previously observed in coal-derived compounds and were assumed to be responsible for coal's biological activity. Biological processes triggered by redox oscillations taking place at the intermediate depth zone of the peat profile at the S1 bog are assumed to be responsible for the formation of these heteroatomic PACs in this system. Alternatively, these compounds could stem from black carbon and nitrogen derived from fires that have occurred at the site in the past. Surface and deep DOM exhibited more similar characteristics, compared to the intermediate depth zone, with the deep layer exhibiting greater input of microbially degraded organic matter than the surface suggesting that the entire peat profile consists of similar parent material at different degrees of decomposition and that lateral and vertical advection of pore water from the surface to the deeper horizons is responsible for such similarities. Lastly, our findings suggest that molecular composition of DOM in peatland pore water is dynamic and is a function of ecosystem activity, water table, redox oscillation, and pore water advection.« less

Multi-method investigation of cushion peatlands (

NASA Astrophysics Data System (ADS)

Forbriger, M.; Schittek, K.; Höfle, B.; Siart, C.; Eitel, B.

2012-04-01

This study presents a multi-method and multi-proxy approach for palaeonvironmental investigations in the western andean cordillera of southern Peru (Lucanas province, 14° S) using cushion peatlands as terrestrial geoarchives. The region stretching between the Altiplano and the Peruvian desert in the lowland shares a long term settlement history, in which local cultures adapted to climate change in many different ways. Being one of the most outstanding human remains, the abri below Cerro Llamoca, 4.450 m a.s.l. in the uppermost ranges of the Llamoca peatland catchment area further reveals an occupation history of almost 10.000 years, as revealed by latest archaeological investigations. In remote and highly elevated regions such as the central Andes, cushion peatlands basically represent the only high resolution terrestrial archives suitable for geoarchaeological and palaeoenvironmental studies. Characterized by high accumulation rates, they ideally document environmental changes, particularly at small time intervals. Within the multidisciplinary project 'Andean Transect - Climate Sensitivity of pre-Columbian Man-Environment-Systems' several sediment cores with depths up to 11.5 m b.s. were recovered from the Llamoca peatland. Based on almost 100 AMS 14C-datings they provide a chronology of 8000 years and, thus, offer profound insights into climatic and environmental changes in the study area. While nearly homogeneous peat layers record stable environmental conditions, the heterogeneous granulometric composition of intercalated sediment layers documents several periods of intense geomorphodynamic activity. Due to high resolution geochemical analyses of peat layers (1 cm interval; humification degree, CNS measurements, XRF-scanning), the existence of slight and short-term trends of landscape development during these phases can be identified. Additional pollen, charred particles and plant macrofossil analyses confirm these findings and help reconstructing local vegetation history. High-resolution digital elevation models derived from terrestrial laser scanning (TLS) provide important input data for geomorphologic analyses on current geomorphic processes that can be transferred to former times. Detailed subsurface information obtained by geophysics (electrical resistivity tomography ERT) helped identify the most suitable sampling sites. Information about peat thickness, stratigraphy and depth to bedrock was combined with topographical elevation data, chronometrical outcomes and palaeoenvironmental parameters to generate subsurface models of the study site. The findings allow reconstructing and visualizing the ancient landscape and the stages of peat development, which coincide with pre-Columbian cultural eras.

Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota

NASA Astrophysics Data System (ADS)

Tfaily, Malak M.; Wilson, Rachel M.; Cooper, William T.; Kostka, Joel E.; Hanson, Paul; Chanton, Jeffrey P.

2018-02-01

We characterized dissolved organic matter (DOM) composition throughout the peat column at the Marcell S1 forested bog in northern Minnesota and tested the hypothesis that redox oscillations associated with cycles of wetting and drying at the surface of the fluctuating water table correlate with increased carbon, sulfur, and nitrogen turn over. We found significant vertical stratification of DOM molecular composition and excitation-emission matrix parallel factor analysis components within the peat column. In particular, the intermediate depth zone ( 50 cm) was identified as a zone where maximum decomposition and turnover is taking place. Surface DOM was dominated by inputs from surface vegetation. The intermediate depth zone was an area of high organic matter reactivity and increased microbial activity with diagenetic formation of many unique compounds, among them polycyclic aromatic compounds that contain both nitrogen and sulfur heteroatoms. These compounds have been previously observed in coal-derived compounds and were assumed to be responsible for coal's biological activity. Biological processes triggered by redox oscillations taking place at the intermediate depth zone of the peat profile at the S1 bog are assumed to be responsible for the formation of these heteroatomic PACs in this system. Alternatively, these compounds could stem from black carbon and nitrogen derived from fires that have occurred at the site in the past. Surface and deep DOM exhibited more similar characteristics, compared to the intermediate depth zone, with the deep layer exhibiting greater input of microbially degraded organic matter than the surface suggesting that the entire peat profile consists of similar parent material at different degrees of decomposition and that lateral and vertical advection of pore water from the surface to the deeper horizons is responsible for such similarities. Our findings suggest that molecular composition of DOM in peatland pore water is dynamic and is a function of ecosystem activity, water table, redox oscillation, and pore water advection.

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

PubMed

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

2015-09-01

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

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

PubMed Central

Villanueva, Laura; Hopmans, Ellen C.; Rijpstra, W. Irene C.; Mets, Anchelique; Dedysh, Svetlana N.

2015-01-01

Northern wetlands make up a substantial terrestrial carbon sink and are often dominated by decay-resistant Sphagnum mosses. Recent studies have shown that planctomycetes appear to be involved in degradation of Sphagnum-derived debris. Novel trimethylornithine (TMO) lipids have recently been characterized as abundant lipids in various Sphagnum wetland planctomycete isolates, but their occurrence in the environment has not yet been confirmed. We applied a combined intact polar lipid (IPL) and molecular analysis of peat cores collected from two northern wetlands (Saxnäs Mosse [Sweden] and Obukhovskoye [Russia]) in order to investigate the preferred niche and abundance of TMO-producing planctomycetes. TMOs were present throughout the profiles of Sphagnum bogs, but their concentration peaked at the oxic/anoxic interface, which coincided with a maximum abundance of planctomycete-specific 16S rRNA gene sequences. The sequences detected at the oxic/anoxic interface were affiliated with the Isosphaera group, while sequences present in the anoxic peat layers were related to an uncultured planctomycete group. Pyrosequencing-based analysis identified Planctomycetes as the major bacterial group at the oxic/anoxic interface at the Obukhovskoye peat (54% of total 16S rRNA gene sequence reads), followed by Acidobacteria (19% reads), while in the Saxnäs Mosse peat, Acidobacteria were dominant (46%), and Planctomycetes contributed to 6% of the total reads. The detection of abundant TMO lipids in planctomycetes isolated from peat bogs and the lack of TMO production by cultures of acidobacteria suggest that planctomycetes are the producers of TMOs in peat bogs. The higher accumulation of TMOs at the oxic/anoxic interface and the change in the planctomycete community with depth suggest that these IPLs could be synthesized as a response to changing redox conditions at the oxic/anoxic interface. PMID:26150465

Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, Amrita; Schmidt, Michael P.; Stavitski, Eli

The speciation of iron (Fe) in organic matter (OM)-rich environments under in situ variable redox conditions is largely unresolved. Peatlands provide a natural setting to study Fe–OM interactions. Utilizing chemical, spectroscopic and theoretical modeling approaches, we report the chemical forms, oxidation states and local coordination environment of naturally occurring Fe in the vertically redox-stratified Manning peatlands of western New York. In addition, we report dominant carbon, sulfur and nitrogen species that can potentially stabilize the various Fe species present in these peatlands. Our results provide clear direct and indirect evidence for the co-occurrence of ferrous (Fe 2+) and ferric (Femore » 3+) iron species in peats under both oxic and anoxic conditions. Iron is mostly present within the operationally defined organic and amorphous (i.e., short range ordered, SRO) fractions; ferric iron primarily as magnetically isolated paramagnetic Fe 3+ in Fe(III)-organic complexes, but also in mineral forms such as ferrihydrite; ferrous iron in tetrahedral coordination in Fe(II)-organic complexes with minor contribution from pyrite. All of the Fe species identified stabilize Fe(III) and/or Fe(II) in anoxic and oxic peats. Fundamental differences are also observed in the relative proportion of C, S and N functionalities of OM in oxic and anoxic peats. Aromatic C=C, ester, phenol and anomeric C (R-O-C-O-R), as well as thiol, sulfide and heterocyclic N functionalities are more prevalent in anoxic peats. Collectively, our experimental evidence suggests iron forms coordination complexes with O-, S- and N-containing functional groups of OM. We posit the co-occurrence of organic and mineral forms of Fe(II) and Fe(III) in both oxic and anoxic peat layers results from dynamic complexation and hydrolysis-precipitation reactions that occur under variable redox conditions. In conclusion, our findings aid in understanding the crucial role OM plays in determining Fe species in soils and sediments.« less

Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates

DOE PAGES

Bhattacharyya, Amrita; Schmidt, Michael P.; Stavitski, Eli; ...

2017-10-31

The speciation of iron (Fe) in organic matter (OM)-rich environments under in situ variable redox conditions is largely unresolved. Peatlands provide a natural setting to study Fe–OM interactions. Utilizing chemical, spectroscopic and theoretical modeling approaches, we report the chemical forms, oxidation states and local coordination environment of naturally occurring Fe in the vertically redox-stratified Manning peatlands of western New York. In addition, we report dominant carbon, sulfur and nitrogen species that can potentially stabilize the various Fe species present in these peatlands. Our results provide clear direct and indirect evidence for the co-occurrence of ferrous (Fe 2+) and ferric (Femore » 3+) iron species in peats under both oxic and anoxic conditions. Iron is mostly present within the operationally defined organic and amorphous (i.e., short range ordered, SRO) fractions; ferric iron primarily as magnetically isolated paramagnetic Fe 3+ in Fe(III)-organic complexes, but also in mineral forms such as ferrihydrite; ferrous iron in tetrahedral coordination in Fe(II)-organic complexes with minor contribution from pyrite. All of the Fe species identified stabilize Fe(III) and/or Fe(II) in anoxic and oxic peats. Fundamental differences are also observed in the relative proportion of C, S and N functionalities of OM in oxic and anoxic peats. Aromatic C=C, ester, phenol and anomeric C (R-O-C-O-R), as well as thiol, sulfide and heterocyclic N functionalities are more prevalent in anoxic peats. Collectively, our experimental evidence suggests iron forms coordination complexes with O-, S- and N-containing functional groups of OM. We posit the co-occurrence of organic and mineral forms of Fe(II) and Fe(III) in both oxic and anoxic peat layers results from dynamic complexation and hydrolysis-precipitation reactions that occur under variable redox conditions. In conclusion, our findings aid in understanding the crucial role OM plays in determining Fe species in soils and sediments.« less

Mapping Soil Carbon in the Yukon Kuskokwim River Delta Alaska

NASA Astrophysics Data System (ADS)

Natali, S.; Fiske, G.; Schade, J. D.; Mann, P. J.; Holmes, R. M.; Ludwig, S.; Melton, S.; Sae-lim, N.; Jardine, L. E.; Navarro-Perez, E.

2017-12-01

Arctic river deltas are hotspots for carbon storage, occupying <1% of the pan-Arctic watershed but containing >10% of carbon stored in arctic permafrost. The Yukon Kuskokwim (YK) Delta, Alaska is located in the lower latitudinal range of the northern permafrost region in an area of relatively warm permafrost that is particularly vulnerable to warming climate. Active layer depths range from 50 cm on peat plateaus to >100 cm in wetland and aquatic ecosystems. The size of the soil organic carbon pool and vulnerability of the carbon in the YK Delta is a major unknown and is critically important as climate warming and increasing fire frequency may make this carbon vulnerable to transport to aquatic and marine systems and the atmosphere. To characterize the size and distribution of soil carbon pools in the YK Delta, we mapped the land cover of a 1910 km2 watershed located in a region of the YK Delta that was impacted by fire in 2015. The map product was the result of an unsupervised classification using the Weka K Means clustering algorithm implemented in Google's Earth Engine. Inputs to the classification were Worldview2 resolution optical imagery (1m), Arctic DEM (5m), and Sentinel 2 level 1C multispectral imagery, including NDVI, (10 m). We collected 100 soil cores (0-30 cm) from sites of different land cover and landscape position, including moist and dry peat plateaus, high and low intensity burned plateaus, fens, and drained lakes; 13 lake sediment cores (0-50 cm); and 20 surface permafrost cores (to 100 cm) from burned and unburned peat plateaus. Active layer and permafrost soils were analyzed for organic matter content, soil moisture content, and carbon and nitrogen pools (30 and 100 cm). Soil carbon content varied across the landscape; average carbon content values for lake sediments were 12% (5- 17% range), fens 26% (9-44%), unburned peat plateaus 41% (34-44%), burned peat plateaus 19% (7-34%). These values will be used to estimate soil carbon pools, which will be applied to the spatial extent of each landcover class in our map, yielding a watershed-wide and spatially explicit map of soil carbon in the YK Delta. This map will provide the basis for understanding where carbon is stored in the watershed and the vulnerability of that carbon to climate change and fire.

Inferring LGM sedimentary and climatic changes in the southern Eastern Alps foreland through the analysis of a 14C ages database (Brenta megafan, Italy)

NASA Astrophysics Data System (ADS)

Rossato, Sandro; Mozzi, Paolo

2016-09-01

The analysis of a database of radiocarbon ages is proposed as a tool for investigating major glaciofluvial systems of the Last Glacial Maximum (LGM) in the Alpine foreland, and their relations with glacier dynamics and climatic fluctuations. Our research concerns the Brenta megafan (NE Italy), where 110 radiocarbon dates integrate a robust regional stratigraphic and palaeoclimatic framework. Age-depth models allowed us to calculate sedimentation rates, while the time distribution of peat layers, which recurrently formed in this region during the LGM, were estimated through meta-analysis. The reliability of statistical results was carefully evaluated using Pearson and Spearman coefficients. Sedimentation rates in the Brenta megafan markedly fluctuated during LGM: ≈1.8 m/ka between 40 and 26.7 ka cal BP; ≈3 m/ka between 26.7 and 23.8 ka cal BP and ≈1.4 m/ka from 23.8 to 17.5 ka cal BP, when the distributary system deactivated due to fan-head trenching. This is evidence that sediment input and routing in the glaciofluvial distributary system was particularly efficient during the central part of LGM, when glaciers were stable at their outermost position. Meta-analysis indicates an increase in peat formation in correspondence with global (Heinrich Event 3 and/or the Greenland Interstadial 5.1 and 4 for the 30.5, 29.6 and 28.8 ka cal BP peaks) and regional (23.5 ka cal BP) wet events. Other peaks at 22.2, 21.8, 20.2 and 19 ka cal BP correlate with fluctuations of south-eastern Alpine glaciers. Significant peat formation continued until ≈18 ka cal BP, when the last peak occurred. A marked decrease in peat formation is recorded concomitantly with the onset of Heinrich Event 2 (i.e. the 26 ka cal BP trough). The good correspondence of sedimentary events in the Brenta glaciofluvial system with the dynamics of glaciers and glaciofluvial and lacustrine systems in the southern Eastern Alps suggests a common climatic forcing on the whole region during the LGM. Peat layer formation in the floodplain fens increased significantly in correspondence with glacier withdrawals and/or wetter climatic episodes, constituting a good proxy for climatic fluctuations during glacial periods. It also allows correlations across different continental environments and regions in the northern hemisphere.

Airborne Electromagnetic Mapping of Peatlands: a Case Study in Norway.

NASA Astrophysics Data System (ADS)

Silvestri, S.; Viezzoli, A.; Pfaffhuber, A. A.; Vettore, A.

2017-12-01

Peatlands are extraordinary reservoirs of organic carbon that can be found over a wide range of latitudes, in tropical, to temperate, to (sub)polar climates. According to some estimates, the carbon stored in peatlands almost match the atmospheric carbon pool. Peatlands degradation due to natural and anthropogenic factors releases every year large amount of CO2 and other green house gasses into the atmosphere. The conservation of peatlands is therefore a key measure to reduce emissions and to mitigate climate change. An effective plan to prevent peatlands degradation must move from a precise estimate of the volume of peat stored across vast territories around the world. One example are the several bogs that characterize large surfaces in Norway. Our research combines the use of high spatial resolution satellite optical data with Airborne Electromagnetic (AEM) and field measurements in order to map the extension and thickness of peat in Brøttum, Ringsaker province, Norway. The methodology allows us to quantify the volume of peat as well as the organic carbon stock. The variable thickness typical of Norwegian bogs allows us to test the limits of the AEM methodology in resolving near surface peat layers. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 747809. Start date: 1 June 2017. Duration: 24 months

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

PubMed

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

2014-11-04

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

Influence of vertical and lateral heat transfer on permafrost thaw, peatland landscape transition, and groundwater flow

USGS Publications Warehouse

Kurylyk, Barret L.; Masaki, Masaki; Quinton, William L.; McKenzie, Jeffrey M.; Voss, Clifford I.

2016-01-01

Recent climate change has reduced the spatial extent and thickness of permafrost in many discontinuous permafrost regions. Rapid permafrost thaw is producing distinct landscape changes in the Taiga Plains of the Northwest Territories, Canada. As permafrost bodies underlying forested peat plateaus shrink, the landscape slowly transitions into unforested wetlands. The expansion of wetlands has enhanced the hydrologic connectivity of many watersheds via new surface and near-surface flow paths, and increased streamflow has been observed. Furthermore, the decrease in forested peat plateaus results in a net loss of boreal forest and associated ecosystems. This study investigates fundamental processes that contribute to permafrost thaw by comparing observed and simulated thaw development and landscape transition of a peat plateau-wetland complex in the Northwest Territories, Canada from 1970 to 2012. Measured climate data are first used to drive surface energy balance simulations for the wetland and peat plateau. Near-surface soil temperatures simulated in the surface energy balance model are then applied as the upper boundary condition to a three-dimensional model of subsurface water flow and coupled energy transport with freeze-thaw. Simulation results demonstrate that lateral heat transfer, which is not considered in many permafrost models, can influence permafrost thaw rates. Furthermore, the simulations indicate that landscape evolution arising from permafrost thaw acts as a positive feedback mechanism that increases the energy absorbed at the land surface and produces additional permafrost thaw. The modeling results also demonstrate that flow rates in local groundwater flow systems may be enhanced by the degradation of isolated permafrost bodies.

Vulnerability of North American Boreal Peatlands to Interactions between Climate, Hydrology, and Wildland Fires

NASA Astrophysics Data System (ADS)

Bourgeau-Chavez, L. L.; Jenkins, L. K.; Kasischke, E. S.; Turetsky, M.; Benscoter, B.; Banda, E. J.; Boren, E. J.; Endres, S. L.; Billmire, M.

2013-12-01

North American boreal peatland sites of Alaska, Alberta Canada, and the southern limit of the boreal ecoregion (Michigan's Upper Peninsula) are the focus of an ongoing project to better understand the fire weather, hydrology, and climatic controls on boreal peatland fires. The overall goal of the research project is to reduce uncertainties of the role of northern high latitude ecosystems in the global carbon cycle and to improve carbon emission estimates from boreal fires. Boreal peatlands store tremendous reservoirs of soil carbon that are likely to become increasingly vulnerable to fire as climate change lowers water tables and exposes C-rich peat to burning. Increasing fire activity in peatlands could cause these ecosystems to become net sources of C to the atmosphere, which is likely to have large influences on atmospheric carbon concentrations through positive feedbacks that enhance climate warming. Remote sensing is key to monitoring, understanding and quantifying changes occurring in boreal peatlands. Remote sensing methods are being developed to: 1) map and classify peatland cover types; 2) characterize seasonal and inter-annual variations in the moisture content of surface peat (fuel) layers; 3) map the extent and seasonal timing of fires in peatlands; and 4) discriminate different levels of fuel consumption/burn severity in peat fires. A hybrid radar and optical infrared methodology has been developed to map peatland types (bog vs. fen) and level of biomass (open herbaceous, shrubby, forested). This methodology relies on multi-season data to detect phenological changes in hydrology which characterize the different ecosystem types. Landsat data are being used to discriminate burn severity classes in the peatland types using standard dNBR methods as well as individual bands. Cross referencing the peatland maps and burn severity maps will allow for assessment of the distribution of upland and peatland ecosystems affected by fire and quantitative analysis of emissions. Radar imagery from multiple platforms (L-band PALSAR, C-band ERS-2, Envisat, and Radarsat-2) is being used to develop soil moisture extraction algorithms to monitor changes (drying - wetting) through time and to develop a standard method for soil moisture assessment. Using data from the 1990s (ERS-1 and 2) through the present (Radarsat-2) will allow for determination of patterns of wetting and drying across the landscape. All the remote sensing analysis is supported with field work which has been coordinated with that of Canadian scientists. Field collection includes vegetation and hydrology data to validate peatland distribution maps, collection of water table depths and peat moisture content data to aid in algorithm development for radar organic soil moisture retrieval, and characterization of variations in depth of burning and carbon consumption during peatland fires to use in burn severity mapping and fire emissions modeling.

Thermal properties of degraded lowland peat-moorsh soils

NASA Astrophysics Data System (ADS)

Gnatowski, Tomasz

2016-04-01

Soil thermal properties, i.e.: specific heat capacity (c), thermal conductivity (K), volumetric heat capacity (C) govern the thermal environment and heat transport through the soil. Hence the precise knowledge and accurate predictions of these properties for peaty soils with high amount of organic matter are especially important for the proper forecasting of soil temperature and thus it may lead to a better assessment of the greenhouse gas emissions created by microbiological activity of the peatlands. The objective of the study was to develop the predictive models of the selected thermal parameters of peat-moorsh soils in terms of their potential applicability for forecasting changes of soil temperature in degraded ecosystems of the Middle Biebrza River Valley area. Evaluation of the soil thermal properties was conducted for the parameters: specific heat capacity (c), volumetric heat capacities of the dry and saturated soil (Cdry, Csat) and thermal conductivities of the dry and saturated soil (Kdry, Ksat). The thermal parameters were measured using the dual-needle probe (KD2-Pro) on soil samples collected from seven peaty soils, representing total 24 horizons. The surface layers were characterized by different degrees of advancement of soil degradation dependent on intensiveness of the cultivation practises (peaty and humic moorsh). The underlying soil layers contain peat deposits of different botanical composition (peat-moss, sedge-reed, reed and alder) and varying degrees of decomposition of the organic matter, from H1 to H7 (von Post scale). Based on the research results it has been shown that the specific heat capacity of the soils differs depending on the type of soil (type of moorsh and type of peat). The range of changes varied from 1276 J.kg-1.K-1 in the humic moorsh soil to 1944 J.kg-1.K-1 in the low decomposed sedge-moss peat. It has also been stated that in degraded peat soils with the increasing of the ash content in the soil the value of specific heat has decreased in a non-linear manner. Thermal parameters of the dry mass of the studied soils (Kdry, Cdry) were characterised by the mean value of approximately 0.11±0.028 W.m-1.K-1 and 0.781±0.220 MJ.m-3.K-1. The application of the correlation analysis showed that the most significant predictor of these properties of soils is the soil bulk density which, respectively explains: 54.6% and 67.1% of their variation. The increase of the accuracy in determining Kdry and Cdry was obtained by developing regression models, which apart from the bulk density also include the chemical properties of the peat soils. In the fully saturated soil the Ksat value ranged from 0.47 to 0.63 W.m-1.K-1, and the Csat varied from 3.200 to 3.995 MJ.m-3.K-1. The variation coefficients of these soil thermal features are at the level of approx. 5%. The obtained results allowed to conclude that the significant diversity of studied soils doesn't cause the significant differences in thermal soil parameters in fully saturated soils. The developed statistical relationships indicate that parameters Ksat and Csat were poorly correlated with saturated moisture content.

Impact of prescribed and repeated vegetation burning on blanket peat hydrology

NASA Astrophysics Data System (ADS)

Holden, Joseph; Brown, Lee; Palmer, Sheila; Johnston, Kerrylyn; Wearing, Catherine; Irvine, Brian

2013-04-01

In some peatlands there has been a tradition over the past century of burning vegetation to manage the landscape for a range of purposes. These include producing an environment suitable for game birds used in the gun sports industry and reducing the biomass fuel load to reduce possible wildfire damage to the peat. However, there have been few studies that have interrogated the impacts of this activity on peatland hydrological processes both at the plot scale and at the catchment scale. The EMBER project measured water tables, overland flow, hydraulic conductivity, stream discharge, and a myriad of aquatic invertebrate and peat physical and water chemistry indicators (at plot and stream scale) in ten upland blanket peat catchments in the UK. Five catchments were subject to a history of prescribed rotational patch burning with burning taking place each year over a proportion of the catchment (typically 5-10 %) but where for an individual patch the interval was typically 10-20 years. The other five catchments acted as controls which were not subject to burning, nor confounded by other detrimental activities such as drainage or forestry. Stream flows were flashier in response to rainfall in the catchments with prescribed burning patches and had greater rainfall to runoff efficiencies. Water tables were found to be significantly shallower with a smaller interquartile range for unburnt catchments. In the burnt catchments, more recently burnt plots had significantly greater mean water table depths and water table residence times were much less frequent within the upper 10 cm of the peat profile compared to plots that been burned more than a decade before. The water table residence curves will be explored in the presentation. The occurrence of overland flow was significantly impacted by both burning and time since burn with significantly less overland flow recorded for more recently burnt sites. This ties in well with our water table data since blanket peat systems are dominated by saturation processes rather than infiltration-excess overland flow. In this presentation we focus on the hydrological findings from the EMBER project but where relevant we relate these to other supporting environmental data we collected in order to interrogate process explanations for the differences we observed. For example, surface and near-surface peat temperatures were significantly more variable (both warmer and cooler depending on season and time of day) for burnt sites (and for patches burnt < 5 yrs prior to monitoring within burnt sites) but with warmer peat associated with burning overall. The results provide clear evidence that prescribed vegetation burning on blanket peat significantly impacts peatland hydrology at both the plot and stream scale and therefore raises issues for government bodies who have legal responsibility to protect many peatland landscapes, their integrity, their biogeochemical functions and the ecosystem services that peatlands provide.

The distribution and migration of sodium from a reclaimed upland to a constructed fen peatland in a post-mined oil sands landscape.

PubMed

Kessel, Eric D; Ketcheson, Scott J; Price, Jonathan S

2018-07-15

Post-mine landscape reclamation of the Athabasca Oil Sands Region requires the use of tailings sand, an abundant mine-waste material that often contains large amounts of sodium (Na + ). Due to the mobility of Na + in groundwater and its effects on vegetation, water quality is a concern when incorporating mine waste materials, especially when attempting to construct groundwater-fed peatlands. This research is the first published account of Na + redistribution in groundwater from a constructed tailings sand upland to an adjacent constructed fen peat deposit (Nikanotee Fen). A permeable petroleum coke layer underlying the fen, extending partway into the upland, was important in directing flow and Na + beneath the peat, as designed. Initially, Na + concentration was highest in the tailings sand (average of 232mgL -1 ) and lowest in fen peat (96mgL -1 ). Precipitation-driven recharge to the upland controlled the mass flux of Na from upland to fen, which ranged from 2 to 13tons Na + per year. The mass flux was highest in the driest summer, in part from dry-period flowpaths that direct groundwater with higher concentrations of Na + into the coke layer, and in part because of the high evapotranspiration loss from the fen in dry periods, which induces upward water flow. With the estimated flux rates of 336mmyr -1 , the Na + arrival time to the fen surface was estimated to be between 4 and 11years. Over the four-year study, average Na + concentrations within the fen rooting zone increased from 87 to 200mgL -1 , and in the tailings sand decreased to 196mgL -1 . The planting of more salt-tolerant vegetation in the fen is recommended, given the potential for Na + accumulation. This study shows reclamation designs can use layered flow system to control the rate, pattern, and timing of solute interactions with surface soil systems. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

A pore-size classification for peat bogs derived from unsaturated hydraulic properties

NASA Astrophysics Data System (ADS)

Weber, Tobias Karl David; Iden, Sascha Christian; Durner, Wolfgang

2017-12-01

In ombrotrophic peatlands, the moisture content of the acrotelm (vadoze zone) controls oxygen diffusion rates, redox state, and the turnover of organic matter. Thus, variably saturated flow processes determine whether peatlands act as sinks or sources of atmospheric carbon, and modelling these processes is crucial to assess effects of changed environmental conditions on the future development of these ecosystems. We show that the Richards equation can be used to accurately describe the moisture dynamics under evaporative conditions in variably saturated peat soil, encompassing the transition from the topmost living moss layer to the decomposed peat as part of the vadose zone. Soil hydraulic properties (SHP) were identified by inverse simulation of evaporation experiments on samples from the entire acrotelm. To obtain consistent descriptions of the observations, the traditional van Genuchten-Mualem model was extended to account for non-capillary water storage and flow. We found that the SHP of the uppermost moss layer reflect a pore-size distribution (PSD) that combines three distinct pore systems of the Sphagnum moss. For deeper samples, acrotelm pedogenesis changes the shape of the SHP due to the collapse of inter-plant pores and an infill with smaller particles. This leads to gradually more homogeneous and bi-modal PSDs with increasing depth, which in turn can serve as a proxy for increasing state of pedogenesis in peatlands. From this, we derive a nomenclature and size classification for the pore spaces of Sphagnum mosses and define inter-, intra-, and inner-plant pore spaces, with effective pore diameters of > 300, 300-30, and 30-10 µm, respectively.

Drained peatlands used for extraction and agriculture: biogeochemical status with special attention to greenhouse gas fluxes and rewetting

NASA Astrophysics Data System (ADS)

Sirin, Andrey; Chistotin, Maxim; Suvorov, Gennady; Glagolev, Mikhail; Kravchenko, Irina; Minaeva, Tatiana

2010-05-01

Many peatlands previously drained for peat extraction or utilized for agriculture (directly or after partial cutoff) are left abandoned during last decades in Europe, and especially in its eastern part. In the European part of Russia alone, several million hectares of peatlands have been modified for peat extraction and agriculture by direct water level draw-down and nowadays are not under use by economic reasons. This makes up one of the most serious and urgent problems of wise use and management of peatlands in these regions with serious feedback to people, environment and economy (Quick Scan of Peatlands in Central and Eastern Europe, 2009). Drainage for agriculture leads to peat oxidation resulting in substantial emissions of greenhouse gases (carbon dioxide and sometimes nitrous oxide) to the atmosphere. Together with peat fires this is the most significant negative input of peatland degradation to climate change (Assessment on Peatlands Biodiversity and Climate Change, 2008; Peatlands and Climate Change, 2008). Besides that, dehydrated peatlands often release methane. Starting from 2003, the effect of drainage and subsequent utilization of peatlands on the emissions of carbon dioxide and methane was studied in Tomsk region (West Siberia) during the summer-fall periods (Glagolev et al. 2008). The measurements were conducted by chamber method at peatlands drained for use as croplands (now partly being fallows) and peat cutting (currently abandoned or reclaimed for forest planting, haying, or pasturing), as well as at a wide range of undrained oligotrophic, mesotrophic, and eutrophic mires and burnt mire areas of different regeneration stages. The statistical analysis of data from a large number of study sites indicated a higher release of carbon dioxide from disturbed peatlands compared to undrained ones. At the same time some drained peatlands had considerable methane emission rates, additionally enhanced by the intensive efflux from the surface of drainage ditches. The findings were supported by the studies conducted from 2005 at drained peatland sites in Moscow region (European part of Russia) which are used for peat extraction or as hayfield (Chistotin et al., 2006). Unexpected transient methane fluxes were observed at the inter-ditch surfaces in two types of sites: milled peat extraction area and used as a hay field after partial peat extraction. Under warm and wet conditions methane was released even from peat stockpiles. Microbiological studies showed not lower and near to twice higher genomic diversity of methanogens in extracted sites and in a hayfield as compared to virgin mire. We suppose that well-developed plant roots at the grassland provide a source of fresh organic material used for CH4 production. To test this hypothesis, a pot experiment with mesocosms which model three succession stages (bare peat, grass sowing, and developed grassland) under permanently high or fluctuating wetness was conducted. Methane efflux from peat under developed grassland was higher as compared to the other treatments. Under permanently high water supply the methane emission was 1 to 2 orders of magnitude higher. The obtained results clearly showed that plant organic matter can be an additional source of methane after rewetting which is obviously needed for abandoned peatland sites not used for agriculture any more. To mitigate the emissions, such management options as removal of the surface peat layer before rewetting could be applied. This practice could have additional benefits achieved by bringing day surface closer to ground water table level and forming more favorable soil conditions for mire species.

Effects of a raised water table on greenhouse gas emissions and celery yield from agricultural peat under climate warming conditions

NASA Astrophysics Data System (ADS)

Matysek, Magdalena; Zona, Donatella; Leake, Jonathan; Banwart, Steven

2017-04-01

Peatlands are globally important areas for carbon preservation: covering only 3% of world's land, they store 30% of total soil carbon. At the same time, peat soils are widely utilised in agriculture: in Europe 14% of peatland area is under cultivation, 40% of UK peatlands have been drained for agricultural use and 24% of deep peat area in England is being farmed. One of the most important regions for crop production on lowland peats in the UK are the East Anglian Fenlands (the Fens): an area of drained peatlands in East England. 88% of the Fenland area is cultivated, sustaining around 4000 farms and supplying 37% of total vegetable production in England. The soils of the area are fertile (89% of agricultural land being classified as grade 1 or 2) and so crops with high nutritional demands tend to dominate. It is estimated that Fenland peats store 41 Tg of Carbon, which is lost from the ecosystem at a rate of 0.4 Tg C/yr. The Fens are at risk due to continued drainage-induced volume loss of the peat layer via shrinkage, compaction and oxidation, which are estimated to result in wastage rate of 2.1 cm/yr. Cultivation of peat soil requires drainage as most crops are intolerant of root-zone anoxia: this leads to creation of oxic conditions in which organic matter becomes vulnerable to mineralisation by aerobic microorganisms. It is, therefore, crucial to find a water table level which would minimise peat loss and at the same time allow for economically viable crop growth. Despite the importance of preservation of agricultural peats, there is a lack of studies which attempt to find water table level that strikes a balance between crop yield and greenhouse gas production. The future of the Fens is overshadowed by another uncertainty: increases in temperature brought by the climate change. It is estimated that average global temperature increase expected by the end of this century (relative to 1986-2005) would be within the range of 0.3-4.8°C, depending on the scenario. Rising temperatures should accelerate the rate of organic matter mineralisation, which will lead to higher emissions of greenhouse gases as well as enhanced plant growth due to better availability of nutrients. The effects of higher temperatures on crop growth and greenhouse gas emission have not been properly investigated in the context of agriculturally-utilised peatlands. This study was conducted on peat cores excavated from a field in the Fens and focused on the following objectives: 1. To examine effects of climate change-induced temperature rises on celery productivity and peat CO2 and CH4 emissions. 2. To find the field water table level that reduces peat emissions of CO2 and CH4 while maintaining celery productivity. The research found higher CO2 emissions from the elevated (+5°C) temperature treatment and lower CO2 emissions from the higher (-30cm) water table level, however, noted no effect on CH4 emissions of any of the treatments. The higher water table decreased aboveground celery biomass. There was no effect of increased temperature on aboveground celery yield.

Chemical properties of peat used in balneology

NASA Astrophysics Data System (ADS)

Szajdak, L.; Hładoń, T.

2009-04-01

The physiological activity of peats is observed in human peat-bath therapy and in the promotion of growth in some plants. Balneological peat as an ecologically clean and natural substance is perceived as being more 'human friendly' than synthetic compounds. Poland has a long tradition of using balneological peat for therapeutic purposes. Balneological peat reveals a physical effect by altering temperature and biochemical effects through biologically active substances. It is mainly used for the treatment of rheumatic diseases that are quite common in Poland. Peat represents natural product. Physico-chemical properties of peat in particular surface-active, sorption and ion exchanges, defining their biological function, depend mainly on the chemical composition and molecular structure of humic substances representing the major constituent of organic soil (peat). The carbon of organic matter of peats is composed of 10 to 20% carbohydrates, primarily of microbial origin; 20% nitrogen-containing constituents, such as amino acids and amino sugars; 10 to 20% aliphatic fatty acids, alkanes, etc.; with the rest of carbon being aromatic. For balneology peat should be highly decomposed (preferably H8), natural and clean. The content of humic acids should exceed 20% of dry weight, ash content will be less than 15 15% of dry weight, sulphur content less than 0.3% of dry weight and the amount of water more than 85%. It will not contain harmful bacteria and heavy metals. Humic substances (HS) of peat are known to be macromolecular polydisperse biphyllic systems including both hydrophobic domains (saturated hydrocarbon chains, aromatic structural units) and hydrophilic functional groups, i. e having amphiphilic character. Amphiphilic properties of FA are responsible for their solubility, viscosity, conformation, surfactant-like character and a variety of physicochemical properties of considerable biologically practical significance. The chemical composition of peats depends significantly on the genesis of peatlands and the depth of sampling. The chemical properties of peat fulvic acids (FA) have some genetic peculiarities due to the specific conditions of the process of humification of peat-forming plants in mires. The process of humification in mires takes place in the top-forming layer under amphibious moisture conditions. Substances of microbial origin are water-soluble and can participate in the formation of peat FA to a little extent. So a main source of structural units for the peat HA and FA is suggested to be organic constituents of peat forming plants of various botanical composition. The content of aromatic units in peat FA was shown to depend on the content of lignin in peat-forming plants and also of the aromatization of polysaccharides mainly due to the transformation of cellulose. FA characterized lower than humic acids molecular weight (1000-30,000). FA's are composed of a series of highly oxidized aromatic rings with a large number of side chains. Building blocks are benzene carboxylic acids and phenolic acids. These are held together by hydrogen bonding van der Waals' forces and ionic bonding. FA contains larger concentrations of nitrogen. This fraction also contains a great deal of polysaccharide materials, as well as low molecular fatty acids and cytoplasmic constituents of microorganisms. These compounds are linear, flexible colloids at low concentrations, and spherical colloids at high solution concentrations and low pH values. A more adequate knowledge of the chemical structure of humic materials will assist us in better understanding the physiological effects and also the function of these macromolecules on the health that these materials are know to exert. This improved knowledge provides us better information on chemical structure of humic substances from peats, which are responsible for pharmacotherapeutic, pharmacokinetic and biopharmaceutical effect. This structure of FA creates proper conditions for uptake of nutrient as well as bioavailability of biologically active substances. The solubilization in water by humic materials of organic substances which are otherwise water-insoluble is a matter of considerable interest to chemist deals with the problem of the function of organic matter. There has been considerable evidence that humic substances can "complex" with several biologically active substances and so modify their physiological activity. It has been noteworthy that FA can "fix" high-molecular weight water-insoluble organic compounds and make them water-soluble. FA may so act as a vehicle for the mobilization, transport and immobilization of such substances in physiological conditions. Analysis of HA and FA carried out by several analytical methods revealed that there were no chemical interaction among biologically active substances but that latter was firmly adsorbed, possible by hydrogen-bonding, on the FA surfaces. Amino acids account for the majority of organic N fraction in humic substances. Most of the amino acids in organic matter occur in bound form in the humino-peptides fraction. These amino acids are commonly bound to the central core of FA. These humino-peptides fraction of FA mediate in respiration and act as hydrogen acceptors, thus affecting oxidation-reaction reactions. Thus, what is needed at this time is more fundamental research in order to solve practical pharmacological, pharmacokinetic and biopharmaceutical problem of great significance for human health.

Examination of mercury and organic carbon dynamics from a constructed fen in the Athabasca oil sands region, Alberta, Canada using in situ and laboratory fluorescence measurements

NASA Astrophysics Data System (ADS)

Oswald, C.; Carey, S. K.

2013-12-01

In the Athabasca oil sands region, mined landscapes must be reclaimed to a functioning natural ecosystem as part of the mine closure process. To test wetland construction techniques on oil sands tailings, 55 ha of mined landscape on the Syncrude Canada Ltd. property is being reclaimed to a watershed containing a graminoid fen. The 18 ha constructed fen consists of an approximately 50 cm thick peat-mineral soil layer separated from underlying tailings sand by a thin layer of clay till. The water table in the fen is maintained by pumping water into the fen from a nearby lake and controlling outflow with under-drains. The objective of this study was to assess total mercury (THg) and methyl mercury (MeHg) concentration dynamics in water exported from the fen in relation to organic carbon quantity and composition. Water quality data from summer 2012 when the fen pumps were first turned on show that dissolved organic carbon (DOC) concentrations are on average twice as high in water flowing through the underlying tailings sand aquifer (median: 42.0 mg/L) compared to DOC concentrations in water flowing through the fen peat package (median: 20.3 mg/L). Given these DOC concentrations, filtered THg concentrations are very low (median values are 0.81 ng/L and 0.17 ng/L for water flowing through the fen peat and sand tailings, respectively) compared to concentrations reported for other boreal wetlands. Although a relationship was identified between filtered THg and DOC (r2=0.60), its slope (0.06 ng Hg/mg C) is an order-of-magnitude smaller than the typical range of slopes found at other wetland sites potentially suggesting a small pool of mercury in the peat and/or limited partitioning of mercury into solution. Filtered MeHg concentrations in all water samples are near the limit of detection and suggest that biogeochemical conditions conducive to methylation did not exist in the fen peat or tailings sand at the time of sampling. In addition to these baseline THg and MeHg results that will be used to assess the evolution of mercury dynamics in the fen as the hydrology and vegetation become established, we are investigating the composition of dissolved organic matter (DOM) using optical techniques in the water flowing through the fen peat and underlying tailing sand aquifer. During 2013, continuous in situ measurements of chromophoric DOM fluorescence (FDOM) were measured at the fen outlet to identify sources of C and their relative contribution to discharge waters. We compare these field measurements to laboratory measurements of FDOM on discrete water samples using a benchtop spectrofluorometer to develop relationships between FDOM, DOC and filtered THg and MeHg. The use of continuous in situ FDOM measurements as a proxy for DOC and mercury concentrations will improve our understanding of the effects of hydrologic management and natural seasonal variations in fen hydrology on DOC and Hg fluxes from different soil layers in the constructed system. Furthermore, we expect that the modeling of excitation-emission matrices using parallel factor analysis on discrete water samples will provide important information on the sources and reactivity of organic carbon being transported through different soil compartments in the fen.

PALADYN v1.0, a comprehensive land surface-vegetation-carbon cycle model of intermediate complexity

NASA Astrophysics Data System (ADS)

Willeit, Matteo; Ganopolski, Andrey

2016-10-01

PALADYN is presented; it is a new comprehensive and computationally efficient land surface-vegetation-carbon cycle model designed to be used in Earth system models of intermediate complexity for long-term simulations and paleoclimate studies. The model treats in a consistent manner the interaction between atmosphere, terrestrial vegetation and soil through the fluxes of energy, water and carbon. Energy, water and carbon are conserved. PALADYN explicitly treats permafrost, both in physical processes and as an important carbon pool. It distinguishes nine surface types: five different vegetation types, bare soil, land ice, lake and ocean shelf. Including the ocean shelf allows the treatment of continuous changes in sea level and shelf area associated with glacial cycles. Over each surface type, the model solves the surface energy balance and computes the fluxes of sensible, latent and ground heat and upward shortwave and longwave radiation. The model includes a single snow layer. Vegetation and bare soil share a single soil column. The soil is vertically discretized into five layers where prognostic equations for temperature, water and carbon are consistently solved. Phase changes of water in the soil are explicitly considered. A surface hydrology module computes precipitation interception by vegetation, surface runoff and soil infiltration. The soil water equation is based on Darcy's law. Given soil water content, the wetland fraction is computed based on a topographic index. The temperature profile is also computed in the upper part of ice sheets and in the ocean shelf soil. Photosynthesis is computed using a light use efficiency model. Carbon assimilation by vegetation is coupled to the transpiration of water through stomatal conductance. PALADYN includes a dynamic vegetation module with five plant functional types competing for the grid cell share with their respective net primary productivity. PALADYN distinguishes between mineral soil carbon, peat carbon, buried carbon and shelf carbon. Each soil carbon type has its own soil carbon pools generally represented by a litter, a fast and a slow carbon pool in each soil layer. Carbon can be redistributed between the layers by vertical diffusion and advection. For the vegetated macro surface type, decomposition is a function of soil temperature and soil moisture. Carbon in permanently frozen layers is assigned a long turnover time which effectively locks carbon in permafrost. Carbon buried below ice sheets and on flooded ocean shelves is treated differently. The model also includes a dynamic peat module. PALADYN includes carbon isotopes 13C and 14C, which are tracked through all carbon pools. Isotopic discrimination is modelled only during photosynthesis. A simple methane module is implemented to represent methane emissions from anaerobic carbon decomposition in wetlands (including peatlands) and flooded ocean shelf. The model description is accompanied by a thorough model evaluation in offline mode for the present day and the historical period.

Characterization of aquifer heterogeneity using Cyclostratigraphy and geophysical methods in the upper part of the Karstic Biscayne Aquifer, Southeastern Florida

USGS Publications Warehouse

Cunningham, Kevin J.; Carlson, Janine L.; Wingard, G. Lynn; Robinson, Edward; Wacker, Michael A.

2004-01-01

This report identifies and characterizes candidate ground-water flow zones in the upper part of the shallow, eogenetic karst limestone of the Biscayne aquifer in the Lake Belt area of north-central Miami-Dade County using cyclostratigraphy, ground-penetrating radar (GPR), borehole geophysical logs, and continuously drilled cores. About 60 miles of GPR profiles were used to calculate depths to shallow geologic contacts and hydrogeologic units, image karst features, and produce qualitative views of the porosity distribution. Descriptions of the lithology, rock fabrics, and cyclostratigraphy, and interpretation of depositional environments of 50 test coreholes were linked to the geophysical interpretations to provide an accurate hydrogeologic framework. Molluscan and benthic foraminiferal paleontologic constraints guided interpretation of depositional environments represented by rockfabric facies. Digital borehole images were used to characterize and quantify large-scale vuggy porosity. Preliminary heat-pulse flowmeter data were coupled with the digital borehole image data to identify candidate ground-water flow zones. Combined results show that the porosity and permeability of the karst limestone of the Biscayne aquifer have a highly heterogeneous and anisotropic distribution that is mostly related to secondary porosity overprinting vertical stacking of rock-fabric facies within high-frequency cycles (HFCs). This distribution of porosity produces a dual-porosity system consisting of diffuse-carbonate and conduit flow zones. The nonuniform ground-water flow in the upper part of the Biscayne aquifer is mostly localized through secondary permeability, the result of solution-enlarged carbonate grains, depositional textures, bedding planes, cracks, root molds, and paleokarst surfaces. Many of the resulting pore types are classified as touching vugs. GPR, borehole geophysical logs, and whole-core analyses show that there is an empirical relation between formation porosity, permeability, formation electrical conductivity, and GPR reflection amplitudes? as porosity and permeability increase, formation electrical conductivity increases and reflection amplitude decreases. This relation was observed throughout the entire vertical and lateral section of the upper part of the Biscayne aquifer in the study area. Further, upward-shallowing brackish- or freshwatercapped cycles of the upper part of the Fort Thompson Formation show low-amplitude reflections near their base that correspond to relatively higher porosity and permeability. This distribution is related to a systematic vertical stacking of rock-fabric facies within the cycle. Inferred flow characteristics of the porosity distribution within the upper part of the Biscayne aquifer were used to identify four ground-water flow classes, with each characterized by a discrete pore system that affects vertical and horizontal groundwater flow: (1) a low-permeability peat, muck, and marl ground-water flow class; (2) a horizontal conduit ground-water flow class; (3) a leaky, low-permeability ground-water flow class; and (4) a diffuse-carbonate ground-water flow class. At the top of the Biscayne aquifer, peat, muck, and marl can combine to form a relatively low-permeability layer of Holocene sediment that water moves through slowly. Most horizontal conduit flow is inferred to occur along touching vugs in portions of the following rock-fabric facies: (1) touchingvug pelecypod floatstone and rudstone, (2) sandy touching-vug pelecypod floatstone and rudstone, (3) vuggy wackestone and packstone, (4) laminated peloid grainstone and packstone, (5) peloid grainstone and packstone, and (6) peloid wackestone and packstone. Gastropod floatstone and rudstone, mudstone and wackestone, and pedogenic limestone rock-fabric facies are the main hosts for leaky, low-permeability units. This study provides evidence that the limestone that spans the base of the Miami Limestone and top of the Fort Thompson

A cost-efficient method to assess carbon stocks in tropical peat soil

NASA Astrophysics Data System (ADS)

Warren, M. W.; Kauffman, J. B.; Murdiyarso, D.; Anshari, G.; Hergoualc'h, K.; Kurnianto, S.; Purbopuspito, J.; Gusmayanti, E.; Afifudin, M.; Rahajoe, J.; Alhamd, L.; Limin, S.; Iswandi, A.

2012-11-01

Estimation of belowground carbon stocks in tropical wetland forests requires funding for laboratory analyses and suitable facilities, which are often lacking in developing nations where most tropical wetlands are found. It is therefore beneficial to develop simple analytical tools to assist belowground carbon estimation where financial and technical limitations are common. Here we use published and original data to describe soil carbon density (kgC m-3; Cd) as a function of bulk density (gC cm-3; Bd), which can be used to rapidly estimate belowground carbon storage using Bd measurements only. Predicted carbon densities and stocks are compared with those obtained from direct carbon analysis for ten peat swamp forest stands in three national parks of Indonesia. Analysis of soil carbon density and bulk density from the literature indicated a strong linear relationship (Cd = Bd × 495.14 + 5.41, R2 = 0.93, n = 151) for soils with organic C content > 40%. As organic C content decreases, the relationship between Cd and Bd becomes less predictable as soil texture becomes an important determinant of Cd. The equation predicted belowground C stocks to within 0.92% to 9.57% of observed values. Average bulk density of collected peat samples was 0.127 g cm-3, which is in the upper range of previous reports for Southeast Asian peatlands. When original data were included, the revised equation Cd = Bd × 468.76 + 5.82, with R2 = 0.95 and n = 712, was slightly below the lower 95% confidence interval of the original equation, and tended to decrease Cd estimates. We recommend this last equation for a rapid estimation of soil C stocks for well-developed peat soils where C content > 40%.

Storage dynamics in hydropedological units control hillslope connectivity, runoff generation, and the evolution of catchment transit time distributions

PubMed Central

Tetzlaff, D; Birkel, C; Dick, J; Geris, J; Soulsby, C

2014-01-01

We examined the storage dynamics and isotopic composition of soil water over 12 months in three hydropedological units in order to understand runoff generation in a montane catchment. The units form classic catena sequences from freely draining podzols on steep upper hillslopes through peaty gleys in shallower lower slopes to deeper peats in the riparian zone. The peaty gleys and peats remained saturated throughout the year, while the podzols showed distinct wetting and drying cycles. In this region, most precipitation events are <10 mm in magnitude, and storm runoff is mainly generated from the peats and peaty gleys, with runoff coefficients (RCs) typically <10%. In larger events the podzolic soils become strongly connected to the saturated areas, and RCs can exceed 40%. Isotopic variations in precipitation are significantly damped in the organic-rich soil surface horizons due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the dynamics strongly reflect those of the near-surface waters in the riparian peats. “pre-event” water typically accounts for >80% of flow, even in large events, reflecting the displacement of water from the riparian soils that has been stored in the catchment for >2 years. These riparian areas are the key zone where different source waters mix. Our study is novel in showing that they act as “isostats,” not only regulating the isotopic composition of stream water, but also integrating the transit time distribution for the catchment. Key Points Hillslope connectivity is controlled by small storage changes in soil units Different catchment source waters mix in large riparian wetland storage Isotopes show riparian wetlands set the catchment transit time distribution PMID:25506098

Sequence stratigraphic distribution of coaly rocks: Fundamental controls and paralic examples

USGS Publications Warehouse

Bohacs, K.; Suter, J.

1997-01-01

Significant volumes of terrigenous organic matter can be preserved to form coals only when and where the overall increase in accommodation approximately equals the production rate of peat. Accommodation is a function of subsidence and base level. For mires, base level is very specifically the groundwater table. In paralic settings, the groundwater table is strongly controlled by sea level and the precipitation/evaporation ratio. Peat accumulates over a range of rates, but always with a definite maximum rate set by original organic productivity and space available below depositional base level (groundwater table). Below a threshold accommodation rate (nonzero), no continuous peats accumulate, due to falling or low groundwater table, sedimentary bypass, and extensive erosion by fluvial channels. This is typical of upper highstand, lowstand fan, and basal lowstand-wedge systems tracts. Higher accommodation rates provide relatively stable conditions with rising groundwater tables. Mires initiate and thrive, quickly filling local accommodation vertically and expanding laterally, favoring accumulation of laterally continuous coals in paralic zones within both middle lowstand and middle highstand systems tracts. If the accommodation increase balances or slightly exceeds organic productivity, mires accumulate peat vertically, yielding thicker, more isolated coals most likely during of late lowstand-early transgressive and late transgressive-early highstand periods. At very large accommodation increases, mires are stressed and eventually inundated by clastics or standing water (as in middle transgressive systems tracts). These relations should be valid for mires in all settings, including alluvial, lake plain, and paralic. The tie to sea level in paralic zones depends on local subsidence, sediment supply, and groundwater regimes. These concepts are also useful for investigating the distribution of seal and reservoir facies in nonmarine settings.

Storage dynamics in hydropedological units control hillslope connectivity, runoff generation, and the evolution of catchment transit time distributions.

PubMed

Tetzlaff, D; Birkel, C; Dick, J; Geris, J; Soulsby, C

2014-02-01

We examined the storage dynamics and isotopic composition of soil water over 12 months in three hydropedological units in order to understand runoff generation in a montane catchment. The units form classic catena sequences from freely draining podzols on steep upper hillslopes through peaty gleys in shallower lower slopes to deeper peats in the riparian zone. The peaty gleys and peats remained saturated throughout the year, while the podzols showed distinct wetting and drying cycles. In this region, most precipitation events are <10 mm in magnitude, and storm runoff is mainly generated from the peats and peaty gleys, with runoff coefficients (RCs) typically <10%. In larger events the podzolic soils become strongly connected to the saturated areas, and RCs can exceed 40%. Isotopic variations in precipitation are significantly damped in the organic-rich soil surface horizons due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the dynamics strongly reflect those of the near-surface waters in the riparian peats. "pre-event" water typically accounts for >80% of flow, even in large events, reflecting the displacement of water from the riparian soils that has been stored in the catchment for >2 years. These riparian areas are the key zone where different source waters mix. Our study is novel in showing that they act as "isostats," not only regulating the isotopic composition of stream water, but also integrating the transit time distribution for the catchment. Hillslope connectivity is controlled by small storage changes in soil unitsDifferent catchment source waters mix in large riparian wetland storageIsotopes show riparian wetlands set the catchment transit time distribution.

The transport dynamics of chloride and sodium in a ladder fen during a continuous wastewater polishing experiment

NASA Astrophysics Data System (ADS)

McCarter, Colin P. R.; Price, Jonathan S.

2017-06-01

Ladder fen peatlands have excellent potential for wastewater polishing as they naturally contain both open water (pools) and subsurface (peat) treatment landforms; however, there is a poor understanding of solute transport in ladder fens with and without the increased hydrological load imposed by wastewater discharge. To better understand solute transport in ladder fens under wastewater polishing conditions a continuous solute (NaCl) tracer experiment (38 m3 day-1 of water, chloride - 47.2 mg L-1, and sodium - 25.3 mg L-1) was conducted during the summer of 2014 (day of year 192-243) in a small ladder fen in the James Bay Lowland. The transmissivity distribution and effective porosity (average 0.5) of the peat ribs were determined through repeated bail tests and the drainable porosity of 18 peat cores at -100 mb, respectively. Water samples were taken at least every 7 days to capture the solute (sodium and chloride) plumes. Both solute plumes never reached the site outflow (∼250 m downgradient) and displayed complex plume morphology, typically following the patterns of higher hydraulic conductivity within the upper 0.1 m of the saturated peat, rather than the microtopography. Based on the 50% breakthrough isotherms, sodium and chloride were transported at an average solute velocity of 1.9 and 1.1 m day-1, respectively (average linear groundwater velocity = 2.1 m day-1); thus, the solutes were retarded by a factor of 2.1 and 1.2 for sodium and chloride, respectively. Due to the inherent retardation of solutes into inactive pores and relatively high solute residence times, this study demonstrates the potential for wastewater polishing in ladder fens.

Peat soil properties and erodibility: what factors affect erosion and suspended sediment yields in peat extraction areas?

NASA Astrophysics Data System (ADS)

Tuukkanen, Tapio; Marttila, Hannu; Kløve, Bjørn

2014-05-01

Peatland drainage and peat extraction operations change soil properties and expose bare peat to erosion forces, resulting in increased suspended sediment (SS) loads to downstream water bodies. SS yields from peat extraction areas are known to vary significantly between sites, but the contribution of peat properties and catchment characteristics to this variation is not well understood. In this study, we investigated peat erosion at 20 Finnish peat extraction sites by conducting in situ and laboratory measurements on peat erodibility and associated peat properties (degree of humification, peat type, bulk density, loss on ignition, porosity, moisture content, and shear strength), and by comparing the results with monitored long-term SS concentrations and loads at each catchment outlet. Here, we used a cohesive strength meter (CSM) to measure direct erosion thresholds for undisturbed soil cores collected from each study site. The results suggested that the degree of peat decomposition clearly affects peat erodibility and explains much of the variation in SS concentration between the study sites. According to CSM tests, critical shear stresses for particle entrainment were lowest (on average) in well-decomposed peat samples, while undecomposed, dry and fiber rich peat generally resisted erosion very well. Furthermore, the results indicated that two separate critical shear stresses often exist in moderately decomposed peat. In these cases, the well-decomposed parts of peat samples eroded first at relatively low shear stresses and remaining peat fibers prevented further erosion until a much higher shear stress was reached. In addition to peat soil properties, the study showed that the erosion of mineral subsoil may play a key role in runoff water SS concentration at peat extraction areas with drainage ditches extending into the mineral soil. The interactions between peat properties and peat erodibility found in this study as well as critical shear stress values obtained can be used for several purposes in e.g. water conservation and sediment management planning for peat extraction areas and other bare peat-covered catchments.

Long-Life Self-Renewing Solar Reflector Stack

DOEpatents

Butler, Barry Lynn

1997-07-08

A long-life solar reflector includes a solar collector substrate and a base layer bonded to a solar collector substrate. The first layer includes a first reflective layer and a first acrylic or transparent polymer layer covering the first reflective layer to prevent exposure of the first reflective layer. The reflector also includes at least one upper layer removably bonded to the first acrylic or transparent polymer layer of the base layer. The upper layer includes a second reflective layer and a second acrylic or transparent polymer layer covering the second reflective layer to prevent exposure of the second reflective layer. The upper layer may be removed from the base reflective layer to expose the base layer, thereby lengthening the useful life of the solar reflector. A method of manufacturing a solar reflector includes the steps of bonding a base layer to a solar collector substrate, wherein the base reflective layer includes a first reflective layer and a first transparent polymer or acrylic layer covering the first reflective layer; and removably bonding a first upper layer to the first transparent polymer or acrylic layer of the base layer. The first upper layer includes a second reflective layer and a second transparent polymer or acrylic layer covering the second reflective layer to prevent exposure of the second reflective layer.

A Millennial-Scale Record of Mercury and Lead Contamination in Peatlands of the Sacramento-San Joaquin Delta of California

NASA Astrophysics Data System (ADS)

Drexler, J. Z.; Alpers, C. N.; Neymark, L. A.; Paces, J. B.; Fuller, C.

2015-12-01

Peat cores from two micro-tidal marshes in the Sacramento-San Joaquin Delta of California (the landward end of the San Francisco Estuary) were used to track the onset of anthropogenic pollution on the west coast of the United States. Cores were sectioned into 2-cm depth intervals and analyzed for lead (Pb), mercury (Hg), and titanium (Ti) concentrations and Pb isotope compositions. Peat profiles were dated using radiocarbon, 210Pb, and 137Cs. Pre-anthropogenic concentrations of Pb and Hg in peat ranged from 0.60 to 13.0 μg g-1and from 6.9 to 71 ng g-1, respectively. For much of the past 6,000+ years, the Delta was free from anthropogenic pollution; however, beginning in ~1425 CE, Hg and Pb concentrations, Pb/Ti ratios, Pb enrichment factors (EFs), and HgEFs all increased. Pb isotope compositions of the peat suggest that this uptick was likely caused by mining and smelting activities originating in Asia. The next increases in Pb and Hg contamination occurred during the California Gold Rush (beginning ~1850 CE), when concentrations reached their highest levels (74 μg g-1 Pb, 990 ng g-1 Hg; PbEF = 12 and HgEF = 28). Pb concentrations increased again beginning in the ~1920s with the incorporation of Pb additives in gasoline. The phase-out of lead additives in the late 1980s was reflected in Pb isotope ratios and reductions in Pb concentrations in the surface layers of the peat. The rise and fall of Hg contamination was also tracked by the peat archive, with the highest Hg concentrations occurring just before 1963 CE and then decreasing during the post-1963 period. Overall the results show that the Delta was a pristine region for most of its ~6,700-year existence; however, since ~1425 CE, it has received Pb and Hg contamination from both global and regional sources. This study demonstrates that micro-tidal peatlands can be a highly useful archive for establishing the onset of anthropogenic contamination and chronicling the transition from a pristine to a polluted landscape.

Transport and thermodynamics constrain belowground carbon turnover in a northern peatland

NASA Astrophysics Data System (ADS)

Beer, Julia; Blodau, Christian

2007-06-01

Rates of anaerobic respiration are of central importance for the long-term burial of carbon (C) in peatlands, which are a relevant sink in the global C cycle. To identify constraints on anaerobic peat decomposition, we determined detailed concentration depth profiles of decomposition end-products, i.e. methane (CH 4) and dissolved inorganic carbon (DIC), along with concentrations of relevant decomposition intermediates at an ombrotrophic Canadian peat bog. The magnitude of in situ net production rates of DIC and CH 4 was estimated by inverse pore-water modeling. Vertical transport in the peat was slow and dominated by diffusion leading to the buildup of DIC and CH 4 with depth (5500 μmol L -1 DIC, 500 μmol L -1 CH 4). Highest DIC and CH 4 production rates occurred close to the water table (decomposition constant kd ˜ 10 -3-10 -4 a -1) or in some distinct zones at depth ( kd ˜ 10 -4 a -1). Deeper into the peat, decomposition proceeded very slowly at about kd = 10 -7 a -1. This pattern could be related to thermodynamic and transport constraints. The accumulation of metabolic end-products diminished in situ energy yields of acetoclastic methanogenesis to the threshold for microbially mediated processes (-20 to -25 kJ mol -1 CH 4). The methanogenic precursor acetate also accumulated (150 μmol L -1). In line with these findings, CH 4 was formed by hydrogenotrophic methanogenesis at Gibbs free energies of -35 to -40 kJ mol -1 CH 4. This was indicated by an isotopic fractionation α-CH of 1.069-1.079. Fermentative degradation of acetate, propionate and butyrate attained Gibbs free energies close to 0 kJ mol -1 substrate. Although methanogenesis was apparently limited by some other factor in some peat layers, transport and thermodynamic constraints likely impeded respiratory processes in the deeper peat. Constraints on the removal of DIC and CH 4 may thus slow decomposition and contribute to the sustained burial of C in northern peatlands.

Fourth technical contractors' conference on peat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-01-01

This conference reported the status of the US Department of Energy Peat Program. The papers presented dealt with peat dewatering, international peat programs, environmental and socio-economic factors, peat gasification, peat harvesting, and the state peat surveys for 14 states. Separate abstracts were prepared for the individual papers. (CKK)

Soil microbial respiration from various microhabitats in Arctic landscape: impact of soil type, environmental conditions and soil age

NASA Astrophysics Data System (ADS)

Biasi, Christina; Jokinen, Simo; Marushchak, Maija; Trubnikova, Tatiana; Hämäläinen, Kai; Oinonen, Markku; Martikainen, Pertti

2014-05-01

Soil respiration is the second largest C flux between atmosphere and terrestrial ecosystems after gross primary production. Carbon dioxide released from soils is thus a major contributor to the atmospheric CO2 concentration. Despite the global importance, soil respiration and its components (heterotrophic and autotrophic respiration) remain poorly understood and not well constrained fluxes of the terrestrial C cycle. This is particularly true for the Arctic, where huge amounts of the Earth's soil carbon is stored. Here, we report on heterotrophic soil respiration rates from various Arctic tundra microhabitats measured in situ. The study site was Seida (67°07'N, 62°57'E, 100 m a.s.l.) which is characterized by typical sub-arctic permafrost landscape which comprises raised, vegetated permafrost peat plateaus, interspersed with spots of bare peat surfaces (peat circles), and upland mineral soils. We used isotope partitioning approach based on differences in natural abundance of 14C between soil and plants to separate sources of soil-respired CO2. In addition, the tradition trenching approach was employed. Complementary laboratory incubations with homogenized soil were conducted to assess primary decomposability of the soils and to identify age of the CO2 released and thus get more information on the nature of the sources of respiration. The major aim was to link SMR rates with of soil type, land cover class, soil physic-chemical properties (e.g. water content), soil C stocks and age of soil. Results show that, despite profound differences in soil characteristics and primary decomposability of organic matter, surface CO2 fluxes derived from soil microbial respiration rates were rather similar between microhabitats. The only factor which influenced, at least to some extent, the respiration rates was total soil C (and N) stocks in surface soils. There was some evidence for reduced soil-related CO2 emissions from peatlands, though results were not consistent between the methods applied. It seems that the lower decomposability of peat is largely outweighed by higher C stocks at field conditions. Surprisingly, the bare surfaces (peat circles) with 3500 years old C at the surface exhibited about the largest soil microbial respiration rates among all sites as shown by both methods. This is likely due to the immature status of the peat which was during the bulk of its developmental time protected by permafrost, together with high C-densities. The observation is particularly relevant for decomposition of deeper peat at the permafrost-active layer interface in the large vegetated peat plateaus, where soil material similar to the bare surfaces can be found. The results suggest that the chemical nature and high age of the soil SOC in deep peat does not solely guarantee for resistance to decay. Thus, the study highlights risks for potential re-mobilization of C in deep peat soils following thawing. Soil microbial respiration rates need to be better known when predicting the overall carbon sink/source character of tundra ecosystems in a warming climate. Biasi C., Jokinen S., Marushchak M., Hämäläinen K., Trubnikova T., Oinonen M., Martikainen P. (2013). Microbial respiration in Arctic upland and peat soils as source of CO2. Ecosystems. DOI: 10.1007/s10021-013-9710-z.

Summary of Paleotsunami Investigations in Aliomanu, Anahola, Kauai

NASA Astrophysics Data System (ADS)

Griswold, F. R.; La Selle, S.; Richmond, B. M.; Jaffe, B. E.; Gelfenbaum, G. R.; Chague-Goff, C.; LeVeque, R. J.; Bellanova, P.; Sugawara, D.; Nelson, A. R.

2016-12-01

The Hawaiian Islands are susceptible to tsunami hazards from both local and distant sources. Damaging historical tsunamis, such as the 1946 and 1957 Aleutian, and 1960 Chile tsunamis, have been observed in the Hawaiian Islands, but little is known about prehistoric tsunami events. We conducted a field survey in a freshwater marsh in Anahola Valley, on the northeast shore of Kauai, looking for prehistoric tsunami deposits. Cores were collected at 142 sites, spanning to 700 meters inland, using a vibracore, gouge augers, and Russian D-corer. The coring reveals the presence of at least three marine sand layers, which all exhibit a sharp basal contact with underlying marsh peats and muds. The two uppermost sand layers were dated by measuring 137Cs activity in the upper 50 cm of several cores. These sands were likely deposited by the 1946 and 1957 Aleutian tsunamis, both of which were observed by residents in Anahola Valley, with recorded run-ups of 5.2 m and 4.9 m, respectively. The deepest sand layer was deposited approximately 700 cal yr B.P. and may correspond to recently discovered tsunami deposits on Sedanka Island in the Aleutian Islands. In order to characterize the structure and composition of the deeper sand unit, as well as its possible origin, grain size, CT scan, and X-Ray fluorescence data were collected from the cores. We are modeling tsunami propagation and inundation in Anahola Valley to test whether the observed deposits are consistent with an Aleutian subduction zone earthquake source. Additional field investigations and analyses of candidate tsunami deposits are required in order to map the extent of this deposit throughout the Hawaiian Islands and to determine a probable source of this event.

Origin of VC-only plumes from naturally enhanced dechlorination in a peat-rich hydrogeologic setting

NASA Astrophysics Data System (ADS)

Filippini, Maria; Amorosi, Alessandro; Campo, Bruno; Herrero-Martìn, Sara; Nijenhuis, Ivonne; Parker, Beth L.; Gargini, Alessandro

2016-09-01

The occurrence of vinyl chloride (VC) is often a main concern at sites contaminated with chlorinated solvents due to its high degree of toxicity and carcinogenicity. VC occurrence in aquifers is most often related to the degradation of higher chlorinated ethenes or ethanes and it is generally detected in plumes along with parent contaminants. However, specific combination of stratigraphic, hydrogeologic and geochemical conditions can enhance the degradation of parents and lead to the formation of plumes almost entirely composed of VC (i.e. VC-only plumes). This paper investigates the causes of VC-only plumes in the aquifers below the city of Ferrara (northern Italy) by combining multiple lines of evidence. The City of Ferrara is located on an alluvial lowland, built by the River Po, and is made up of alternating unconsolidated sandy aquifer and silt-clay aquitard deposits of fluvial origin. This region has been strongly impacted by prior industrial activities, with the occurrence of chlorinated compounds at several sites. VC-only plumes with uncertain source location were found at two contaminated sites. The source zone of a third plume composed of chloroethenes from PCE to VC was investigated for high resolution depositional facies architecture and contaminant distribution (contaminant concentration and Compound Specific Isotope Analysis - CSIA). The investigation suggested that degradation of PCE and TCE takes place during contaminant migration through peat-rich (swamp) layers related to the Holocene transgression, which locally act as a ;reactor; for stimulating degradation with the accumulation of VC in the strongly reducing environment of the peat. Regional-scale stratigraphic architecture showed the ubiquitous occurrence of swamp layers at distinct stratigraphic levels in the investigated system and their apparent linkage to the in situ creation of the VC-only plumes.

Use of oil shale ash in road construction: results of follow-up environmental monitoring.

PubMed

Reinik, Janek; Irha, Natalya; Koroljova, Arina; Meriste, Tõnis

2018-01-05

Oil shale ash (OSA) was used for road construction in a pristine swamp area in East-Estonia during 2013-2014. OSA was used as a binder both in mass stabilization of soft peat soil and in the upper layer. Use of OSA in civil engineering always raises questions about the environmental safety of such activities. Post-construction environmental monitoring of the pilot section was carried out in 2014 and 2015. The monitoring program involved surface water and soil sampling campaigns. Samples were analyzed for selected constituents and parameters of environmental concern. The paper gives data for assessing the environmental impact and evaluation of potential risks associated with construction of roads using OSA. Leaching of hazardous compounds from the pilot section to surrounding aqueous environment was not observed during the monitoring program. Still, the road construction affected the concentration of sulfates in surrounding surface water. Also, the water-soluble content of barium in surface water correlated significantly with the concentrations of chloride and sulfate ion and electric conductivity of the surface water. Therefore, it is recommended to monitor the electric conductivity, concentrations of sulfates, chlorides, and barium in nearby surface water when OSA is used in road construction.

Anthropogenic contributions to atmospheric Hg, Pb and As accumulation recorded by peat cores from southern Greenland and Denmark dated using the 14C "bomb pulse curve"

NASA Astrophysics Data System (ADS)

Shotyk, W.; Goodsite, M. E.; Roos-Barraclough, F.; Frei, R.; Heinemeier, J.; Asmund, G.; Lohse, C.; Hansen, T. S.

2003-11-01

Mercury concentrations are clearly elevated in the surface and sub-surface layers of peat cores collected from a minerotrophic ("groundwater-fed") fen in southern Greenland (GL) and an ombrotrophic ("rainwater-fed") bog in Denmark (DK). Using 14C to precisely date samples since ca. AD 1950 using the "atmospheric bomb pulse," the chronology of Hg accumulation in GL is remarkably similar to the bog in DK where Hg was supplied only by atmospheric deposition: this suggests not only that Hg has been supplied to the surface layers of the minerotrophic core (GL) primarily by atmospheric inputs, but also that the peat cores have preserved a consistent record of the changing rates of atmospheric Hg accumulation. The lowest Hg fluxes in the GL core (0.3 to 0.5 μg/m 2/yr) were found in peats dating from AD 550 to AD 975, compared to the maximum of 164 μg/m 2/yr in AD 1953. Atmospheric Hg accumulation rates have since declined, with the value for 1995 (14 μg/m 2/yr) comparable to the value for 1995 obtained by published studies of atmospheric transport modelling (12 μg/m 2/yr). The greatest rates of atmospheric Hg accumulation in the DK core are also found in the sample dating from AD 1953 and are comparable in magnitude (184 μg/m 2/yr) to the GL core; again, the fluxes have since gone into strong decline. The accumulation rates recorded by the peat core for AD 1994 (14 μg/m 2/yr) are also comparable to the value for 1995 obtained by atmospheric transport modelling (18 μg/m 2/yr). Comparing the Pb/Ti and As/Ti ratios of the DK samples with the corresponding crustal ratios (or "natural background values" for preanthropogenic peat) shows that the samples dating from 1953 also contain the maximum concentration of "excess" Pb and As. The synchroneity of the enrichments of all three elements (Hg, Pb, and As) suggests a common source, with coal-burning the most likely candidate. Independent support for this interpretation was obtained from the Pb isotope data ( 206Pb/ 207Pb = 1.1481 ± 0.0002 in the leached fraction and 1.1505 ± 0.0002 in the residual fraction) which is too radiogenic to be explained in terms of gasoline lead alone, but compares well with values for U.K. coals. In contrast, the lowest values for 206Pb/ 207Pb in the DK profile (1.1370 ± 0.0003 in the leached fraction and 1.1408 ± 0.0003 in the residual fraction) are found in the sample dating from AD 1979: this shows that the maximum contribution of leaded gasoline occurred approximately 25 yr after the zenith in total anthropogenic Pb deposition.

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

NASA Astrophysics Data System (ADS)

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

2014-04-01

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

Buried Organic Layer Affects the Growth of Slash Pine in the Florida Sandhills

Treesearch

Edwin A. Hebb

1980-01-01

A technique for deep placement of organic matter within the soil, called sublayering, was tested as a means of improving Florida sandhill sites for slash pine (Pinuselliottii var. clliortii Engelm.). Single-tree plots were installed in four treatments: sublayering with peat moss, clearing, clearing plus sublayering, and no treatment.Survival was poor only on the...

Long-term effects of peatland cultivation on soil physical and hydraulic properties: Case study in Canada

Treesearch

Dennis W. Hallema; Jonathan A. Lafond; Yann Périard; Silvio J. Gumiere; Ge Sun; Jean Caron

2015-01-01

Organic soils are an excellent substrate for commercial lettuce (Lactuca sativa L.) farming; however, drainage accelerates oxidation of the surface layer and reduces the water holding capacity, which is often lethal for crops that are sensitive to water stress. In this case study, we analyzed 942 peat samples from a large cultivated peatland complex...

[Adaptability of Brazilian strains of Agaricus subrufescens Peck to fruiting on various casing materials in commercial crops].

PubMed

Pardo-Giménez, Arturo; Pardo González, José Emilio; de Figueirêdo, Vinícius Reis; Zied, Diego Cunha

2014-01-01

Agaricus subrufescens Peck is a mushroom whose cultivation has aroused great interest worldwide in recent years, and is becoming increasingly popular. A rapid expansion of culture throughout the world is foreseen because of its medicinal and culinary properties. This work assesses the effect of 5 different casing layers on the production of 3 strains of Agaricus subrufescens. A growth cycle of Agaricus subrufescens under controlled conditions has been carried out. The main production parameters were evaluated. The best results were provided by the ABL 99/30 strain. Peat-based casings have a better yield than those based on mineral soil. The highest yield (6.75kg/m(2), biological efficiency 27.57kg/dt) was provided by the combination ABL 99/30-Euroveen. Our results suggest that the combination of the strain ABL 99/30 using a peat-based casing layer (Euroveen) offers a high potential for use on a commercial scale by the edible mushroom production sector. The availability of alternatives to the usually cultivated species can make better use of resources, and increase the profitability of this activity. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Permafrost Thaw increases Emissions of Nitrous Oxide from Subarctic Peatlands

NASA Astrophysics Data System (ADS)

Voigt, C.; Marushchak, M. E.; Lamprecht, R. E.; Jackowicz-Korczynski, M.; Lindgren, A.; Mastepanov, M.; Christensen, T. R.; Granlund, L.; Tahvanainen, T.; Martikainen, P. J.; Biasi, C.

2017-12-01

Permafrost soils in the Arctic are thawing, exposing not only carbon but also large nitrogen stocks. The decomposition of this vast pool of long-term immobile C and N stocks results in the release of greenhouse gases to the atmosphere. Among these, carbon dioxide (CO2) and methane (CH4) are being studied extensively, and gaseous C release from thawing permafrost is known to be substantial. Most recent studies, however, show that Arctic soils may further be a relevant source of the strong greenhouse gas nitrous oxide (N2O). As N2O is almost 300 times more powerful in warming the climate than CO2 based on a 100-yr time horizon, the release of N2O from thawing permafrost could create a significant non-carbon permafrost-climate feedback. To study the effect of permafrost thaw on N2O fluxes, we collected peat mesocosms from a Subarctic permafrost peatland, and subjected these intact soil-plant systems to sequential thawing from the top of the active layer down to the upper permafrost layer. Measurements of N2O fluxes were coupled with detailed soil analyses and process studies. Since N2O fluxes are highly dependent on moisture conditions and vegetation cover, we applied two distinct moisture treatments (dry vs. wet) and simulated permafrost thaw in vegetated as well as in naturally bare mesocosms. Under dry conditions, permafrost thaw clearly increased N2O emissions. We observed the largest post-thaw emissions from bare peat surfaces, a typical landform in subarctic peatlands previously identified as hot spots for Arctic N2O emissions. There, permafrost thaw caused a five-fold increase in emissions (0.56 vs. 2.81 mg N2O m-2 d-1). While water-logged conditions suppressed N2O emissions, the presence of vegetation lowered, but did not prevent post-thaw N2O release. Based on these findings, we show that one fourth of the Arctic land area could be vulnerable for N2O emissions when permafrost thaws. Our results demonstrate that Arctic N2O emissions may be larger than previously thought, and that the source strength will be crucially governed by moisture conditions at times of thaw, as well as on future changes in vegetation coverage.

Recent changes in vegetation, hydrotopography and peat accumulation in detailed case studies of northern aapa mires

NASA Astrophysics Data System (ADS)

Tahvanainen, Teemu; Kumpula, Timo; Tolonen, Kimmo

2016-04-01

Aapa mires are northern mire complexes with typical patterned central fen areas and relatively thin peat layers. In principle, aapa mires could develop into raised bogs either 1) through autogenic succession, given enough time for peat accumulation or 2) through allogenic mechanism triggered by hydrological change. Climate change models predict that the climatic envelop of aapa mires will move north and, indeed, that hydrology may change sufficiently to cause allogenic change pressure. Potential resilience or pace of ecosystem-scale responses are poorly understood, however, in the case of aapa mires. We studied recent (ca. 60 years) changes in vegetation, hydrotopography and peat accumulation of two aapa mires at their southern limit of distribution in eastern Finland. We used repeated sampling after 60 years combined with peat stratigraphy and time-series of aerial images in a multi-proxy approach. The study site at the Valkeasuo mire was affected by extensive drainage activities in its catchment, while the aapa mire area itself was not drained. This resulted in the loss of minerotrophic hydrology that lead to rapid changes over the whole patterned fen area. Wet minerotrophic sedge fen vegetation was almost totally covered by ombrotrophic Sphagnum mosses within few decades. Even up to 50 cm high hummocks emerged on the patterned fen strings in an abrupt response that could be precisely dated by simultaneous encroachment of pine seedlings and from the aerial images. The recent apparent rate of carbon accumulation of the new Sphagnum peat was ca. 100 g m-2 -a. The other study site in the Ilajansuo aapa mire persists in a more pristine setting without significant disturbance in its catchment area. Here the mineral-water limit was studied across a transition between a bog zone and an aapa mire zone of the mire complex. We were able to exactly locate a 100 x 300-m special study area and repeat e.g. mapping of all trees, of all topographic patterns (hummocks, hollows, pools), 155 peat depth measurements and 38 vegetation plots. Despite the pristine wilderness character of the site, we found increased tree encroachment, significant increase of height of Sphagnum hummocks, lateral expansion of ombrotrophic bog zone over fen vegetation and increase of dwarf-shrubs typical to raised bog vegetation. Peat thickness in the bog zone had increased by 2.2 mm per year, greatly exceeding the long-term average of bogs in the region. Our case studies demonstrate a remarkable potential of ecosystem-scale responses in northern aapa mires, ecotone mire type between temperate-south boreal bogs and subarctic palsa mires. Hydrological disturbances can rapidly trigger an allogenic mechanism of fen to bog transition. Traces of ongoing changes in aapa mires can be apparent also in seemingly pristine sites when accurate repeated measurements are performed. Although the observed changes may threaten aapa mire habitat types and biota, they are progressive in terms of peat growth and carbon dioxide sequestration.

A Study of the Physical Processes of an Advection Fog BoundaryLayer

NASA Astrophysics Data System (ADS)

Liu, D.; Yan, W.; Kang, Z.; Dai, Z.; Liu, D.; Liu, M.; Cao, L.; Chen, H.

2016-12-01

Using the fog boundary layer observation collected by a moored balloon between December 1 and 2, 2009, the processes of advection fog formation and dissipation under cold and warm double-advection conditions was studied. the conclusions are as follows: 1. The advection fog process was generated by the interaction between the near-surface northeast cold advection and the upper layer's southeast warm, humid advection. The ground fog formed in an advection cooling process, and the thick fog disappeared in two hours when the wind shifted from the northeast to the northwest. The top of the fog layer remained over 600 m for most of the time. 2. This advection fog featured a double-inversion structure. The interaction between the southeast warm, humid advection of the upper layer and the descending current generated the upper inversion layer. The northeast cold advection near the ground and the warm, humid advection in the high-altitude layer formed the lower layer clouds and lower inversion layer. The upper inversion layer was composed of southeast warm, humid advection and a descending current with increasing temperature. The double inversion provided good thermal conditions for maintaining the thick fog layer. 3. The southeast wind of the upper layer not only created the upper inversion layer but also brought vapour-rich air to the fog region. The steady southeast vapour transportation by the southeast wind was the main condition that maintained the fog thickness, homogeneous density, and long duration. The low-altitude low-level jet beneath the lower inversion layer helped maintain the thickness and uniform density of the fog layer by enhancing the exchange of heat, momentum and vapour within the lower inversion layer. 4. There were three transportation mechanisms associated with this advection fog: 1) The surface layer vapour was delivered to the lower fog layer. 2) The low-altitude southeast low-level jet transported the vapour to the upper layer. 3) The vapour was exchanged between the upper and lower layers via the turbulent exchange and vertical air motion, which mixed the fog density and maintained the thickness of the fog. These mechanisms explain why the fog top was higher than the lower inversion layer and reached the upper inversion layer, as well as why this advection fog was so thick.

Identification of runoff formation with two dyes in a mid-latitude mountain headwater

NASA Astrophysics Data System (ADS)

Vlcek, Lukas; Schneider, Philipp; Falatkova, Kristyna

2017-04-01

There have been numerous studies on subsurface flow in peat bog areas, as both water scarcity and floods have led to increased attention to this specific environment and its role within the hydrological cycle. In contrast, this experimental study identifies runoff formation at two opposite hillslopes in a peaty mountain headwater; a slope with organic soils (Peat / Histosol) and shallow groundwater ( 0.5 m below surface) complemented by a slope with mineral soils (Podzol) and no detectable groundwater within 2 m below surface. Differences in infiltration, percolation, and preferential flowpaths between both hillslopes could be identified by sprinkling experiments with two dyes - Brilliant Blue FCF and Fluorescein. By excavating dye-stained soil profiles parallel ("lateral") and perpendicular ("frontal") to the slopes' gradients - both within and downstream of the sprinkling plots - dye stained flow patterns in the soil could be clearly identified. The results show that biomat flow occurred at both hillslopes. The dye solutions infiltrated into the soil and continued either as lateral subsurface pipeflow (SSF), in the case of the Peat Bog, or percolated vertically towards the bedrock in the case of the Podzol. The study provides evidence that biomat flow (BMF) - shallow, lateral preferential flowpaths along decomposed tree roots or logs - is a major runoff formation process at the Peat Bog hillslope and in the adjacent riparian zone. This lateral flow through the organic soil hillslope (Peat Bog) towards the stream occurred mainly as shallow subsurface flow in organic layers above the groundwater level (BMF and SSF), but water partly percolates to the shallow groundwater via vertical macropores as well . In contrast, the mineral soil hillslope (Podzol) was mostly dominated by vertical percolation. Lateral flow occurred only on short distances in the organic topsoil as biomat flow (BMF). The sorptive tracer Brilliant Blue FCF successfully stained flowpaths in the soil at both hillslopes, whereas the identification of soil staining patterns by the relatively conservative tracer Fluorescein was limited on organic soil profiles.

A millennial-scale record of Pb and Hg contamination in peatlands of the Sacramento-San Joaquin Delta of California, USA.

PubMed

Drexler, Judith Z; Alpers, Charles N; Neymark, Leonid A; Paces, James B; Taylor, Howard E; Fuller, Christopher C

2016-05-01

In this paper, we provide the first record of millennial patterns of Pb and Hg concentrations on the west coast of the United States. Peat cores were collected from two micro-tidal marshes in the Sacramento-San Joaquin Delta of California. Core samples were analyzed for Pb, Hg, and Ti concentrations and dated using radiocarbon and (210)Pb. Pre-anthropogenic concentrations of Pb and Hg in peat ranged from 0.60 to 13.0μgg(-1)and from 6.9 to 71ngg(-1), respectively. For much of the past 6000+ years, the Delta was free from anthropogenic pollution, however, beginning in ~1425CE, Hg and Pb concentrations, Pb/Ti ratios, Pb enrichment factors (EFs), and HgEFs all increased. Pb isotope compositions of the peat suggest that this uptick was likely caused by smelting activities originating in Asia. The next increases in Pb and Hg contamination occurred during the California Gold Rush (beginning ~1850CE), when concentrations reached their highest levels (74μgg(-1) Pb, 990ngg(-1) Hg; PbEF=12 and HgEF=28). Lead concentrations increased again beginning in the ~1920s with the incorporation of Pb additives in gasoline. The phase-out of lead additives in the late 1980s was reflected in changes in Pb isotope ratios and reductions in Pb concentrations in the surface layers of the peat. The rise and subsequent fall of Hg contamination was also tracked by the peat archive, with the highest Hg concentrations occurring just before 1963CE and then decreasing during the post-1963 period. Overall, the results show that the Delta was a pristine region for most of its ~6700-year existence; however, since ~1425CE, it has received Pb and Hg contamination from both global and regional sources. Published by Elsevier B.V.

Exploring 222Rn as a tool for tracing groundwater inflows from eskers and moraines into slope peatlands of the Amos region of Quebec, Canada.

PubMed

Berthot, Laureline; Pinti, Daniele L; Larocque, Marie; Gagné, Sylvain; Ferlatte, Miryane; Cloutier, Vincent

2016-11-01

Peatlands can play an important role in the hydrological dynamics of a watershed. However, interactions between groundwater and peat water remain poorly understood. Here, we present results of an exploratory study destined to test radon ( 222 Rn) as a potential tracer of groundwater inflows from fluvioglacial landform aquifers to slope peatlands in the Amos region of Quebec, Canada. 222 Rn occurs in groundwater but is expected to be absent from peat water because of its rapid degassing to the atmosphere. Any 222 Rn activity detected in peat water should therefore derive from groundwater inflow. 222 Rn activity was measured in groundwater from municipal, domestic wells and newly drilled and instrumented piezometers from the Saint-Mathieu-Berry and Barraute eskers (n = 9), from the Harricana Moraine (n = 4), and from the fractured bedrock (n = 3). Forty measurements of 222 Rn activity were made from piezometers installed in five slope peatlands, along six transects oriented perpendicular to the fluvioglacial deposits. The relationship between 222 Rn and total dissolved solids (TDS) measured in water from the mineral deposits underlying the peat layer suggests that 222 Rn is introduced by lateral inflow from eskers and moraine together with salinity. This input is then diluted by peat water, depleted in both TDS and 222 Rn. The fact that a relationship between TDS and 222 Rn is visible calls for a continuous inflow of groundwater from lateral eskers/moraines, being 222 Rn rapidly removed from the system by radioactive decay. Although more research is required to improve the sampling and tracing techniques, this work shows the potential of 222 Rn tracer to identify groundwater inflow areas from granular aquifers found in eskers and moraines to slope peatlands. Copyright © 2016 Elsevier Ltd. All rights reserved.

A millennial-scale record of Pb and Hg contamination in peatlands of the Sacramento-San Joaquin Delta of California, USA

USGS Publications Warehouse

Drexler, Judith; Alpers, Charles N.; Neymark, Leonid; Paces, James B.; Taylor, Howard E.; Fuller, Christopher C.

2016-01-01

In this paper, we provide the first record of millennial patterns of Pb and Hg concentrations on the west coast of the United States. Peat cores were collected from two micro-tidal marshes in the Sacramento-San Joaquin Delta of California. Core samples were analyzed for Pb, Hg, and Ti concentrations and dated using radiocarbon, 210Pb, and 137Cs. Pre-anthropogenic concentrations of Pb and Hg in peat ranged from 0.60 to 13.0 µg g-1and from 6.9 to 71 ng g-1, respectively. For much of the past 6000+ years, the Delta was free from anthropogenic pollution, however, beginning in ~1425 CE, Hg and Pb concentrations, Pb/Ti ratios, Pb enrichment factors (EFs), and HgEFs all increased. Pb isotope compositions of the peat suggest that this uptick was likely caused by smelting activities originating in Asia. The next increases in Pb and Hg contamination occurred during the California Gold Rush (beginning ~1850 CE), when concentrations reached their highest levels (74 µg g-1 Pb, 990 ng g-1 Hg; PbEF = 12 and HgEF = 28). Lead concentrations increased again beginning in the ~1920s with the incorporation of Pb additives in gasoline. The phase-out of lead additives in the late 1980s was reflected in Pb isotope ratios and reductions in Pb concentrations in the surface layers of the peat. The rise and fall of Hg contamination was also tracked by the peat archive, with the highest Hg concentrations occurring just before 1963 CE and then decreasing during the post-1963 period. Overall, the results show that the Delta was a pristine region for most of its ~6700-year existence; however, since ~1425 CE, it has received Pb and Hg contamination from both global and regional sources.

Paleobotany and palynology of the Bristol Hill Coal Member (Bond Formation) and Friendsville Coal Member (Mattoon Formation) of the Illinois Basin (Upper Pennsylvanian)

USGS Publications Warehouse

Willard, D.A.; Phillips, T.L.

1993-01-01

Late Pennsylvanian coal swamps of the Illinois Basin were dominated by Psarnius tree ferns with a spatially heterogeneous distribution of medullosan pteridosperms (subdominant), calamites, sigillarian lycopsids, and cordaites. Miospore and coal-ball plant assemblages from the Missourian-age Bristol Hill Coal Member (Mattoon Formation) of southeastern Illinois were quantified to analyze vegetational patterns in Late Pennsylvanian peat swamps and to compare vegetational composition of the coals. -from Authors

Landscape analysis of nutrient-enriched margins (lagg) in ombrotrophic peatlands.

PubMed

Langlois, Mélanie N; Price, Jonathan S; Rochefort, Line

2015-02-01

Scientific knowledge of the wet zone - the lagg - that tends to form at the edge of ombrotrophic peatlands is surprisingly limited. In this study, we aim to improve the understanding of the ecohydrological functions of this transition by describing the form and abiotic controls of the laggs and margins of bog peatlands. Data collected in wells and piezometers along 10 transects (within 6 bogs), of the New Brunswick Eastern Lowlands are used to analyse the hydraulic and hydrochemical gradients, while airborne LiDAR data provides new insight on the geomorphology and the vegetation patterns of the bog-lagg-mineral transition zone. Based on their geomorphic character, the study transects are placed into 2 categories: confined and unconfined. Laggs of confined transition are found in a topographic depression, between the bog and a mineral slope >1%, while laggs of unconfined transitions are adjacent to a flat (≤1%) or receding mineral slope (sloping away from the lagg). Water level (4 ± 9 cm vs. -3 ± 9 cm), pH (4.8 ± 0.9 vs. 4.2 ± 0.4), electrical conductivity (ECcorr) (105 ± 52 μS cm(-1) vs. 52 ± 28 μS cm(-1)) and peat depth (55 ± 9 cm vs. 30 ± 9 cm) are found to be higher, respectively, for the confined laggs than for the unconfined. Saturated hydraulic conductivity (Ksat) of the lagg's upper peat layer resembles that of bog environments, but quickly reduces with depth, impeding vertical water flow. The greatest abiotic control of the lagg appears to be topography, which affects water flow rates and direction, thus water chemistry, nutrient transport and availability, hence vegetation characteristics. Our results suggest that the features of the transition zone that include the lagg, influence the quantity and variability of water within the adjacent peatland, and should be considered as integral part of the peatland complex. Copyright © 2014 Elsevier B.V. All rights reserved.

Paleoenvironmental analyses of an organic deposit from an erosional landscape remnant, Arctic Coastal Plain of Alaska

USGS Publications Warehouse

Eisner, Wendy R.; Bockheim, James G.; Hinkel, Kenneth M.; Brown, Thomas A.; Nelson, Frederick E.; Peterson, Kim M.; Jones, Benjamin M.

2005-01-01

The dominant landscape process on the Arctic Coastal Plain of northern Alaska is the formation and drainage of thaw lakes. Lakes and drained thaw-lake basins account for approximately 75% of the modern surface expression of the Barrow Peninsula. The thaw-lake cycle usually obliterates lacustrine or peat sediments from previous cycles, which could otherwise be used for paleoecological reconstruction of long-term landscape and vegetation changes. Several possible erosional remnants of a former topographic surface that predates the formation of the thaw lakes have been tentatively identified. These remnants are characterized by a higher elevation, a thick organic layer with very high ground ice content in the upper permafrost and a plant community somewhat atypical of the region. Ten soil cores were collected from one site, and one core was intensively sampled for soil organic carbon content, pollen analysis and 14C dating. The lowest level of the organic sediments represents the earliest phase of plant growth and dates to ca. 9000 cal BP. Palynological evidence indicates the presence of mesic shrub tundra (including sedge, birch, willow and heath vegetation), and microfossil indicators point to wetter eutrophic conditions during this period. Carbon accumulation was rapid due to high net primary productivity in a relatively nutrient-rich environment. These results are interpreted as the local response to ameliorating climate during the early Holocene. The middle Holocene portion of the record contains an unconformity, indicating that between 8200 and 4200 cal BP sediments were eroded from the site, presumably in response to wind activity during a drier period centered around 4500 cal BP. The modern vegetation community of the erosional remnant was established after 4200 cal BP and peat growth resumed. During the late Holocene, carbon accumulation rates (CARs) were greatly reduced in response to the combined effects of declining productivity associated with climatic cooling, and increased nutrient stress as paludification and permafrost aggradation sequestered mineral nutrients.

Paleoenvironmental analyses of an organic deposit from an erosional landscape remnant, Arctic Coastal Plain of Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisner, W R; Bockheim, J G; Hinkel, K M

2005-01-02

The dominant landscape process on the Arctic Coastal Plain of northern Alaska is the formation and drainage of thaw lakes. Lakes and drained thaw lake basins account for approximately 75% of the modern surface expression of the Barrow Peninsula. The thaw lake cycle usually obliterates lacustrine or peat sediments from previous cycles which could otherwise be used for paleoecological reconstruction of long-term landscape and vegetation changes. Several possible erosional remnants of a former topographic surface that predates the formation of the thaw lakes have been tentatively identified. These remnants are characterized by a higher elevation, a thick organic layer withmore » very high ground ice content in the upper permafrost, and a plant community somewhat atypical of the region. Ten soil cores were collected from one site, and one core was intensively sampled for soil organic carbon content, pollen analysis, and {sup 14}C dating. The lowest level of the organic sediments represents the earliest phase of plant growth and dates to ca. 9000 cal BP. Palynological evidence indicates the presence of mesic shrub tundra (including sedge, birch, willow, and heath vegetation); and microfossil indicators point to wetter eutrophic conditions during this period. Carbon accumulation was rapid due to high net primary productivity in a relatively nutrient-rich environment. These results are interpreted as the local response to ameliorating climate during the early Holocene. The middle Holocene portion of the record contains an unconformity, indicating that between 8200 and 4200 cal BP sediments were eroded from the site, presumably in response to wind activity during a drier period centered around 4500 cal BP. The modern vegetation community of the erosional remnant was established after 4200 cal BP, and peat growth resumed. During the late Holocene, carbon accumulation rates were greatly reduced in response to the combined effects of declining productivity associated with climatic cooling, and increased nutrient stress as paludification and permafrost aggradation sequestered mineral nutrients.« less

Anthropogenic degradation of mountainous raised bogs. Case study of the Polish Carpathians

NASA Astrophysics Data System (ADS)

Lajczak, Adam

2016-04-01

Publications on the human impact on peat bogs pay a lot of attention to peat erosion, peat burning and changes in the physical and chemical properties of peat deposits that indicate pollution in the environment, but a more detailed analysis of current changes in the peat bog relief as a result of peat deposit extraction and drying is omitted. Compared to other areas of the world, the level of knowledge on anthropogenic changes in the relief of peat bogs in some areas of Poland may be considered advanced. This applies not only to peat bogs in northern Poland but also southern Poland, where peat bogs in the Carpathians and the Sudetes are also found. The best analyzed peat bogs in southern Poland are the raised bogs in the Orawsko-Nowotarska Basin (Western Carpathians) and in valleys in the Bieszczady Mts. (Eastern Carpathians). Both areas are impacted by deep precipitation shadow. The purpose of this paper is: (1) to assess the rate of shrinkage in the surface area of peat domes in the mentioned areas, (2) to describe the rate of growth in the surface area of older and younger post-peat areas, (3) to explain current changes in peat bogs morphology, (4) to explain changes in water retention in peat deposit, (5) to separate phases in peat bogs relief changes. With that in mind, the direction and rate of change of landforms typical of younger post-peat areas, such as peat extraction scarps, post-extraction hollows, drainage systems including ditches and regulated stream channels, were analyzed. A special emphasis was placed on the period of time when the restoration of such areas has taken place. The paper is based on an analysis of maps produced over the last 230 years as well as on aerial photographs taken since 1965 and on LiDAR data. Fieldwork included the geomorphological and hydrographic mapping of specified landforms within peat bogs using GPS methods. In period prior to human activity peat domes were larger than today and were surrounded by lagg fens and were drained by meandering streams. In period prior to the end of peat extraction and drying the amount of area lost by the peat dome and former wetland fringe can be identified in terms of older and younger post-peat areas. Stream channels in the general area have been regulated and drainage ditches dug. Partial or full peat extraction taking place primarily in the domes' fringe zone has produced major changes in peat bog relief and has substantially reduced peat bog water content. The increased density of drainage ditches in the area surrounding the remnants of peat domes has led to further drying of the peat bogs. An unintended consequence of stream regulation are shallower and wider channels that evolve into braided channels with a local tendency to aggradate material. The current stage of peat bogs development is their restoration which started when peat extraction had been halted in most peat bogs and drainage ditch maintenance had been abandoned.

Geophysical imaging and thermal modeling of subsurface morphology and thaw evolution of discontinuous permafrost

NASA Astrophysics Data System (ADS)

McClymont, Alastair F.; Hayashi, Masaki; Bentley, Laurence R.; Christensen, Brendan S.

2013-09-01

our current understanding of permafrost thaw in subarctic regions in response to rising air temperatures, little is known about the subsurface geometry and distribution of discontinuous permafrost bodies in peat-covered, wetland-dominated terrains and their responses to rising temperature. Using electrical resistivity tomography, ground-penetrating radar profiling, and thermal-conduction modeling, we show how the land cover distributions influence thawing of discontinuous permafrost at a study site in the Northwest Territories, Canada. Permafrost bodies in this region occur under forested peat plateaus and have thicknesses of 5-13 m. Our geophysical data reveal different stages of thaw resulting from disturbances within the active layer: from widening and deepening of differential thaw features under small frost-table depressions to complete thaw of permafrost under an isolated bog. By using two-dimensional geometric constraints derived from our geophysics profiles and meteorological data, we model seasonal and interannual changes to permafrost distribution in response to contemporary climatic conditions and changes in land cover. Modeling results show that in this environment (1) differences in land cover have a strong influence on subsurface thermal gradients such that lateral thaw dominates over vertical thaw and (2) in accordance with field observations, thaw-induced subsidence and flooding at the lateral margins of peat plateaus represents a positive feedback that leads to enhanced warming along the margins of peat plateaus and subsequent lateral heat conduction. Based on our analysis, we suggest that subsurface energy transfer processes (and feedbacks) at scales of 1-100 m have a strong influence on overall permafrost degradation rates at much larger scales.

Spatial Analysis of Soil Subsidence in Peat Meadow Areas in Friesland in Relation to Land and Water Management, Climate Change, and Adaptation

NASA Astrophysics Data System (ADS)

Brouns, Karlijn; Eikelboom, Tessa; Jansen, Peter C.; Janssen, Ron; Kwakernaak, Cees; van den Akker, Jan J. H.; Verhoeven, Jos T. A.

2015-02-01

Dutch peatlands have been subsiding due to peat decomposition, shrinkage and compression, since their reclamation in the 11th century. Currently, subsidence amounts to 1-2 cm/year. Water management in these areas is complex and costly, greenhouse gases are being emitted, and surface water quality is relatively poor. Regional and local authorities and landowners responsible for peatland management have recognized these problems. In addition, the Netherlands Royal Meteorological Institute predicts higher temperatures and drier summers, which both are expected to enhance peat decomposition. Stakeholder workshops have been organized in three case study areas in the province of Friesland to exchange knowledge on subsidence and explore future subsidence rates and the effects of land use and management changes on subsidence rates. Subsidence rates were up to 3 cm/year in deeply drained parcels and increased when we included climate change in the modeling exercises. This means that the relatively thin peat layers in this province (ca 1 m) would shrink or even disappear by the end of the century when current practices continue. Adaptation measures were explored, such as extensive dairy farming and the production of new crops in wetter conditions, but little experience has been gained on best practices. The workshops have resulted in useful exchange of ideas on possible measures and their consequences for land use and water management in the three case study areas. The province and the regional water board will use the results to develop land use and water management policies for the next decades.

The Cultivation of Arabidopsis for Experimental Research Using Commercially Available Peat-Based and Peat-Free Growing Media

PubMed Central

Drake, Tiffany; Keating, Mia; Summers, Rebecca; Yochikawa, Aline; Pitman, Tom

2016-01-01

Experimental research involving Arabidopsis thaliana often involves the quantification of phenotypic traits during cultivation on compost or other growing media. Many commercially-available growing media contain peat, but peat extraction is not sustainable due to its very slow rate of formation. Moreover, peat extraction reduces peatland biodiversity and releases stored carbon and methane into the atmosphere. Here, we compared the experimental performance of Arabidopsis on peat-based and several types of commercially-available peat-free growing media (variously formed from coir, composted bark, wood-fibre, and domestic compost), to provide guidance for reducing peat use in plant sciences research with Arabidopsis. Arabidopsis biomass accumulation and seed yield were reduced by cultivation on several types of peat-free growing media. Arabidopsis performed extremely poorly on coir alone, presumably because this medium was completely nitrate-free. Some peat-free growing media were more susceptible to fungal contamination. We found that autoclaving of control (peat-based) growing media had no effect upon any physiological parameters that we examined, compared with non-autoclaved control growing media, under our experimental conditions. Overall, we conclude that Arabidopsis performs best when cultivated on peat-based growing media because seed yield was almost always reduced when peat-free media were used. This may be because standard laboratory protocols and growth conditions for Arabidopsis are optimized for peat-based media. However, during the vegetative growth phase several phenotypic traits were comparable between plants cultivated on peat-based and some peat-free media, suggesting that under certain circumstances peat-free media can be suitable for phenotypic analysis of Arabidopsis. PMID:27088495

Tsunami recurrence in the eastern Alaska-Aleutian arc: A Holocene stratigraphic record from Chirikof Island, Alaska

USGS Publications Warehouse

Nelson, Alan R.; Briggs, Richard; Dura, Tina; Engelhart, Simon E.; Gelfenbaum, Guy; Bradley, Lee-Ann; Forman, S.L.; Vane, Christopher H.; Kelley, K.A.

2015-01-01

Despite the role of the Alaska-Aleutian megathrust as the source of some of the largest earthquakes and tsunamis, the history of its pre–twentieth century tsunamis is largely unknown west of the rupture zone of the great (magnitude, M 9.2) 1964 earthquake. Stratigraphy in core transects at two boggy lowland sites on Chirikof Island’s southwest coast preserves tsunami deposits dating from the postglacial to the twentieth century. In a 500-m-long basin 13–15 m above sea level and 400 m from the sea, 4 of 10 sandy to silty beds in a 3–5-m-thick sequence of freshwater peat were probably deposited by tsunamis. The freshwater peat sequence beneath a gently sloping alluvial fan 2 km to the east, 5–15 m above sea level and 550 m from the sea, contains 20 sandy to silty beds deposited since 3.5 ka; at least 13 were probably deposited by tsunamis. Although most of the sandy beds have consistent thicknesses (over distances of 10–265 m), sharp lower contacts, good sorting, and/or upward fining typical of tsunami deposits, the beds contain abundant freshwater diatoms, very few brackish-water diatoms, and no marine diatoms. Apparently, tsunamis traveling inland over low dunes and boggy lowland entrained largely freshwater diatoms. Abundant fragmented diatoms, and lake species in some sandy beds not found in host peat, were probably transported by tsunamis to elevations of >10 m at the eastern site. Single-aliquot regeneration optically stimulated luminescence dating of the third youngest bed is consistent with its having been deposited by the tsunami recorded at Russian hunting outposts in 1788, and with the second youngest bed being deposited by a tsunami during an upper plate earthquake in 1880. We infer from stratigraphy, 14C-dated peat deposition rates, and unpublished analyses of the island’s history that the 1938 tsunami may locally have reached an elevation of >10 m. As this is the first record of Aleutian tsunamis extending throughout the Holocene, we cannot estimate source earthquake locations or magnitudes for most tsunami-deposited beds. We infer that no more than 3 of the 23 possible tsunamis beds at both sites were deposited following upper plate faulting or submarine landslides independent of megathrust earthquakes. If so, the Semidi segment of the Alaska-Aleutian megathrust near Chirikof Island probably sent high tsunamis southward every 180–270 yr for at least the past 3500 yr.                   

Eutrophic mire, its characteristics and modern conditions of peat genesis

NASA Astrophysics Data System (ADS)

Inisheva, L. I.; Golubina, O. A.; Zaplatnikova, Yu. D.; Dubrovskaya, L. I.

2009-04-01

The study of structure functional organization of Siberian mire ecosystems is the base of after-effects influence of their reclamation on global changes of biosphere. The aim of this investigation is to study the structure functional organization of eutrophic mire ecosystem "Tagan". Peat deposit "Tagan" (West Siberia, 20 kilometers near Tomsk) is situated on the second flood-plain terrace of the river Tom of ancient flow channel. Maximum power of peat deposit is 9.3 meters. Subsoil is made up from sand, more seldom from loamy sand and loam. Eutrophic vegetation covers almost the whole mire. It is presented by woody sedge, sedge, sedge-moss and grass undershrub phytocenoses. The oligotrophic vegetation is presented by Sphagnum pine cotton-grass phytocenosis. There were organized three observation points on the mire in 2007. They watched dynamics of hydrothermic, redox, biological, hydrochemical regimes. There were studied physicochemical properties at given points. Peats with normal ash basically refer to grass, woody grass group of lowland type. They are characterized by high degree of decomposition which is increased down deposit. Group composition of organic matters of investigated peats showed that bitumen content in peat changes from 1.4 to 3.56%, and humid acids content is within the limits of 16.67 - 44.34 %. Water-soluble and hardly-hydrolyzed matters are contained in quantity of 19.04 - 49.76% of the whole dry peat mass. The overall nitrogen content changes within the limits of 1.76 - 3.52%. It is presented mainly by fraction of unhydrolyzed nitrogen (72.07 - 95.67% of the whole nitrogen). Highly-hydrolyzed nitrogen is the most available reserve of mineral compound of nitrogen and its content changes within the limits of 0.18 - 4.79 of the overall nitrogen. 2008 year is characterized as an average year at conditions of moistening and heat providing. Investigations, made during this year, revealed the following results. Bog waters were kept at a surface level of 20 - 69cm in summer. Peat deposit heating up to 10˚ C was observed at a depth of 120cm. Oxidizing conditions are traced up to 40 - 60cm deep. There is gradual change into restoring conditions deep in peat deposit. Very reduction conditions are observed at a depth of 60cm. Weather conditions of 2008 year were favorable for biological processes activation. In the result of their manifestation hydrochemical composition of bog waters was formed. First of all, one should pay attention to weak alkaline reaction of bog waters. Calcium content in bog waters changes from 70.2 to 150.9 mg/l. One may state calcium removal from peat deposit of eutrophic mire into an outfall. The latter is the river which is flowing along the mire. Magnesium concentration in bog waters changed within the limits of 8.5 - 42.5 mg/l. It is important to note high content of iron in individual months - up to 17.8 mg/l. Organic matters content in bog waters, which are presented by humid acids (HA) and fulvic acids (FA), is HA 3.4 - 24.65 mg/l, FA 11.0 - 58.3 mg/l. Let's, first of all, examine dynamics of individual components in bog waters. Thus, content of calcium, water-soluble carbon, and fulvic acids naturally increased in July, when it was marked combination of high temperature and minor precipitation. Active iron in bog waters had the highest concentration in spring which had gradually decreased by September (from 18 and 8 mg/l to 0.1 mg/l). Preliminary obtained results reveal bog drainage occurring at present. It is followed also from the fact that there are favorable redox conditions in a meter layer of peat deposit and high degree of peats decomposition. The examination of dynamics of hydrothermic, biological and hydrochemical regimes also is evidence of biological processes activity in eutrophic mire "Tagan". This fact, in its turn, influences on hydrochemical compound formation of bog waters.

SPRUCE Plant-Available Nutrients Assessed with Ion-Exchange Resins in Experimental Plots, Beginning in 2013

DOE Data Explorer

Iversen, C. M. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A; Latimer, J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A; Burnham, A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A; Brice, D. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A; Childs, J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A; Vander Stel, H. M. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A

2017-01-01

This data set consists of observations of plant-available nutrients assessed using ion-exchange resin capsules incubated serially in aerobic and anaerobic peat layers beginning in 2013 in the SPRUCE experimental plots at four depths in hummock microtopography and two depths in hollow microtopography. Data will be periodically added to until the conclusion of the SPRUCE experiment.

A Novel Surface Structure Consisting of Contact-active Antibacterial Upper-layer and Antifouling Sub-layer Derived from Gemini Quaternary Ammonium Salt Polyurethanes.

PubMed

He, Wei; Zhang, Yi; Li, Jiehua; Gao, Yunlong; Luo, Feng; Tan, Hong; Wang, Kunjie; Fu, Qiang

2016-08-26

Contact-active antibacterial surfaces play a vital role in preventing bacterial contamination of artificial surfaces. In the past, numerous researches have been focused on antibacterial surfaces comprising of antifouling upper-layer and antibacterial sub-layer. In this work, we demonstrate a reversed surface structure which integrate antibacterial upper-layer and antifouling sub-layer. These surfaces are prepared by simply casting gemini quaternary ammonium salt waterborne polyurethanes (GWPU) and their blends. Due to the high interfacial energy of gemini quaternary ammonium salt (GQAS), chain segments containing GQAS can accumulate at polymer/air interface to form an antibacterial upper-layer spontaneously during the film formation. Meanwhile, the soft segments composed of polyethylene glycol (PEG) formed the antifouling sub-layer. Our findings indicate that the combination of antibacterial upper-layer and antifouling sub-layer endow these surfaces strong, long-lasting antifouling and contact-active antibacterial properties, with a more than 99.99% killing efficiency against both gram-positive and gram-negative bacteria attached to them.

A Novel Surface Structure Consisting of Contact-active Antibacterial Upper-layer and Antifouling Sub-layer Derived from Gemini Quaternary Ammonium Salt Polyurethanes

PubMed Central

He, Wei; Zhang, Yi; Li, Jiehua; Gao, Yunlong; Luo, Feng; Tan, Hong; Wang, Kunjie; Fu, Qiang

2016-01-01

Contact-active antibacterial surfaces play a vital role in preventing bacterial contamination of artificial surfaces. In the past, numerous researches have been focused on antibacterial surfaces comprising of antifouling upper-layer and antibacterial sub-layer. In this work, we demonstrate a reversed surface structure which integrate antibacterial upper-layer and antifouling sub-layer. These surfaces are prepared by simply casting gemini quaternary ammonium salt waterborne polyurethanes (GWPU) and their blends. Due to the high interfacial energy of gemini quaternary ammonium salt (GQAS), chain segments containing GQAS can accumulate at polymer/air interface to form an antibacterial upper-layer spontaneously during the film formation. Meanwhile, the soft segments composed of polyethylene glycol (PEG) formed the antifouling sub-layer. Our findings indicate that the combination of antibacterial upper-layer and antifouling sub-layer endow these surfaces strong, long-lasting antifouling and contact-active antibacterial properties, with a more than 99.99% killing efficiency against both gram-positive and gram-negative bacteria attached to them. PMID:27561546

Thermodynamic constrains on the flux of organic matter through a peatland ecosystem

NASA Astrophysics Data System (ADS)

Worrall, Fred; Moody, Catherine; Clay, Gareth; Kettridge, Nick; Burt, Tim

2017-04-01

The transformations and transitions of organic matter into, through and out of a peatland ecosystem must obey the 2nd law of thermodynamics. Beer and Blodau (Geochimica Cosmochimica Acta, 2007, 71, 12, 2989-3002) showed that the evolution of CH4 in peatlands was constrained by equilibrium occurring at depth in the peat as the pore water became a closed system. However, that study did not consider the transition in the solid components of the organic matter flux through the entire ecosystem. For this study, organic matter samples were taken from each organic matter reservoir and fluvial transfer pathway and analysed the samples by elemental analysis and bomb calorimetry. The samples analysed were: above- and below-ground biomass, heather, mosses, sedges, plant litter layer, peat soil, and monthly samples of particulate and dissolved organic matter. All organic matter samples were taken from a 100% peat catchment within Moor House National Nature Reserve in the North Pennines, UK, and collected samples were compared to standards of lignin, cellulose, and plant protein. It was possible to calculate ∆H_f^OM ∆S_f^OM and ∆G_f^OM for each of the samples and standards. By assuming that each thermodynamic property can be expressed per g C and that any increase in ∆G_f^OM can be balanced by the production of CO2, DOM or CH4 then it is possible to predict the consequences of the fixation of 1 g of carbon in a peatland soil. The value of ∆G_f^OMincreases from glucose to components of the biomass: 1g of C fixed as glucose by photosynthesis would result in 0.68 g C as biomass and 0.32 g C as CO2. The transition from biomass to litter could occur spontaneously but the transition from surface to 1m depth in the peat profile would release 0.18 g C as CO2 per 1 g of carbon entering the peat profile. Therefore, for every 1 g of carbon fixed from photosynthesis then 0.44g of C would be released as CO2 and 0.54 g C would be present at 1 m depth. Alternatively, if DOM only were released in transition down the peat profile then for every 1 g of carbon fixed by photosynthesis 0.32 g C would be released as CO2 and 0.22 g C would be lost as DOM and leaving 0.46 g C as residual peat at 1m depth. If the variation in ∆G_f^OM of the DOM were considered then for every 1 g of C produced as DOM then between 0 and 0.57g C would be lost as CO2. At median value of DOM loss then for every 1g of carbon fixed as photosynthesis 0.39 g C would be lost as CO2 and 0.15 g lost as DOM with 0.46 g C as residual peat. Alternatively, if CH4 only were released down the soil profile then no organic matter would be left in the peat profile, i.e. CH4 is not an efficient method of transferring Gibbs free energy. The measured carbon budget for this catchment is that 1 g C fixed as photosynthesis resulted in 0.42 g C as CO2; 0.29 g C as DOM; 0.04 g C as CH4 and 0.24 g C as residual peat at 1m depth.

Dissolved organic carbon and major and trace elements in peat porewater of sporadic, discontinuous, and continuous permafrost zones of western Siberia

NASA Astrophysics Data System (ADS)

Raudina, Tatiana V.; Loiko, Sergey V.; Lim, Artyom G.; Krickov, Ivan V.; Shirokova, Liudmila S.; Istigechev, Georgy I.; Kuzmina, Daria M.; Kulizhsky, Sergey P.; Vorobyev, Sergey N.; Pokrovsky, Oleg S.

2017-07-01

Mobilization of dissolved organic carbon (DOC) and related trace elements (TEs) from the frozen peat to surface waters in the permafrost zone is expected to enhance under ongoing permafrost thaw and active layer thickness (ALT) deepening in high-latitude regions. The interstitial soil solutions are efficient tracers of ongoing bio-geochemical processes in the critical zone and can help to decipher the intensity of carbon and metals migration from the soil to the rivers and further to the ocean. To this end, we collected, across a 640 km latitudinal transect of the sporadic to continuous permafrost zone of western Siberia peatlands, soil porewaters from 30 cm depth using suction cups and we analyzed DOC, dissolved inorganic carbon (DIC), and 40 major elements and TEs in 0.45 µm filtered fraction of 80 soil porewaters. Despite an expected decrease in the intensity of DOC and TE mobilization from the soil and vegetation litter to the interstitial fluids with the increase in the permafrost coverage and a decrease in the annual temperature and ALT, the DOC and many major and trace elements did not exhibit any distinct decrease in concentration along the latitudinal transect from 62.2 to 67.4° N. The DOC demonstrated a maximum of concentration at 66° N, on the border of the discontinuous/continuous permafrost zone, whereas the DOC concentration in peat soil solutions from the continuous permafrost zone was equal to or higher than that in the sporadic/discontinuous permafrost zone. Moreover, a number of major (Ca, Mg) and trace (Al, Ti, Sr, Ga, rare earth elements (REEs), Zr, Hf, Th) elements exhibited an increasing, not decreasing, northward concentration trend. We hypothesize that the effects of temperature and thickness of the ALT are of secondary importance relative to the leaching capacity of peat, which is in turn controlled by the water saturation of the peat core. The water residence time in peat pores also plays a role in enriching the fluids in some elements: the DOC, V, Cu, Pb, REEs, and Th were a factor of 1.5 to 2.0 higher in mounds relative to hollows. As such, it is possible that the time of reaction between the peat and downward infiltrating waters essentially controls the degree of peat porewater enrichments in DOC and other solutes. A 2° northward shift in the position of the permafrost boundaries may bring about a factor of 1.3 ± 0.2 decrease in Ca, Mg, Sr, Al, Fe, Ti, Mn, Ni, Co, V, Zr, Hf, Th, and REE porewater concentration in continuous and discontinuous permafrost zones, and a possible decrease in DOC, specific ultraviolet absorbency (SUVA), Ca, Mg, Fe, and Sr will not exceed 20 % of their current values. The projected increase in ALT and vegetation density, northward migration of the permafrost boundary, or the change of hydrological regime is unlikely to modify chemical composition of peat porewater fluids larger than their natural variations within different micro-landscapes, i.e., within a factor of 2. The decrease in DOC and metal delivery to small rivers and lakes by peat soil leachate may also decrease the overall export of dissolved components from the continuous permafrost zone to the Arctic Ocean. This challenges the current paradigm on the increase in DOC export from the land to the ocean under climate warming in high latitudes.

Environmental factors controlling fluxes of dimethyl sulfide in a New Hampshire fen

NASA Technical Reports Server (NTRS)

Demello, William Zamboni; Hines, Mark E.

1992-01-01

The major environmental factors controlling fluxes of dimethyl sulfide (DMS) in a Sphagnum-dominated peatland were investigated in a poor fen in New Hampshire. DMS emissions from the surface of the peatland varied greatly over 24 hours and seasonally. Maximum DMS emissions occurred in summer with minima in the late fall. Temperature was the major environmental factor controlling these variabilities. There was also some evidence that the changes in water table height might have contributed to the seasonable variability in DMS emission. The influence of the water table was greater during periods of elevated temperature. DMS and MSH were the most abundant dissolved volatile sulfur compound (VSC) in the surface of the water table. Concentrations of dissolved VSC's varied with time and space throughout the fen. Dissolved MDS, MSH, and OCS in the surface of the water table were supersaturated with respect to their concentrations in the atmosphere suggesting that the peat surface was a source of VSC's in the peatland. VCS in peatlands seemed to be produced primarily by microbial processes in the anoxic surface layers of the peat rich in organic matter and inorganic sulfide. Sphagnum mosses were not a direct source of VSC's. However, they increased transport of DMS from the peat surface to the atmosphere.

The carbon functional group budget of a peatland

NASA Astrophysics Data System (ADS)

Moody, Catherine; Worrall, Fred; Clay, Gareth; Apperley, David

2016-04-01

Organic matter samples were taken from each organic matter reservoir and fluvial flux found in a peatland and analysed by elemental analysis for carbon, hydrogen, nitrogen and oxygen content, and by 13C solid state nuclear magnetic resonance (NMR) for functional group composition. The samples analysed were: aboveground, belowground, heather, mosses and sedges, litter layer, four different depths from a peat core, and monthly samples of fluvial particulate and dissolved organic matter. All organic matter samples were taken from a 100% peat catchment within Moor House National Nature Reserve in the North Pennines, UK. The proportion of carbon atoms from each of the eight carbon functional groups (C-alkyl, N-alkyl/methoxyl C, O-alkyl, O2-alkyl/acetal C, aromatic/unsaturated C, phenolic C, aldehyde/ketone C and amide/carboxyl C) from each type of organic matter were combined with an existing carbon budget from the same site, to give a functional group carbon budget. The budget results show that the ecosystem is accumulating N-alkyl/methoxyl C, O-alkyl, O2-alkyl/acetal C and phenolic C groups, but losing C-alkyl, aromatic/unsaturated C, amide/carboxyl C and aldehyde/ketone C. Comparing the functional group compositions between the sampled organic matter pools shows that DOM arises from two distinct sources; from the peat itself and from a vegetation source.

Partitioning Carbon Dioxide Emission and Assessing Dissolved Organic Carbon Leaching of a Drained Peatland Cultivated with Pineapple at Saratok, Malaysia

PubMed Central

Lim Kim Choo, Liza Nuriati; Ahmed, Osumanu Haruna

2014-01-01

Pineapples (Ananas comosus (L.) Merr.) cultivation on drained peats could affect the release of carbon dioxide (CO2) into the atmosphere and also the leaching of dissolved organic carbon (DOC). Carbon dioxide emission needs to be partitioned before deciding on whether cultivated peat is net sink or net source of carbon. Partitioning of CO2 emission into root respiration, microbial respiration, and oxidative peat decomposition was achieved using a lysimeter experiment with three treatments: peat soil cultivated with pineapple, bare peat soil, and bare peat soil fumigated with chloroform. Drainage water leached from cultivated peat and bare peat soil was also analyzed for DOC. On a yearly basis, CO2 emissions were higher under bare peat (218.8 t CO2 ha/yr) than under bare peat treated with chloroform (205 t CO2 ha/yr), and they were the lowest (179.6 t CO2 ha/yr) under cultivated peat. Decreasing CO2 emissions under pineapple were attributed to the positive effects of photosynthesis and soil autotrophic activities. An average 235.7 mg/L loss of DOC under bare peat suggests rapid decline of peat organic carbon through heterotrophic respiration and peat decomposition. Soil CO2 emission depended on moderate temperature fluctuations, but it was not affected by soil moisture. PMID:25215335

Underwater Flow Visualization Methods in the Upper Layer of the Ocean.

DTIC Science & Technology

1981-05-22

AD-A107 919 NAVAL RESEARCH LAB WASHINGTON DC F/G 8/3 UNDERWATER FLOW VISUALIZATION METHODS IN T1E UPPER LAYER OF THE-ETC(U) AMAY 81 J R MCGRATH, C M...S.bOti1.) S. TYPE OF REPORT I PERIOD COVERED UNDERWATER FLOW VISUALIZATION METHODS Interim report on a continuingNRL problem. IN THE UPPER LAYER OF THE...56 UNDERWATER FLOW VISUALIZATION METHODS IN THE UPPER LAYER OF THE OCEAN 1. INTRODUCTION a) Purpose This report documents the

Earthquake-caused subsidence events of the Duck Flats at the eastern end of the Knik Arm, Alaska

NASA Astrophysics Data System (ADS)

Reeder, J. W.

2012-12-01

A 5 km NS-trending gas pipeline trench, excavated in 1984 across the Duck Flats of the eastern end of the Knik Arm about 50 km NE of Anchorage, Alaska, exposed two continuous buried peat horizons. Two bulk C-14 dates for the upper buried peat horizon were determined to be 790 ± 160 and 775 ± 170 ybp. The depth of this peat horizon varied from 1.0 to 1.8 m. The deeper paleopeat horizon had a single bulk C-14 date of 1190 ± 80 ybp and varied from 1.7 to greater than 2.4 m (depth of trench). A deeper third paleopeat horizon was confirmed in 2012 by hand auger, which was found at a depth of 3.7 m. Turbulent organic (principally grass) mixing with tidal silt and clay immediately above both of the trench paleopeat horizons is interpreted to reflect tsunami flooding. The March 27, 1964, earthquake caused recognized subsidence of up to 0.3 m at the southern end of the trench as based on tidal deposits above 1964 peats. This was caused by consolidation of Matanuska and Knik fluvial deposits immediately to the S and by some tectonic subsidence. The 1964 peat horizon was not recognized for the rest of the trench possibly because of poor near-surface winter exposures or more simply because the 1964 peat horizon is also part of the present surface. The existence of the above continuous paleopeat horizons is significant because they reflect subsidence events not expected with 1964-type megathrust subduction. In fact, the above paleopeat C-14 age dates correlate more with recognized earthquake events of the Castle Mountain fault, an intraplate fault 20 km to the NW, than with recognized 1964-type megathrust events. However, movements on regional crustal faults, such as the Castle Mountain fault, likely would not be enough to account for the large amounts of subsidence observed on the Duck Flats. Instead, these subsidence events probably reflect sudden tectonic movements of the Pacific plate beneath the North American plate in this region. The process would involve flat-slab subduction of the Yakutat microplate coupled to the Pacific plate. Such movements might have extended not only to, but possibly even combined at times with, 1964-type megathrust movements principally to the SE, as well as combined with movements of regional faults such as the Castle Mountain fault. The potential for such continental megathrust earthquakes should be included with any future earthquake hazard considerations for this region.

Bacillus cereus in free-stall bedding.

PubMed

Magnusson, M; Svensson, B; Kolstrup, C; Christiansson, A

2007-12-01

To increase the understanding of how different factors affect the bacterial growth in deep sawdust beds for dairy cattle, the microbiological status of Bacillus cereus and coliforms in deep sawdust-bedded free stalls was investigated over two 14-d periods on one farm. High counts of B. cereus and coliforms were found in the entire beds. On average, 4.1 log(10) B. cereus spores, 5.5 log(10) B. cereus, and 6.7 log(10) coliforms per gram of bedding could be found in the upper layers of the sawdust likely to be in contact with the cows' udders. The highest counts of B. cereus spores, B. cereus, and coliforms were found in the bedding before fresh bedding was added, and the lowest immediately afterwards. Different factors of importance for the growth of B. cereus in the bedding material were explored in laboratory tests. These were found to be the type of bedding, pH, and the type and availability of nutrients. Alternative bedding material such as peat and mixtures of peat and sawdust inhibited the bacterial growth of B. cereus. The extent of growth of B. cereus in the sawdust was increased in a dose-dependent manner by the availability of feces. Urine added to different bedding material raised the pH and also led to bacterial growth of B. cereus in the peat. In sawdust, a dry matter content greater than 70% was needed to lower the water activity to 0.95, which is needed to inhibit the growth of B. cereus. In an attempt to reduce the bacterial growth of B. cereus and coliforms in deep sawdust beds on the farm, the effect of giving bedding daily or a full replacement of the beds was studied. The spore count of B. cereus in the back part of the free stalls before fresh bedding was added was 0.9 log units lower in stalls given daily bedding than in stalls given bedding twice weekly. No effect on coliform counts was found. Replacement of the entire sawdust bedding had an effect for a short period, but by 1 to 2 mo after replacement, the counts of B. cereus spores in the beds had increased about 2 log units and were as high as they were before bed replacement. Therefore, free-stall management could, to a limited extent, reduce the content of B. cereus spores in the beds by daily bedding and entire bed replacement.

High-resolution mapping of ecosystem carbon storage and potential effects of permafrost thaw in periglacial terrain, European Russian Arctic

NASA Astrophysics Data System (ADS)

Hugelius, Gustaf; Virtanen, Tarmo; Kaverin, Dmitry; Pastukhov, Alexander; Rivkin, Felix; Marchenko, Sergey; Romanovsky, Vladimir; Kuhry, Peter

2011-09-01

This study describes detailed partitioning of phytomass carbon (C) and soil organic carbon (SOC) for four study areas in discontinuous permafrost terrain, Northeast European Russia. The mean aboveground phytomass C storage is 0.7 kg C m-2. Estimated landscape SOC storage in the four areas varies between 34.5 and 47.0 kg C m-2 with LCC (land cover classification) upscaling and 32.5-49.0 kg C m-2 with soil map upscaling. A nested upscaling approach using a Landsat thematic mapper land cover classification for the surrounding region provides estimates within 5 ± 5% of the local high-resolution estimates. Permafrost peat plateaus hold the majority of total and frozen SOC, especially in the more southern study areas. Burying of SOC through cryoturbation of O- or A-horizons contributes between 1% and 16% (mean 5%) of total landscape SOC. The effect of active layer deepening and thermokarst expansion on SOC remobilization is modeled for one of the four areas. The active layer thickness dynamics from 1980 to 2099 is modeled using a transient spatially distributed permafrost model and lateral expansion of peat plateau thermokarst lakes is simulated using geographic information system analyses. Active layer deepening is expected to increase the proportion of SOC affected by seasonal thawing from 29% to 58%. A lateral expansion of 30 m would increase the amount of SOC stored in thermokarst lakes/fens from 2% to 22% of all SOC. By the end of this century, active layer deepening will likely affect more SOC than thermokarst expansion, but the SOC stores vulnerable to thermokarst are less decomposed.

Relationships between sedimentation, depositional environments, and coal quality: upper Potomac coalfield, West Virginia and Maryland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jake, T.R.

1987-09-01

Evaluations were made of sedimentation patterns and depositional environments from approximately 450 core logs and 225 surface exposures in the Upper Potomac coalfield. The relationships between the clastic depositional facies and the distribution and quality of the Bakerstown and upper Freeport coals were also investigated. Data from 61 Bakerstown and 35 upper Freeport coal samples from selected cores indicate a change from uniform coal quality to highly variable coal quality when moving from related interchannel and bay-fill facies to channel, channel-fill, levee, and crevasse-splay facies. Areas of uniform coal quality range from 20-26% ash and 55-62% fixed carbon (weight percent,more » dry basis), whereas areas of highly variable coal quality range from 26-54% ash and 33-55% fixed carbon. The channel and related facies represent areas where increased fresh water was introduced into the topogenous swamp system, causing increased microbial degradation and the concentration of authigenic minerals within the peat material. These conditions, combined with the introduction of detrital minerals, resulted in areas of lower quality coal.« less

Evidence for late Holocene relative sea-level fall from reconnaissance stratigraphical studies in an area of earthquake-subsided intertidal deposits, Isla Chiloé, southern Chile

USGS Publications Warehouse

Frostick, L.E.; Steel, R.J.; Bartsch-Winkler, S.; Schmoll, H.R.

1993-01-01

At Río Pudeto and Quetalmahue, two estuaries along the northern shore of Isla Chiloé that subsided as much as 2 m in the great 1960 earthquake, reconnaissance stratigraphical studies reveal evidence of a regressive, nearshore marine sequence. The intertidal deposits include a peat-bearing, high-intertidal marsh sequence as thick as 1.4 m overlying shell- and foraminifera-bearing silt and clay layers presumed to represent a deeper water, low-intertidal environment.Stratigraphy indicates a relative sea-level fall since about 5000 years BP as evidenced by radiocarbon ages that constrain the peat-bearing sequences. Locally, low-intertidal silt and clay overlie high-intertidal peat layers, but such minor transgressions cannot be correlated from site to site. At Río Pudeto, the youngest foraminifera-bearing silt deposit is no younger than 1200 years BP. The youngest age of shells at Quetalmahue is about 2600 years BP. The oldest peat-bearing deposits that are not overlain by silt deposits are about 1350 years BP at Río Pudeto, and as old as 4900 years BP at Quetalmahue. At Río Pudeto, peat-bearing deposits, which are overlain by silt and clay, range in age from 760 to 5430 years BP, and at Quetalmahue from 290 to 5290 years BP. A beach terrace on the northwest coast of the Isla is estimated to have been emergent since 1150 + 130 years ago.Although some relatively abrupt transgressions may be due to sudden coseismic subsidence, data are not sufficient to document regional subsidence during individual plate-interface earthquakes. Seven earthquakes in south central Chile since 1520, especially those that occurred in 1575, 1737, and 1837, are thought to have been of a magnitude comparable to that of the 1960 earthquake. Although the sedimentological effects of the 1960 earthquake on the intertidal zone were dramatic, only limited evidence of possible historic earthquakes is found on Isla Chiloé and nearby islands; the ages and displacements of these earthquakes are indeterminable.Dead forests still mark some locations that subsided into the intertidal zone during the 1960 earthquake, particularly at Río Pudeto and southern coastal Chiloé. There is little evidence of post-1960 growth in any of these subsided areas. Tree-ring counts and tree-diameter measurements provide evidence that these trees survived the 1837 earthquake, and probably survived the 1737 earthquake, strongly suggesting that these earthquakes were of smaller magnitude than the 1960 event, or that the epicentre locations were further removed than the 1960 epicentre from Isla Chiloé, and that earthquake-induced relative sea-level changes differed from those occurring in 1960.

Peat bogs and their organic soils: Archives of atmospheric change and global environmentalsignificance (Philippe Duchaufour Medal Lecture)

NASA Astrophysics Data System (ADS)

Shotyk, William

2013-04-01

A bog is much more than a waterlogged ecosystem where organic matter accumulates as peat. Peatlands such as bogs represent a critical link between the atmosphere, hydrosphere, and biosphere. Plants growing at the surface of ombrotrophic bogs receive nutrients exclusively from the atmosphere. Despite the variations in redox status caused by seasonal fluctuations in depth to water table, the low pHof the waters, and abundance of dissolved organic matter, bogs preserve a remarkably reproducible history of atmospheric pollution, climate change, landscape evolution and human history. For example, peat cores from bogs in Europe and North America have provided detailed reconstructions of the changing rates and sources of Ag, Cd, Hg, Pb, Sb, and Tl, providing new insights into the geochemical cycles of these elements, including the massive perturbations induced by human activities beginning many thousands of years ago. Despite the low pH, and perhaps because of the abundance of dissolved organic matter, bogs preserve many silicate and aluminosilicate minerals which renders them valuable archives of atmospheric dust deposition and the climate changes which drive them. In the deeper, basal peat layers of the bog, in the minerotrophic zone where pore waters are affected bymineral-water interactions in the underlying and surrounding soils and sediments, peat serves as animportant link to the hydrosphere, efficiently removing from the imbibed groundwaters such trace elements as As, Cu, Mo, Ni, Se, V, and U. These removal processes, while incompletely understood, are so effective that measuring the dissolved fraction of trace elements in the pore waters becomes a considerable challenge even for the most sophisticated analytical laboratories. While the trace elements listed above are removed from groundwaters (along with P and S), elements such as Fe and Mn are added to the waters because of reductive dissolution, an important first step in the formation of lacustrine Fe and Mn nodules. While these important chemical reactions have taken place silently and imperceptibly over millenia acrossthe Earth wherever climate and water allow bogs to form, at the same time, peat bogs represent an important component of the biosphere and provide a home to many unique plants and animals, thereby contributing to the vast biodiversity found on Earth.

Applications of peat-based sorbents for removal of metals from water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, A.D.; Stack, E.M.; Eltayeb, S.

1995-12-31

The results reported in this paper are derived from one part of an ongoing investigation of peat sorption properties, in particular, the capacities of acid-treated peats to adsorb chromium, nickel, zinc, copper, and cadmium from water. Acid treatment was done to remove as much previously adsorbed metal as possible before testing. Four peat types were selected for study, two highly decomposed types (a woody, Taxodium-dominated peat from the Okefenokee Swamp of Georgia and a sedge-dominated, charcoal-rich peat from the Tamiami Trail region of Florida) and two less decomposed ones (a Sphagnum moss-dominated peat from Maine and a Nymphaea-dominated peat frommore » the Okefenokee Swamp of Georgia). Single metal and mixed metal solutions were tested in slurry experiments with each peat type. Solutions were analyzed using a Perkin-Elmer model 305B Flame Atomic Absorption Spectrophotometer. In single metal tests, chromium and copper tended to be adsorbed to a greater extent than the other metals. Three of the peats were found to be capable of adsorbine more copper ions than zince ions, while a fourth type adsorbed approximately the same amounts of each. Degree of decomposition of the peats tended to affect sorption properties for certain metals. The results of batch studies revealed that chromium was always preferentially adsorbed regardless of the peat type tested. The results of these studies further confirm that remediation of metal-contaminated waters using peats will require selection of specific peats to match the contaminants.« less

Peat deposits of North Carolina: Bulletin 88

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ingram, R.L.

1987-01-01

Fuel-grade peat is an accumulation of partially decomposed plant material that has less than 25% non-combustible material (ash). In eastern North Carolina peat has formed in the past 10,000 years in swamps or pocosins (coastal swamps), Carolina bays, and river floodplains. Most of the peat is found at the surface with no over-burden and usually ranges in thickness from 1 to 15 ft with an average of 4-1/2 ft. The mean ash content of the fuel-grade peats is about 7.4%, but ash contents of less than 5% are common in most peat deposits. Heating values average 10,100 Btu/lb on amore » moisture-free basis. Fuel-grade peat deposits cover about 677,000 acres (1060 sq mi) in coastal North Carolina with total resources of about 500 million tons of moisture-free peat. Of this total, about 284,000 acres (444 sq mi) with 319 million tons are underlain by peat greater than 4 ft thick. Peat resources are concentrated in the pocosins or coastal swamps of northeastern North Carolina with the Albemarle-Pamlico peninsula having 55% of the resources and the Dismal Swamp, 11%. The remaining coastal swamp deposits are small but significant. Although 96 Carolina bays have peat, only 46 have peat greater than 4 ft thick; and only one has more than 1 million tons of peat. None of the river floodplain peats located were very large, continuous, or of high quality. 75 refs.« less

Polycyclic aromatic hydrocarbons in post-fire soils of drained peatlands in western Meshchera (Moscow region, Russia)

NASA Astrophysics Data System (ADS)

Tsibart, A.; Gennadiev, A.; Koshovskii, T.; Watts, A.

2014-12-01

Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants that arrive in the environment from numerous anthropogenic and natural sources, but the data on their natural sources including wildfires remain insufficient. The level of contamination and the composition of PAHs in soils of the areas affected by wildfires were studied in this work. The study was conducted in the Moscow region (Russia) in areas occupied by drained peatland and strongly damaged by fires in 2002, 2010 and 2012. The features of PAH accumulation and the profile distributions in histosols and histic podzols after the fires of different times were analyzed. It was shown that new soil horizons formed after the fires - Cpir, Hpir and incipient O horizons - and that these horizons differ in PAH accumulation rate. Maximal total concentrations of 14 PAHs were detected in charred peat horizons Hpir (up to 330 ng g-1) and in post-fire incipient O horizons (up to 180 ng g-1), but the high-molecular-weight PAHs (benz(ghi)perylene, benz(a)pyrene, benz(k)fluoranthene) were revealed only in charry peat horizons. The trends of higher PAH concentrations were found in cases when smoldering combustion resulted in rather thick residual peat horizons. In cases of almost complete pyrogenic destruction of He horizons, total PAH concentrations were no more than 50 ng g-1. Also, PAH accumulation in upper horizons of soils near the sites of the latest fires was observed.

Polycyclic aromatic hydrocarbons in post-pyrogenic soils of drained peatlands in West Meshchera (Moscow Region, Russia)

NASA Astrophysics Data System (ADS)

Tsibart, A. S.; Gennadiev, A. N.; Koshovskii, T. S.

2014-05-01

Polycyclic aromatic hydrocarbons (PAHs) are priority pollutants and they arrive to the environment from numerous anthropogenic and natural sources, but the data on their natural sources which include wildfires remains insufficient. The level of contamination and the composition of PAHs in soils of the areas affected by wildfires were studied in this work. The study was conducted in Moscow Region (Russia) on the territories occupied with drained peatland and strongly damaged by fires of 2002, 2010 and 2012. The features of PAHs accumulation and profile distribution in histosols and histic podzols after the fires of different time were analyzed. It was shown that new soil horizon form after the fires - Cpir, Hpir and incipient O horizons, and these horizons differ in PAHs accumulation rate. Maximal total concentrations of 14 PAHs were detected in charry peat horizons Hpir (up to 330 ng g-1) and in post-pyrogenic incipient O horizons (up to 180 ng g-1), but the high-molecular weight PAHs (benz(ghi)perylene, benz(a)pyrene, benz(k)fluoranthene) were revealed only in charry peat horizons. The trends to higher PAHs concentrations were found in cases of incomplete burning out of peat horizons while in cases of almost complete pyrogenic destruction of He horizons total PAHs concentration were no more than 50 ng g-1. Also the PAHs accumulation in upper horizons of soils near the sites of latest fires was observed.

Modeling Peat Ages Using 7Be Data to Account for Downwash of 210Pb

NASA Astrophysics Data System (ADS)

Manies, K.; Fuller, C.; Jones, M.

2016-12-01

In order to determine the amount of peat, and thus carbon, which has accumulated since the last thaw event, we are interested in dating the surface layers of boreal thermokarst bogs. However, there can often be a mismatch by several decades between dates obtained using 210Pb, 14C, or 137Cs. We found that 210Pb-based dates were almost always younger than 14C-based dates. One of the limitations often cited regarding the use of 210Pb dating for peatlands is the potential for this radionuclide to be transported down the soil profile, biasing the mean accumulation rate (MAR) towards higher values which, in turn, results in younger ages at a specific horizon. 7Be, which has similar depositional behaviors as 210Pb but a much shorter half-life (53.22 days), can be used to help determine if there is movement of 210Pb through surface layers and the depths to which 210Pb-bearing particles are transported (over the mean life of 7Be). These data can then be used in new models, such as the Linked Radionuclide aCcumulation model (LRC; Landis et al., 2016, http://dx.doi.org/10.1016/ j.gca.2016.02.2013), which account for 210Pb downwash when calculating soil horizon ages. To this end, we measured 7Be within a bog four times over the growing season. 7Be was found to 4 cm in May, reached its maximum depth of penetration in July (7 cm), and then receded again to 4 cm. The maximum integrated 7Be activity was also found in July. This pattern is similar to other studies which found 7Be deposition decreased over the rainy season. Next, we will calculate peat ages with models that include downwash of 210Pb, the depths of which will be based on the penetration depth of 7Be. These ages will be compared to 210Pb ages obtained with both the Constant Rate of Supply (CRS) and Constant Flux - Constant Sedimentation (CF:CS) models and to 137Cs- and 14C-derived ages. We anticipate that dates based on models that include some transport of 210Pb into the soil profile will provide more accurate peat formation dates and allow for more accurate carbon accumulation rates.

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raivonen, Maarit; Smolander, Sampo; Backman, Leif

Wetlands are one of the most significant natural sources of methane (CH 4) to the atmosphere. They emit CH 4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH 4, in addition to carbon dioxide (CO 2). Production of CH 4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH 4 emissions are thus needed for upscaling observations to estimate present CH 4 emissions and for producing scenarios of future atmospheric CH 4 concentrations. Aiming at a CH 4 model that can bemore » added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH 4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH 4, CO 2, and oxygen (O 2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH 4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH 4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH 4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH 4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O 2 concentrations that affect the CH 4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH 4 emissions in this model version.« less

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

NASA Astrophysics Data System (ADS)

Raivonen, Maarit; Smolander, Sampo; Backman, Leif; Susiluoto, Jouni; Aalto, Tuula; Markkanen, Tiina; Mäkelä, Jarmo; Rinne, Janne; Peltola, Olli; Aurela, Mika; Lohila, Annalea; Tomasic, Marin; Li, Xuefei; Larmola, Tuula; Juutinen, Sari; Tuittila, Eeva-Stiina; Heimann, Martin; Sevanto, Sanna; Kleinen, Thomas; Brovkin, Victor; Vesala, Timo

2017-12-01

Wetlands are one of the most significant natural sources of methane (CH4) to the atmosphere. They emit CH4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH4, in addition to carbon dioxide (CO2). Production of CH4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH4 emissions are thus needed for upscaling observations to estimate present CH4 emissions and for producing scenarios of future atmospheric CH4 concentrations. Aiming at a CH4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH4, CO2, and oxygen (O2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O2 concentrations that affect the CH4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH4 emissions in this model version.

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

DOE PAGES

Raivonen, Maarit; Smolander, Sampo; Backman, Leif; ...

2017-12-22

Wetlands are one of the most significant natural sources of methane (CH 4) to the atmosphere. They emit CH 4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH 4, in addition to carbon dioxide (CO 2). Production of CH 4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH 4 emissions are thus needed for upscaling observations to estimate present CH 4 emissions and for producing scenarios of future atmospheric CH 4 concentrations. Aiming at a CH 4 model that can bemore » added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH 4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH 4, CO 2, and oxygen (O 2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH 4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH 4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH 4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH 4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O 2 concentrations that affect the CH 4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH 4 emissions in this model version.« less

A Mediterranean free-floating peat mire hosts microbial communities shared by cold latitude habitats

NASA Astrophysics Data System (ADS)

Concheri, Giuseppe; Stevanato, Piergiorgio; Zaccone, Claudio; Shotyk, William; D'Orazio, Valeria; Miano, Teodoro; Lobianco, Daniela; Piffanelli, Pietro; Rizzi, Valeria; Ferrandi, Chiara; Squartini, Andrea

2017-04-01

The microbiological features of a peculiar and hitherto unexplored environment, i.e., a 4m-deep, free-floating peat island located within the Posta Fibreno lake (central Italy), were analyzed via DNA-based techniques. Methods included RealTime PCR targeting for nitrogen (N) cycle genes (nitrification from eubacteria and archaea, denitrification, N fixation), and Next Generation Sequencing (NGS) using an Illumina platform of prokaryotic (16S) and eukaryotic (ITS) amplicons to assess community members identity and abundance. Two depths were sampled at ca. 40 and 280 cm from the surface, the former corresponding to a portion of Sphagnum residues accumulated less than 30 yrs ago above the water level, and the latter mainly consisting of silty peat belonging to the deeply submerged part of the island, dating back to 1520-1660 AD. Bacterial gene abundances for the N cycle were consistently higher in the deeper sample. Sequencing analyses allowed identifying for the surface sample 1738 prokaryotic and 310 eukaryotic Operational Taxonomic Units (OTUs), while, for the deeper sample, the corresponding values were 2026 and 291 respectively. There was a very limited taxa overlap between the two layers' communities in which dominant taxa featured two different sulphate-reducing Deltaproteobacteria for prokaryotes. For eukaryotes, the surface sample was dominated by the Neobulgaria (Ascomycota) genus, while in the deeper one three quarters of the ITS reads were featured by a taxon observed in Antarctic lakes. The functional guilds represented pertain mostly to species involved in slow organic matter degradation and contexts in which dissolved organic carbon contains one-atom compounds, supportive of methylotrophy and methanogenesis. The identity of taxa partitioning between the acidic surface layer and the neutral core is very reminiscent of the differences reported between bogs and fens peatland types respectively, supporting the view of Posta Fibreno as a hybrid between the two main models. A remarkable feature is the coincidence of most taxa observed with database subjects isolated from mires and lakes in boreal/polar environments in spite of the fact that Posta Fibreno is located in sub-Mediterranean climate conditions. This instance suggests a common ecological feature linking peat-forming mires and habitats alike, in which the process factor would rule in determining the biotic composition in spite of the macroclimatic and geographical variables. The principle offers interpretive clues for a deeper understanding of a number of other biotic-environmental interplay contexts.

High Diversity of Planctomycetes in Soils of Two Lichen-Dominated Sub-Arctic Ecosystems of Northwestern Siberia

PubMed Central

Ivanova, Anastasia A.; Kulichevskaya, Irina S.; Merkel, Alexander Y.; Toshchakov, Stepan V.; Dedysh, Svetlana N.

2016-01-01

A wide variety of terrestrial ecosystems in tundra have a ground vegetation cover composed of reindeer lichens (genera Cladonia and Cetraria). The microbial communities of two lichen-dominated ecosystems typical of the sub-arctic zone of northwestern Siberia, that is a forested tundra soil and a shallow acidic peatland, were examined in our study. As revealed by molecular analyses, soil and peat layers just beneath the lichen cover were abundantly colonized by bacteria from the phylum Planctomycetes. Highest abundance of planctomycetes detected by fluorescence in situ hybridization was in the range 2.2–2.7 × 107 cells per gram of wet weight. 16S rRNA gene fragments from the Planctomycetes comprised 8–13% of total 16S rRNA gene reads retrieved using Illumina pair-end sequencing from the soil and peat samples. Lichen-associated assemblages of planctomycetes displayed unexpectedly high diversity, with a total of 89,662 reads representing 1723 operational taxonomic units determined at 97% sequence identity. The soil of forested tundra was dominated by uncultivated members of the family Planctomycetaceae (53–71% of total Planctomycetes-like reads), while sequences affiliated with the Phycisphaera-related group WD2101 (recently assigned to the order Tepidisphaerales) were most abundant in peat (28–51% of total reads). Representatives of the Isosphaera–Singulisphaera group (14–28% of total reads) and the lineages defined by the genera Gemmata (1–4%) and Planctopirus–Rubinisphaera (1–3%) were present in both habitats. Two strains of Singulisphaera-like bacteria were isolated from studied soil and peat samples. These planctomycetes displayed good tolerance of low temperatures (4–15°C) and were capable of growth on a number of polysaccharides, including lichenan, a characteristic component of lichen-derived phytomass. PMID:28066382

Behavior of lead in pristine and urbanized acid wetlands in the New Jersey pinelands with special reference to the role of Sphagnum moss

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vedagiri, U.K.

1989-01-01

The purpose of this study was to investigate the behavior of lead in naturally acidic Sphagnum moss-dominated wetlands of the New Jersey Pinelands and to compare it to the behavior of lead in similar wetlands which had been impacted by storm-water runoff. Data from the field showed that the runoff-impacted sites were characterized by elevated pH, elimination of Spaghnum ground cover, erosion of peat substrate and high lead accumulations, contributing to an effective but decreasing sink capacity. Laboratory experiments explored differences in fractionation, mobility and bioavailability of lead between the two systems. The low pH and high dissolved organic mattermore » of the pristine waters led to higher solubilization and complexing of added lead compared to impacted waters. Lead added to runoff showed unexpectedly high solubility and lability, possibly due to low suspended solids. Lead added to runoff was also much more mobile vertically through peat columns than lead added to swampwater, possibly due to its high lability. The extremely high porosity of the peat substrate allows rapid vertical migration of solutes during events of sudden influx, such as storms. Sphagnum moss greatly decreased vertical transport by binding and flow retardation. The lead that is held in the moss layer was differentially available to different species. Red maple seedlings were better able to take up lead from the peat substrate in the absence of moss cover while cranberry plants showed the reverse pattern. This may be related to differences in rooting requirements and growth of the two species. Lead added in runoff was initially less available to the plants than in swampwater, but was ultimately taken up the red maple, which could tolerate conditions in the impacted substrates.« less

Could managed burning of peatlands lead to carbon storage?

NASA Astrophysics Data System (ADS)

Clay, G.; Worrall, F.

2007-12-01

Peatlands are the UK's largest single terrestrial carbon store with carbon stored in UK peatlands than in forests of Britain and France combined. Unlike most northern peatlands in the peat soils of the UK are heavily managed for recreation and agriculture and due to their proximity to major centres of population are under more anthropogenic pressure than most peatlands. A typical management strategy on UK upland peats is the use of managed fire to restrict vegetation. Fires are used upon a 10-25 year rotation and are described as "cool" as they remove the crown of the vegetation without scorching the litter layer or the underlying soil. In this case the fire destroys primary productivity and limits litter production but produces char. Char is a low volume, highly refractory, high carbon content product while litter is a high volume, decomposable, lower carbon content product. Therefore, the question is if there are fire conditions underwhich the production of char causes more carbon to be stored in the peat than would have been stored if no fire management had been employed. This study uses detailed vegetation studies from a long term monitoring site in order to assess litter and biomass production; in laboratory experimental burns were undertaken in order to assess the amount and controls upon char production and the carbon content of that char. Results of field and laboratory observations are used to model carbon accumulation under s aseries of fire management scenarios and the modelling shows that cools burns at long rotations could lead to higher carbon storage than if no fire had occurred, further than in several cases more carbon accumulation occurred even if less depth of peat was generated.

Could managed burning of peatlands lead to enhanced carbon storage?

NASA Astrophysics Data System (ADS)

Worrall, F.; Clay, G. D.

2009-04-01

Peatlands are the UK's largest single terrestrial carbon store with carbon stored in UK peatlands than in forests of Britain and France combined. Unlike most northern peatlands in the peat soils of the UK are heavily managed for recreation and agriculture and due to their proximity to major centres of population are under more anthropogenic pressure than most peatlands. A typical management strategy on UK upland peats is the use of managed fire to restrict vegetation. Fires are used upon a 10-25 year rotation and are described as "cool" as they are designed to remove the crown of the vegetation without scorching the litter layer or the underlying soil. In this case the fire destroys primary productivity and limits litter production but produces char. Char is a low volume, highly refractory, high carbon content product while litter is a high volume, decomposable, lower carbon content product. Therefore, the question is if there are fire conditions under which the production of char causes more carbon to be stored in the peat than would have been stored if no fire management had been employed. This study combines field studies of recent managed burns and wildfires along with detailed vegetation studies from a long term monitoring site in order to assess litter, biomass and black carbon production. In the laboratory experimental burns were undertaken in order to assess the amount and controls upon char production and the carbon content of that char. Results of field and laboratory observations are used to model carbon accumulation under a series of fire management scenarios and the modelling shows that cools burns at long rotations could lead to higher carbon storage than if no fire had occurred, further in several cases more carbon accumulation occurred even if less depth of peat was generated.

Holocene sedimentation at Corkscrew Swamp (Collier Co. ): A model for the origin and evolution of the present wetland-dominated regime of south Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, P.A.; Duever, M.J.; Meeder, J.F.

1993-03-01

A two-layer peat-over-marl (calcitic mud) sequence characterizes Corkscrew Swamp, a swamp/marsh complex in northern Big Cypress Swamp. The marl began depositing about 10,600 BP and based upon the regional modern analog represents a marsh (grassy) environment of relatively short seasonal flooding, rather than a marl lake. The marsh succeeded formerly dry land of full-glacial times on a long-emerged marine-sand and limestone peninsula. About 5,700 BP peat deposition began by the development of longer-flooded wetland, either marsh or woody swamp vegetation. Both shifts (Pleistocene/Holocene and mid-Holocene) represent onsets of wetter conditions, either episodically or by slowly passing critical thresholds, under controlmore » of climate and sea level (hydrologic baselevel). With the rise in average water level at and following each shift, in part by feedback from sediment infilling of the shallow (ca. 2.5m) mineral-substrate basin, the wetland and its deposit expanded upslope, both vertically and outward. A younger basal-peat date (3,900 BP) occurs toward the periphery. Some local topographic alteration by peat fire about 500 BP persists and affects the modern swamp vegetation. A wide swamp-to-marsh shift in other parts may have a similar cause. The shorter record yet revealed for the northern Everglades shows the same two-stage sequence, similar timing in peatland development, wetland and sediment expansion, and long-term (but there different) influences of local peatland topographic alteration. Many wetland areas in South Florida data from a mid-Holocene shift (7,000--4,000 BP).« less

Peat Soil Stabilization using Lime and Cement

NASA Astrophysics Data System (ADS)

Zambri, Nadhirah Mohd; Ghazaly, Zuhayr Md.

2018-03-01

This paper presents a study of the comparison between two additive Lime and Cement for treating peat soil in term of stabilization. Peat and organic soils are commonly known for their high compressibility, extremely soft, and low strength. The aim of this paper is to determine the drained shear strength of treated peat soil from Perlis for comparison purposes. Direct Shear Box Test was conducted to obtain the shear strength for all the disturbed peat soil samples. The quick lime and cement was mixed with peat soil in proportions of 10% and 20% of the dry weight peat soil. The experiment results showed that the addition of additives had improved the strength characteristics of peat soil by 14% increment in shear strength. In addition, the mixture of lime with peat soil yield higher result in shear strength compared to cement by 14.07% and 13.5% respectively. These findings indicate that the lime and cement is a good stabilizer for peat soil, which often experienced high amount of moisture content.

Geophysical survey for groundwater potential investigation in peat land area, Riau, Indonesia

NASA Astrophysics Data System (ADS)

Islami, N.; Irianti, M.; Azhar; Nor, M.; Fakhrudin

2018-04-01

Tropical forests, especially peat lands, are particularly vulnerable to forest fires. Fires are the most common disasters in peat lands in the dry season, especially in Riau Province, Indonesia. In the process of extinguishing the peat fire, several substantial problems arise to stop peat fires during this period. This study aims to determine the possibility of using ground water as a source of water to anticipate the early mitigation of peat land fires disaster. The geoelectrical resistivity surveys were used to predict the subsurface geological data including peat thickness and depth of aquifers. The geometry of peat lands was determined using geostatistics based on geoelectrical resistivity interpretation data. Peat Land thickness varies up to 4 m in the north and is thinner to the south. A shallower and deeper aquifer is available at a depth of 13 m to 18 m and 70 m to 90 m respectively. In general, the potential of groundwater in the shallow aquifer is predicted to be sufficient for peat land watering anytime.

46 CFR 148.290 - Peat moss.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Peat moss. 148.290 Section 148.290 Shipping COAST GUARD... SPECIAL HANDLING Special Requirements for Certain Materials § 148.290 Peat moss. (a) Before shipment, peat... handling or coming into contact with peat moss must wear gloves, a dust mask, and goggles. ...

Fire severity is more sensitive to low fuel moisture content on Calluna heathlands than on peat bogs.

PubMed

Grau-Andrés, Roger; Davies, G Matt; Gray, Alan; Scott, E Marian; Waldron, Susan

2018-03-01

Moorland habitats dominated by the dwarf shrub Calluna vulgaris provide important ecosystem services. Drought is projected to intensify throughout their range, potentially leading to increased fire severity as moisture is a key control on severity. We studied the effect of low fuel moisture content (FMC) on fire severity by using 2×2m rain-out shelters prior to completing 19 experimental fires in two sites in Scotland (UK): a dry heath with thin organic soils and a raised bog with deep, saturated peat, both dominated by Calluna vulgaris. Reduced FMC of the moss and litter (M/L) layer at both sites, and the soil moisture of the dry heath, increased fire-induced consumption of the M/L layer and soil heating at both sites. Increase in fire severity was greater at the dry heath than at the raised bog, e.g. average maximum temperatures at the soil surface increased from 31°C to 189°C at the dry heath, but only from 10°C to 15°C at the raised bog. Substantial M/L layer consumption was observed when its FMC was below 150%. This led to larger seasonal and daily soil temperature fluctuation, particularly at the dry heath during warm months. The results suggest that low FMC following predicted changes in climate are likely to increase wildfire severity and that the impact on vegetation composition and carbon stores may be greater at heathlands than at peatlands. Managed burning aiming to minimise fire severity (e.g. ignition of the M/L layer and exposure to lethal temperatures of ericoid seeds) should be carried out when the FMC of the M/L layer is above 150% and the FMC of the soil is above 200-300%. Copyright © 2017 Elsevier B.V. All rights reserved.

Global latitudinal trends in peat recalcitrance quantified with calibrated FTIR spectroscopy

NASA Astrophysics Data System (ADS)

Hodgkins, S. B.; Richardson, C. J.; Dommain, R.; Wang, H.; Glaser, P. H.; Verbeke, B. A.; Rogers, K.; Winkler, B. R.; Missilmani, M.; Flanagan, N. E.; Ho, M.; Hoyt, A.; Harvey, C. F.; Cobb, A.; Rich, V. I.; Vining, S. R.; Hough, M.; Saleska, S. R.; Podgorski, D. C.; Tfaily, M. M.; Wilson, R.; Holmes, B.; de La Cruz, F.; Toufaily, J.; Hamdan, R.; Cooper, W. T.; Chanton, J.

2017-12-01

Peatlands are a major global carbon reservoir (528-600 Pg). Most peat is found at high latitudes, where organic matter decomposition is slowed by cold temperatures and water-saturated conditions. Nonetheless, a significant portion of global peatland carbon (10-30%) is in tropical peatlands. The factors that allow peat accumulation in warm climates remain uncertain, raising the question of whether these factors may preserve peat in boreal regions as they warm. In this study, we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Carbohydrate and aromatic contents were estimated based on a newly-developed analysis method for Fourier transform infrared (FTIR) spectra. In this method, peaks are baseline-corrected and normalized to the integrated spectral area using an automated R script, then calibrated to known concentrations using standards. This technique showed trends that were in agreement with those seen with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and 13C-NMR spectroscopy. Along the latitudinal transect, we found that near-surface (sub)tropical peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, leading to recalcitrance that allows (sub)tropical peat to persist despite warm temperatures. The chemistry of (sub)tropical peat reflects a combination of recalcitrant plant inputs, and more extensive humification driven by higher temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat deposits, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable in the face of temperature increases up to 9 °C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats.

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

NASA Astrophysics Data System (ADS)

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

2012-03-01

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

Deformation behaviors of peat with influence of organic matter.

PubMed

Yang, Min; Liu, Kan

2016-01-01

Peat is a kind of special material rich in organic matter. Because of the high content of organic matter, it shows different deformation behaviors from conventional geotechnical materials. Peat grain has a non-negligible compressibility due to the presence of organic matter. Biogas can generate from peat and can be trapped in form of gas bubbles. Considering the natural properties of peat, a special three-phase composition of peat is described which indicates the existence of organic matter and gas bubbles in peat. A stress-strain-time model is proposed for the compression of organic matter, and the surface tension effect is considered in the compression model of gas bubbles. Finally, a mathematical model has been developed to simulate the deformation behavior of peat considering the compressibility of organic matter and entrapped gas bubbles. The deformation process is the coupling of volume variation of organic matter, gas bubbles and water drainage. The proposed model is used to simulate a series of peat laboratory oedometer tests, and the model can well capture the test results with reasonable model parameters. Effects of model parameters on deformation of peat are also analyzed.

The peats of Costa Rica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obando A, L.; Malavassi R, L.; Ramirez E, O.

The objectives of this investigation were: (1) to locate potential peat deposits in Costa Rica; (2) to estimate as closely as possible by representative sampling the amount of peat present in each deposit, and (3) to make a preliminary evaluation of the quality of the peat in each deposit. With information from soil maps and a 3-week survey of Costa Rica, it is estimated that a potential area of about 1000 km{sup 2} is covered by peat. Most of the peat area (about 830 km{sup 2}) is in northeastern Costa Rica in the Tortuguero area. An aerial survey identified themore » potential peat areas by the exclusive presence of the Yolillo palm. The next largest potential area of peat (about 175 km{sup 2}) is in the cloud-covered areas of the Talamanca Mountains. Some reconnaissance has been done in the Talamanca Mountains, and samples of the peat indicate that it is very similar to the sphagnum peat moss found in Canada and the northern US. Smaller bogs have been discovered at Medio Queso, El Cairo, Moin, and the Limon airport. Two bogs of immediate interest are Medio Queso and El Cairo. The Medio Queso bog has been extensively sampled and contains about 182,000 metric tons (dry) of highly decomposed peat, which is being used as a carrier for nitrogen-fixing bacteria. The El Cairo bog is sparsely sampled and contains about 1,300,000 metric tons of slightly decomposed dry peat. Plans are to use this peat in horticultural applications on nearby farms. 10 refs., 11 figs., 7 tabs.« less

SPRUCE Whole Ecosystem Warming (WEW) Peat Water Content and Temperature Profiles for Experimental Plot Cores Beginning June 2016

DOE Data Explorer

Gutknecht, J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Kluber, L. A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hanson, P. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Schadt, C. W. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2016-06-01

This data set provides the peat water content and peat temperature at time of sampling for peat cores collected before and during the SPRUCE Whole Ecosystem Warming (WEW) study. Cores for the current data set were collected during the following bulk peat sampling events: 13 June 2016 and 23 August 2016. Over time, this dataset will be updated with each new major bulk peat sampling event, and dates/methods will be updated accordingly.

Distribution and mobility of lead (Pb), copper (Cu), zinc (Zn), and antimony (Sb) from ammunition residues on shooting ranges for small arms located on mires.

PubMed

Mariussen, Espen; Johnsen, Ida Vaa; Strømseng, Arnljot Einride

2017-04-01

An environmental survey was performed on shooting ranges for small arms located on minerotrophic mires. The highest mean concentrations of Pb (13 g/kg), Cu (5.2 g/kg), Zn (1.1 g/kg), and Sb (0.83 g/kg) in the top soil were from a range located on a poor minerotrophic and acidic mire. This range had also the highest concentrations of Pb, Cu, Zn, and Sb in discharge water (0.18 mg/L Pb, 0.42 mg/L Cu, 0.63 mg/L Zn, and 65 μg/L Sb) and subsurface soil water (2.5 mg/L Pb, 0.9 mg/L Cu, 1.6 mg/L Zn, and 0.15 mg/L Sb). No clear differences in the discharge of ammunition residues between the mires were observed based on the characteristics of the mires. In surface water with high pH (pH ~7), there was a trend with high concentrations of Sb and lower relative concentrations of Cu and Pb. The relatively low concentrations of ammunition residues both in the soil and soil water, 20 cm below the top soil, indicates limited vertical migration in the soil. Channels in the mires, made by plant roots or soil layer of less decomposed materials, may increase the rate of transport of contaminated surface water into deeper soil layers and ground water. A large portion of both Cu and Sb were associated to the oxidizable components in the peat, which may imply that these elements form inner-sphere complexes with organic matter. The largest portion of Pb and Zn were associated with the exchangeable and pH-sensitive components in the peat, which may imply that these elements form outer-sphere complexes with the peat.

A Stratigraphic Pollen Record from a Late Pleistocene Cypress Forest, Northern Gulf of Mexico Continental Shelf

NASA Astrophysics Data System (ADS)

Reese, A.; Harley, G. L.; DeLong, K. L.; Bentley, S. J.; Xu, K.; Gonzalez Rodriguez, S. M.; Truong, J. T.; Obelcz, J.; Caporaso, A.

2017-12-01

Stratigraphic pollen analysis was performed on a layer of preserved peat found near the bottom of a 4.75m vibracore taken in 18m of water off the coast of Orange Beach, Alabama. The core was taken from a site where the remains of a previously buried bald cypress (Taxodium distichum) forest was discovered after wave action, likely from Hurricane Ivan in 2004, scoured and removed the overlying Holocene/late Pleistocene sand sheet. Many of the cypress stumps found at the site are still in growth position, and rooted in the preserved terrestrial soils below. Radiocarbon dating of the peat recovered in core DF1 suggests that the sediment is likely Marine Isotope Stage 3 (MIS 3), or earlier. We hypothesize that the site was quickly buried and preserved by floodplain aggradation associated with sea-level rise that occurred near the end of MIS 3. This rare find provides an opportunity to study in situ fossil pollen from a glacial refugium in the Northern Gulf of Mexico. Pollen results from the lowermost sections within the peat layer show an assemblage consistent with a bald cypress/tupelo gum (Nyssa aquatica) backwater. This is eventually replaced by a more open, possibly brackish, environment, dominated by grasses (Poaceae) and sedges (Cyperaceae). During this change however, there is a brief but very interesting period where the pollen assemblage is likely analogous to the modern day Atlantic Coastal Plain Blackwater Levee/Bar Forests of North and South Carolina. In this modern assemblage, as well as the core samples, birch (Betula), oak (Quercus) and bald cypress are the dominant taxa, along with a strong presence of alder (Alnus), grasses and sedges. We hypothesize that these bar forests formed on areas of higher ground, which resulted from floodplain aggradation that accompanied sea level rise at the end of MIS 3.

Recreating a functioning forest soil in reclaimed oil sands in northern alberta: an approach for measuring success in ecological restoration.

PubMed

Rowland, S M; Prescott, C E; Grayston, S J; Quideau, S A; Bradfield, G E

2009-01-01

During oil-sands mining all vegetation, soil, overburden, and oil sand is removed, leaving pits several kilometers wide and up to 100 m deep. These pits are reclaimed through a variety of treatments using subsoil or a mixed peat-mineral soil cap. Using nonmetric multidimensional scaling and cluster analysis of measurements of ecosystem function, reclamation treatments of several age classes were compared with a range of natural forest ecotypes to discover which treatments had created ecosystems similar to natural forest ecotypes and at what age this occurred. Ecosystem function was estimated from bioavailable nutrients, plant community composition, litter decomposition rate, and development of a surface organic layer. On the reclamation treatments, availability of nitrate, calcium, magnesium, and sulfur were generally higher than in the natural forest ecotypes, while ammonium, P, K, and Mn were generally lower. Reclamation treatments tended to have more bare ground, grasses, and forbs but less moss, lichen, shrubs, trees, or woody debris than natural forests. Rates of litter decomposition were lower on all reclamation treatments. Development of an organic layer appeared to be facilitated by the presence of shrubs. With repeated applications of fertilizers, measured variables for the peat-mineral amendments fell within the range of natural variability at about 20 yr. An intermediate subsoil layer reduced the need for fertilizer and conditions resembling natural forests were reached about 15 yr after a single fertilizer application. Treatments over tailings sand receiving only one application of fertilizer appeared to be on a different trajectory to a novel ecosystem.

SPRUCE S1 Bog Plant-Available Nutrients Assessed with Ion-Exchange Resins from 2011-2012 in the Southern End of the S1 Bog

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iversen, C. M.; Ontl, T. A.; Brice, D. J.

This data set consists of observations of plant-available nutrients assessed using ion-exchange resin capsules incubated serially in aerobic and anaerobic peat layers beginning in 2011. Data were collected from 2011 to 2012 (prior to the construction of the SPRUCE experimental plots) at the southern end of the S1 Bog at three depths in hollow microtopography only.

The Characteristics of Peats and Co2 Emission Due to Fire in Industrial Plant Forests

NASA Astrophysics Data System (ADS)

Ratnaningsih, Ambar Tri; Rayahu Prasytaningsih, Sri

2017-12-01

Riau Province has a high threat to forest fire in peat soils, especially in industrial forest areas. The impact of fires will produce carbon (CO2) emissions in the atmosphere. The magnitude of carbon losses from the burning of peatlands can be estimated by knowing the characteristics of the fire peat and estimating CO2 emissions produced. The objectives of the study are to find out the characteristics of fire-burning peat, and to estimate carbon storage and CO2 emissions. The location of the research is in the area of industrial forest plantations located in Bengkalis Regency, Riau Province. The method used to measure peat carbon is the method of lost in ignation. The results showed that the research location has a peat depth of 600-800 cm which is considered very deep. The Peat fiber content ranges from 38 to 75, classified as hemic peat. The average bulk density was 0.253 gram cm-3 (0.087-0,896 gram cm-3). The soil ash content is 2.24% and the stored peat carbon stock with 8 meter peat thickness is 10723,69 ton ha-1. Forest fire was predicted to burn peat to a depth of 100 cm and produced CO2 emissions of 6,355,809 tons ha-1.

Reduction of trichloroethylene and nitrate by zero-valent iron with peat.

PubMed

Min, Jee-Eun; Kim, Meejeong; Pardue, John H; Park, Jae-Woo

2008-02-01

The feasibility of using zero-valent iron (ZVI) and peat mixture as in situ barriers for contaminated sediments and groundwater was investigated. Trichloroethylene (TCE) and nitrate (NO(3)(-)), redox sensitive contaminants were reduced by ZVI and peat soil mixture under anaerobic condition. Peat was used to support the sorption of TCE, microbial activity for biodegradation of TCE and denitrification while TCE and nitrate were reduced by ZVI. Decreases in TCE concentrations were mainly due to ZVI, while peat supported denitrifying microbes and further affected the sorption of TCE. Due to the competition of electrons, nitrate reduction was inhibited by TCE, while TCE reduction was not affected by nitrate. From the results of peat and sterilized peat, it can be concluded that peat was involved in both dechlorination and denitrification but biological reduction of TCE was negligible compared to that of nitrate. The results from hydrogen and methane gas analyses confirmed that hydrogen utilization by microbes and methanogenic process had occurred in the ZVI-peat system. Even though effect of the peat on TCE reduction were quantitatively small, ZVI and peat contributed to the removal of TCE and nitrate independently. The 16S rRNA analysis revealed that viable bacterial diversity was narrow and the most frequently observed genera were Bacillus and Staphylococcus spp.

Influences and interactions of inundation, peat, and snow on active layer thickness

DOE PAGES

Atchley, Adam L.; Coon, Ethan T.; Painter, Scott L.; ...

2016-05-18

Active layer thickness (ALT), the uppermost layer of soil that thaws on an annual basis, is a direct control on the amount of organic carbon potentially available for decomposition and release to the atmosphere as carbon-rich Arctic permafrost soils thaw in a warming climate. Here, we investigate how key site characteristics affect ALT using an integrated surface/subsurface permafrost thermal hydrology model. ALT is most sensitive to organic layer thickness followed by snow depth but is relatively insensitive to the amount of water on the landscape with other conditions held fixed. Furthermore, the weak ALT sensitivity to subsurface saturation suggests thatmore » changes in Arctic landscape hydrology may only have a minor effect on future ALT. But, surface inundation amplifies the sensitivities to the other parameters and under large snowpacks can trigger the formation of near-surface taliks.« less

Microbial Activity in Peat Soil Treated With Ordinary Portland Cement (OPC) and Coal Ashes

NASA Astrophysics Data System (ADS)

Rahman, J. A.; Mohamed, R. M. S. R.; Al-Gheethi, A. A.

2018-04-01

Peat soil is a cumulative of decayed plant fragment which developed as a result of microbial activity. The microbes degrade the organic matter in the peat soils by the production of hydrolysis enzyme. The least decomposed peat, known as fibric peat has big particles and retain lots of water. This made peat having high moisture content, up to 1500 %. The most decomposed peat known as sapric peat having fines particles and less void ratio. The present study aimed to understand the effects of solidification process on the bacterial growth and cellulase (CMCase) enzyme activity. Two types of mixing were designed for fibric, hemic and sapric peats; (i) Ordinary Portland cement (OPC) at an equal amount of dry peat, with 25 % of fly ash (FA) and total of coarse particle, a combination of bottom ash and fibre of 22 – 34 %, (ii) fibric peat was using water-to-binder ratio (w/b) = 1, 50% OPC, 25 % bottom ash (BA) and 25 % FA. For hemic and sapric peat, w/b=3 with 50 % OPC and 50 % BA were used. All samples were prepared triplicates, and were cured for 7, 14, 28 and 56 days in a closed container at room temperature. The results revealed that the first mix design giving a continuous strength development. However, the second mix design shows a decreased in strength pattern after day 28. The influence of the environment factors such as alkaline pH, reduction of the water content and peat temperature has no significant on the reduction amount of native microbes in the peat. The microbes survived in the solidified peat but the amount of microbes were found reduced for all types of mixing Fibric Mixed 1 (FM1), Hemic Mixed 1(HM1) and Sapric Mixed 1 (SM1) were having good strength increment for about 330 – 1427 % with enzymatic activity recorded even after D56. Nevertheless, with increase in the strength development through curing days, the enzymatic activities were reduced. For the time being, it can be concluded that the microbes have the ability to adapt with new environment. The reactivity of the microbes relates with the strength of solidified peat.

Factors affecting the mobilization of DOC and metals in a peat soil under a warmer scenario

NASA Astrophysics Data System (ADS)

Carrera, Noela; Barreal, María. Esther; Briones, María. Jesús I.

2010-05-01

Most climate change models predict an increase of temperature of 3-5°C in Southern Europe by the end of this century (IPCC 2007). However, changes in summer precipitations are more uncertain, and although a decrease in rainfall inputs is forecasted by most models, the magnitude of this effect has not been assessed properly (Rowell & Jones 2006). Peatland areas are very sensitive to climate change. In Galicia they survive in upland areas where cold temperatures and continuous moisture supply allow their presence. Besides abiotic factors, alterations in soil fauna activities can also affect peat turnover. Among them, enchytraeids are usually the most numerous invertebrate group in these systems and both temperature and moisture content regulate their abundances and vertical distribution. Previous studies have demonstrated that changes in their populations associated to increasing temperatures can significantly affect metal mobilization, namely iron and aluminium, together with an important decline in the acidity of the soil solution, which possibly eliminates one of the critical mechanisms restricting DOC release (Carrera et al., 2009). In this study we investigated whether changes in water content of the peat soil and soil invertebrate activities associated to increasing temperatures could alter the mobilization rates of Fe and Al and in turn, DOC. 72 undisturbed soil cores (6 cm diameter x 10 cm deep) with their associated vegetation were taken from a blanket bog in Galicia (NW Spain). Back at the laboratory they were sliced horizontally into two layers, (0-5cm and 5-10cm) which were defaunated by means of a wet extraction. Thereafter, the two soil layers derived from the same core were introduced in each microcosm by placing them in their original position but separated by a 1 mm nylon mesh to allow the vertical movements of the organisms. Half of the experimental units were adjusted to the used moisture values observed in the field (80% SWC, H1), whereas in the remaining half the moisture content was decreased to a lower value so that the activities of the soil organisms remained unaffected (60%, H2). Sixty enchytraeid individuals were inoculated into 18 units of each moisture treatment resulting in two animal treatments (+E and -E). Nine replicates of each treatment were incubated at 14°C and the rest were maintained at 19°C. Changes in enchytraeid populations during incubation were monitored by using a parallel series of 120 experimental units consisting of plastic containers which contained defaunated soil samples (two soil layers) separated by the nylon mesh and with the two moisture treatments as the microcosms (H1 and H2) following the same procedures as before. Next, the same number of enchytraeids was re-inoculated in half of these experimental units (+E and -E). The experiment run for 13 weeks; every 15 days, enchytraeid numbers, DOC, Fe and Al content in the leachates collected from each individual layer were determined. Results showed that both high temperature and moisture values promoted enchytraeid reproduction, with most individuals concentrated in the upper layer. This abundant enchytraeid population favoured the mobilization of DOC, Fe and Al to the soil solution. These findings suggest that modifications in soil faunal populations due to abiotic changes could enhance organic matter decomposition, contributing to the destabilization of these peatland systems. Increasing leaching of dissolved organic matter and metals could have negative implications, not only in terms of possible feed-backs to global warming but also as potential contaminants for aquatic ecosystems. References • Carrera N., Barreal M.E., Gallego P. & Briones M.J.I. (2009). Soil invertebrates control peatland C fluxes in response to warming. Functional Ecology 23: 637-648. • IPCC 2007. Climate change 2007. The Physical Science Basis. Solomon S., Qin D., Manning M., Chen Z., Marquis M., Averyt K.B., Tignor M. & Miller H.L. (Eds.). Cambridge University Press, Cambridge, UK. • Rowell D.P. & Jones R.G. (2006). Causes and uncertainty of future summer drying over Europe. Climate Dynamics 27: 281-299.

Comparison of Shear Strength Properties for Undisturbed and Reconstituted Parit Nipah Peat, Johor

NASA Astrophysics Data System (ADS)

Azhar, A. T. S.; Norhaliza, W.; Ismail, B.; Abdullah, M. E.; Zakaria, M. N.

2016-11-01

Shear strength of soil is required to determine the soil stability and design the foundations. Peat is known as a soil with complex natural formations which also contributes problems to the researchers, developers, engineers and contractors in constructions and infrastructures. Most researchers conducted experiment and investigation of shear strength on peat using shear box test and simple shear test, but only a few had discovered the behavior of peat using triaxial consolidated undrained test. The aim of this paper is to determine the undrained shear strength properties of reconstituted peat and undisturbed peat of Parit Nipah, Johor for comparison purposes. All the reconstituted peat samples were formed with the size that passed opening sieve 3.35 mm and preconsolidation pressure at 100 kPa. The result of undrained shear strength of reconstituted peat was 21kPa for cohesion with the angle of friction, 41° compare to the undisturbed peat with cohesion 10 kPa and angle of friction, 16°. The undrained shear strength properties result obtained shows that the reconstituted peat has higher strength than undisturbed peat. For relationship deviator stress-strain, σd max and excess pore pressure, Δu, it shows that both of undisturbed and reconstituted gradually increased when σ’ increased, but at the end of the test, the values are slightly dropped. The physical properties of undisturbed and reconstituted peat were also investigated to correlate with the undrained shear strength results.

Investigation of occupational radiation exposures to NORM at an Irish peat-fired power station and potential use of peat fly ash by the construction industry.

PubMed

Organo, C; Lee, E M; Menezes, G; Finch, E C

2005-12-01

Annually, approximately 15% of Ireland's electricity requirement is provided through the combustion of 3 x 10(6) tonnes of peat. While the literature on coal-fired power generation is quite abundant, studies on the peat-fired power generation industry from a radiological point of view are scarce. A study of the largest Irish peat-fired power plant was initiated to review the potential occupational radiation exposures arising from the occurrence of naturally occurring radioactive material (NORM) at different stages of the industrial process and to investigate any radiological health consequences that may arise should peat fly ash be used as a component of building materials. Ambient gamma dose rate measurements, radon measurements, quantification of the occupational exposure from inhalation of airborne particles (personal air sampling) and gamma spectrometry analysis of peat, peat ash and effluent samples from the ash ponds were undertaken. The results indicate that the radiation dose received by any worker involved in the processing of the peat and the handling of the ash resulting from peat combustion does not exceed 150 microSv per annum. Regulatory control of the peat-fired power generation is therefore unnecessary according to the Irish legislation with regards to NORM. The potential use of peat fly ash as a by-product in the building industry was also found to have a negligible radiological impact for construction workers and for members of the public.

Ceramic substrate including thin film multilayer surface conductor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolf, Joseph Ambrose; Peterson, Kenneth A.

2017-05-09

A ceramic substrate comprises a plurality of ceramic sheets, a plurality of inner conductive layers, a plurality of vias, and an upper conductive layer. The ceramic sheets are stacked one on top of another and include a top ceramic sheet. The inner conductive layers include electrically conductive material that forms electrically conductive features on an upper surface of each ceramic sheet excluding the top ceramic sheet. The vias are formed in each of the ceramic sheets with each via being filled with electrically conductive material. The upper conductive layer includes electrically conductive material that forms electrically conductive features on anmore » upper surface of the top ceramic sheet. The upper conductive layer is constructed from a stack of four sublayers. A first sublayer is formed from titanium. A second sublayer is formed from copper. A third sublayer is formed from platinum. A fourth sublayer is formed from gold.« less

Anthropogenic versus natural control on trace element and Sr-Nd-Pb isotope stratigraphy in peat sediments of southeast Florida (USA), ˜1500 AD to present

NASA Astrophysics Data System (ADS)

Kamenov, George D.; Brenner, Mark; Tucker, Jaimie L.

2009-06-01

Analysis of a well-dated peat core from Blue Cypress Marsh (BCM) provides a detailed record of natural and anthropogenic factors that controlled the geochemical cycles of a number of trace elements in Florida over the last five centuries. The trace elements were divided into "natural" and "anthropogenic" groups using concentration trends from the bottom to the top of the core. The "natural" group includes Li, Sc, Cr, Co, Ga, Ge, Zr, Nb, Cs, Ba, Hf, Y, Ta, Th, and REE (Rare Earth Elements). These elements show similar concentrations throughout the core, indicating that changes in human activities after European arrival in the "New World" did not affect their geochemical cycles. The "anthropogenic" group includes Pb, Cu, Zn, V, Sb, Sn, Bi, and Cd. Upcore enrichment of these elements indicates enhancement by anthropogenic activities. From the early 1500s to present, fluxes of the "anthropogenic" metals to the marsh increased significantly, with modern accumulation rates several-fold (e.g., V) to hundreds of times (e.g., Zn) greater than pre-colonial rates. The dominant input mechanism for trace elements from both groups to the marsh has been atmospheric deposition. Atmospheric input of a number of the elements, including the anthropogenic metals, was dominated by local sources during the last century. For several elements, long-distant transport may be important. For instance, REE and Nd isotopes provide evidence for long-range atmospheric transport dominated by Saharan dust. The greatest increase in flux of the "anthropogenic" metals occurred during the 20th century and was caused by changes in the chemical composition of atmospheric deposition entering the marsh. Increased atmospheric inputs were a consequence of several anthropogenic activities, including fossil fuel combustion (coal and oil), agricultural activities, and quarrying and mining operations. Pb and V exhibit similar trends, with peak accumulation rates in 1970. The principal anthropogenic source of V is oil combustion. The decline in V accumulation after 1970 in the BCM peat corresponds to the introduction of low-sulfur fuels and the change from heavy to distilled oils since the 1970s. After the 1920s, Pb distribution in the peat follows closely the history of alkyl lead consumption in the US, which peaked in the 1970s. Pb isotopes support this inference and furthermore, record changes in the ore sources used to produce leaded gasoline. Idaho ores dominated the peat Pb isotope record until the 1960s, followed by Pb from Mississippi Valley Type deposits from the 1960s to the 1980s. Enhanced fluxes of Cu, Zn, Cd, Sn, Sb, Bi, and to some extent Ni during the last century are likely also related to fossil fuel combustion. Local agricultural activities may also have influenced the geochemical cycles of Cu and Zn. The peat record shows enhanced U accumulation during the last century, possibly related to phosphate mining in western Florida. Sr isotopes in the peat core also reflect anthropogenic influence. The 87Sr/ 86Sr ratio decreases from natural background values in the basal part of the core to lower values in the upper part of the core. The Sr isotope shift is probably related to quarrying operations in Florida, and marks the first time an anthropogenic signal has been detected using the Sr isotope record in a peat core.

Removal of metal(oid)s from contaminated water using iron-coated peat sorbent.

PubMed

Kasiuliene, Alfreda; Carabante, Ivan; Bhattacharya, Prosun; Caporale, Antonio Giandonato; Adamo, Paola; Kumpiene, Jurate

2018-05-01

This study aimed at combining iron and peat to produce a sorbent suitable for a simultaneous removal of cations and anions from a solution. Peat powder, an industrial residue, was coated with iron by immersing peat into iron salt solutions. The adsorption efficiency of the newly produced sorbent towards As, Cr, Cu and Zn was tested by means of batch adsorption experiments at a constant pH value of 5. Coating of Fe on peat significantly increased the adsorption of As (from <5% to 80%) and Cr (from <3% to 25%) in comparison to uncoated peat. Removal of cations on coated peat slightly decreased (by 10-15%), yet remained within acceptable range. Electron Microscopy combined with X-Ray Energy Dispersive Spectroscopy revealed that iron coating on the peat was rather homogenous and As and Cr were abundantly adsorbed on the surface. By contrast, Cu and Zn displayed a sparing distribution on the surface of the iron coated peat. These results indicate that iron-peat simultaneously target sufficient amounts of both cations and anions and can be used for a one-step treatment of contaminated groundwater. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

USGS Publications Warehouse

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

1987-01-01

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

Substrate quality and nutrient availability influence CO2 production from tropical peat decomposition

NASA Astrophysics Data System (ADS)

Swails, E.; Jaye, D.; Verchot, L. V.; Hergoualc'h, K.; Wahyuni, N. S.; Borchard, N.; Lawrence, D.

2015-12-01

In Indonesia, peatlands are a major and growing source of greenhouse gas emissions due to increasing pressure from oil palm and pulp wood plantations. We are using a combination of field measures, laboratory experiments, and remote sensing to investigate relationships among land use, climatic factors and biogeochemical controls, and their influence on trace gas fluxes from tropical peat soils. Analysis of soils collected from peat sites on two major islands indicated substantial variation in peat substrate quality and nutrient content among land uses and geographic location. We conducted laboratory incubations to test the influence of substrate quality and nutrient availability on CO2 production from peat decomposition. Differences in peat characteristics attributable to land use change were tested by comparison of forest and oil palm peat samples collected from the same peat dome in Kalimantan. Regional differences in peat characteristics were tested by comparison of samples from Sumatra with samples from Kalimantan. We conducted additional experiments to test the influence of N and P availability and labile carbon on CO2 production. Under moisture conditions typical of oil palm plantations, CO2 production was higher from peat forest samples than from oil palm samples. CO2 production from Sumatra and Kalimantan oil palm samples was not different, despite apparent differences in nutrient content of these soils. N and P treatments representative of fertilizer application rates raised CO2 production from forest samples but not oil palm samples. Labile carbon treatments raised CO2 production in all samples. Our results suggest that decomposition of peat forest soils is nutrient limited, while substrate quality controls decomposition of oil palm soils post-conversion. Though fertilizer application could accelerate peat decomposition initially, fertilizer application may not influence long-term CO2 emissions from oil palm on peat.

A drowned lycopsid forest above the Mahoning coal (Conemaugh Group, Upper Pennsylvanian) in eastern Ohio, U.S.A

USGS Publications Warehouse

DiMichele, W.A.; Eble, C.F.; Chaney, D.S.

1996-01-01

Over 800 mud-filled casts of upright lycopsid tree stumps have been documented immediately above the Mahoning coal in an active underground mine located in northwestern Jefferson County, Ohio. The coal body originated as a pod-shaped peat body of ??? 60 km2. Trees are rooted at several levels within a thin (15-40 cm) bone coal directly above the banded coal; they extend upward up to 15 cm into overlying, flat-bedded, carbonaceous mudstones that coarsen up. From a maximum basal diameter of 1.2 m, stumps taper upward to diameters no less than 0.3 m. Within single-entry transects, < 6 m wide that total 2585 m in length, stumps are randomly distributed. The trees are identified as lepidodendrids on the basis of gross morphology, external stem patterns, and attached stigmarian root systems, and provisionally as Lepidophloios or Lepidodendron by associated palynology of the enclosing matrix. Palynological analyses of incremental seam samples indicate an initial dominance of lycopsid spores with lepidodendracean affinities (Lycospora granulata from Lepidophloios hallii), replaced upwards by tree-fern spores, with a reoccurrence of lepidodendracean spores in the upper benches; spores of Sigillaria (Crassispora) are abundant only at the base of the coal. Petrographic analyses indicate a parallel trend from vitrinite-rich to inertinite- and liptinite-rich upward in the coal body. All data indicate that the peat represented by the Mahoning coal was drowned slowly. During the earliest stages of inundation, a lycopsid forest was re-established, only to be subsequently drowned.

Degradation of mangrove tissues and implications for peat formation in Belizean island forests

USGS Publications Warehouse

Middleton, B.A.; McKee, K.L.

2001-01-01

1. Macrofaunal leaf consumption and degradation of leaves, woody twigs and roots were studied in mangrove island forests on a Belizean island. Factors influencing accumulation of organic matter deposited both above and below ground in this oligotrophic, autochothonous system were assessed. 2. Leaf degradation rates of Rhizophora mangle (red mangrove), Avicennia germinans (black mangrove) and Laguncularia racemosa (white mangrove) measured in mesh bags, were much faster in the lower than the upper intertidal zone. Mass loss was most rapid in A. germinans but zonal effects were much larger than species differences. 3. Exposure to invertebrates such as crabs and amphipods tripled overall rates of leaf litter breakdown. In the lower intertidal, crabs completely consumed some unbagged leaves within 23 days. Crabs also had an effect on some upper intertidal sites, where degradation of leaves placed in artificial burrows was 2.4 times faster than when placed on the soil surface. 4. In contrast to leaves (27??5% remaining after 230 days), roots and woody twigs were highly refractory (40??2% and 51??6% remaining after 584 and 540 days, respectively). Root degradation did not vary by soil depth, zone or species. Twigs of R. mangle and A. germinans degraded faster on the ground than in the canopy, whereas those of L. racemosa were highly resistant to decay regardless of position. 5. Peat formation at Twin Cays has occurred primarily through deposition and slow turnover of mangrove roots, rather than above-ground tissues that are either less abundant (woody twigs) or more readily removed (leaves).

A Study on Factors Affecting Strength of Solidified Peat through XRD and FESEM Analysis

NASA Astrophysics Data System (ADS)

Rahman, J. A.; Napia, A. M. A.; Nazri, M. A. A.; Mohamed, R. M. S. R.; Al-Geethi, A. S.

2018-04-01

Peat is soft soil that often causes multiple problems to construction. Peat has low shear strength and high deformation characteristics. Thus, peat soil needs to be stabilized or treated. Study on peat stabilization has been conducted for decades with various admixtures and mixing formulations. This project intends to provide an overview of the solidification of peat soil and the factors that affecting the strength of solidified peat soil. Three types of peats which are fabric, hemic and sapric were used in this study to understand the differences on the effect. The understanding of the factors affecting strength of solidified peat in this study is limited to XRD and FESEM analysis only. Peat samples were collected at Pontian, Johor and Parit Raja, Johor. Peat soil was solidified using fly ash, bottom ash and Portland cement with two mixing formulation following literature review. The solidified peat were cured for 7 days, 14 days, 28 days and 56 days. All samples were tested using Unconfined Compressive Strength Test (UCS), X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM). The compressive strength test of solidified peat had shown consistently increase of sheer strength, qu for Mixing 1 while decrease of its compressive strength value for Mixing 2. All samples were tested and compared for each curing days. Through XRD, it is found that all solidified peat are dominated with pargasite and richterite. The highest qu is Fabric Mixing 1(FM1) with the value of 105.94 kPa. This sample were proven contain pargasite. Samples with high qu were observed to be having fly ash and bottom ash bound together with the help of pargasite. Sample with decreasing strength showed less amount of pargasite in it. In can be concluded that XRD and FESEM findings are in line with UCS values.

The Record of Tsunamis and Storms in a Coastal Mangrove Pond, NW Puerto Rico

NASA Astrophysics Data System (ADS)

Jaffe, B. E.; Buckley, M. L.; Watt, S. G.; Moya, J. C.; Richmond, B. M.; Gelfenbaum, G. R.; La Selle, S.

2017-12-01

The written record of tsunamis in the Caribbean extends back over 500 years, yet, is incomplete. In particular, it is not known whether great earthquakes or submarine landslides near the Puerto Rico Trench have generated large tsunamis that impact the north coast of Puerto Rico. We cored a coastal mangrove pond in NW Puerto Rico to search for tsunami deposits. The pond extends from 150 to 350 m from the shoreline, and is 0.5 m above sea level. The area between the pond and the ocean presently has a high of 3 m above sea level, but had dunes up to 10 m high before they were mined for sand beginning in the 1960s. Pond sediments are predominately mud or mangrove peat and contain prominent sand layers. At the sediment surface, a tabular sandy overwash deposit up to 40 cm thick extends inland approximately 30 m from the pond's seaward edge and abruptly ends. This sand layer contains no evidence of vertical grading and was likely formed by one or more recent hurricanes, which with the removal of coastal dunes in the 1960s are able to flood the pond. In contrast, underlying the overwash deposit and mangrove peat at a depth of approximately 60 cm is a thin (1 - 7 cm thick) sand layer extending to the landward limit of the pond. This layer has features of a tsunami deposit, including suspension grading, which is a specific type of normal grading where the entire grain-size distribution shifts to finer sizes upward that is created when sediment settles out of suspension as a high-speed flow wanes, an erosive basal contact, and an organic cap. In addition, couplets or triplets of sand inter-layered with mud are present within the thin sandy layer at some locations. Alternation of sand and mud layers at this scale is a signature of series of tsunami waves. Radiocarbon dates from organic material above and below the thin sand layer constrain deposition as occurring sometime from 1446 to 1919 AD. We present the features of the coastal mangrove pond deposits and evaluate whether these deposits could be correlated with an extreme wave overwash that left a deposit on Anegada, BVI, sometime between 1200 and 1480 AD, which would support a great Puerto Rico Trench earthquake and tsunami about 600 years ago.

Soils of the Southwestern Part of the Pacific Coast of Russia

NASA Astrophysics Data System (ADS)

Kostenkov, N. M.; Zharikova, E. A.

2018-02-01

The diversity of soils in the southwestern part of the Pacific coast of Russia (Primorie region) is discussed. Overall, 17 soil types belonging to 8 soil orders have been described in this region, and their morphology and properties have been studied. The diversity of plant communities, geomorphic conditions, and parent materials and relatively mild (as compared with other parts of the Far East region of Russia) specify the great variability of soil cover patterns. Low sea terraces are occupied by various peat, organo-accumulative, and gley soils; poorly drained medium-high terraces are the areas of various dark-humus and darkhumus gleyed soils. Typical and gleyic dark-humus podbels, dark-humus, and dark-humus gleyed soils formed on the high sea terraces. Residual elevations are occupied by brown forest (burozemic) soils, including typical burozems, dark-humus burozems, and gleyic dark-humus burozems and by dark-humus podbels. Various alluvial, gleyic gray-humus, and mucky gley soils are developed on riverine plains. On general, darkhumus soils with the high (>10%) humus content predominate; the area of dark-humus podbels us estimated at about 20%, and the area of dark-humus burozems is about 12%. All the soils in this region are specified by increased acidity values. The exchangeable sodium content is often high in the upper soil horizons with maximum values (0.71-1.19 cmol(c)/kg) in the peat gleyzems, peaty dark-humus soils, mucky-gley soils, and eutrophic peat soils of sea terraces. The grouping of the soils with respect to their physicochemical and agrochemical properties is suggested.

Peat

USGS Publications Warehouse

Apodaca, Lori E.

2013-01-01

The article looks at the U.S. peat market as of July 2013. Peat is produced from deposits of plant organic materials in wetlands and includes varieties such as reed-sedge, sphagnum moss, and humus. Use for peat include horticultural soil additives, filtration, and adsorbents. Other topics include effects of environmental protection regulations on peat extraction, competition from products such as coir, composted organic waste, and wood products, and peatland carbon sinks.

Spatial-temporal controls on peatland carbon dynamics in the Hudson Bay Lowland, Canada: Reducing landscape-scale uncertainty in a changing climate

NASA Astrophysics Data System (ADS)

Packalen, M. S.; Finkelstein, S. A.; McLaughlin, J.

2015-12-01

Global peatlands currently store more than 650 Pg of carbon (C) that has accumulated over millennia, and contributed to a net climatic cooling. However, controls on spatial-temporal C dynamics may differ regionally. With at least 30 Pg C sequestered in the Hudson Bay Lowlands Canada (HBL), the vulnerability of this globally significant peat C reservoir remains uncertain under conditions of a changing climate and enhanced anthropogenic pressure. Here, we synthesize our current understanding of controls on C dynamics in the HBL using detailed peat records. Our data reveal that widespread bog-fen patterning across the HBL is related to the distribution of peat C in space and time, indicating that topographic and ecohydroclimatic controls are potentially important determinants of C mass accretion. We find that while peat age is closely related to timing of land emergence and peat depth in the HBL, considerable variation in the total C mass among sites of similar peat age suggests that additional factors may further explain trends in peat C dynamics. Among these factors, we find that temperature, precipitation, and potential evapotranspiration in the HBL account for up to half of the variation in the distribution of the peat C mass, whereby regions with warmer and wetter conditions support larger peat C masses. Moreover, we find that the rate of C accumulation is greatest for young fen peatlands developing during warmer mid-Holocene climates; but that long-term C stores are greatest in association with bog peatlands. Although nearly two-thirds of HBL peat C is of late Holocene age, most of the reconstructed potential C losses also occurred during the late Holocene, as previously accrued peat decayed. Our findings support the hypothesis that both climate and ecohydrological factors are important drivers of peat C dynamics in the HBL, alongside geophysical controls on the timing of peat initiation. As the HBL peat complex continues to rapidly expand, it may remain a globally significant C reservoir. However, conservative climate scenarios predict warmer and wetter conditions in the next century, beyond the range of past climate variability. Ongoing elucidation of controls on peat C dynamics may further inform our understanding of the response of the HBL peat C reservoir to future climate and resource management scenarios.

A reconstruction of vegetation and paleohydrologycal changes from peatland in Kansk forest-steppe, Yenisei Siberia

NASA Astrophysics Data System (ADS)

Rodionova, Alexandra

2016-04-01

Peatlands are an important natural archive for past climatic changes. Climatic changes throughout the Holocene have been reconstructed from peat using a wide array of biological and other proxies. Many different proxy indicators can be derived from peat cores allowing for a multi-proxy approach to climatic reconstructions. Peat-based climatic and environmental reconstructions are currently available from many sites in Yenisei Siberia, mainly for its northern territories. The purpose of this paper is to study some features of peatland development and environmental reconstructions from the Holocene period in the south part of Yenisei Siberia (Kansk forest-steppe zone). The main method used in this research is macrofossil analysis. It can be used to reconstruct the development of local vegetation and surface wetness on peatlands. The macrofossil analysis in the peat resulted from the study of the vegetation in a particular place over a period of time, and it allowed the reconstruction of environmental changes that have occurred since the Late Glacial. Then we used ecological scales of moisture and reconstructed surface wetness for the entire period of the bog formation. Radiocarbon dating was carried out at Sobolev Institute of Geology and Mineralogy, Russian Academy of Sciences, Novosibirsk . Peatland "Pinchinskoye" was selected for investigation in Kansk forest-steppe. It is located on the right bank of the Yenisei River in the floodplain of Esaulovka River. Peat cores of 350 cm were selected in the southern part of the peatbog, including 225 cm of peat (with loam layers in the range of 90 to 135 cm), 75 cm of organic and mineral sapropel with the inclusion of fossil shells of mollusks and different plant macrofossils and 50 cm of the loam below. The process of peat accumulation dated back 8400 ± 140 years, which is the oldest date for the forest-steppe zone of Yenisei Siberia. The climate of Boreal period of the Holocene was chilly. Under these conditions, in the territory of the peatland "Pinchinskoye" there was a small lake. The birch forest with different grasses was growing along the banks of the lake. The lake level dropped significantly at the beginning of the Atlantic period around 7000 BP in a warm and dry climate. This launched the lake overgrowth and eutrophication. Birch forests and then spruce forests rich in herbs with green moss emerged in the peatland. An increase in moisture was recorded for the Sub-Boreal period (4900-2400) and, as a result, the prevalence of marsh communities with bog bean and fern. Increasing water level of rovers led to the spill and silting up of the bog surface in 2020 ± 60 BP at the beginning of the Sub-Atlantic period. After the decline of the water level, the process of peat accumulation continued and spread out throughout the whole trough flat. Sedge, cotton grass, sphagnum moss and green moss predominated in the composition of plant communities in Sub-Atlantic period, starting from 1500 BP. In the last 500 years, the peatland moved to the mesoeutrophic phase of development.

Investigation of bacterial communities in peat land of the Gahai Lake natural conservation area

NASA Astrophysics Data System (ADS)

Bai, Yani; Wang, Jinchang; Zhan, Zhigao; Guan, Limei; Jin, Liang; Zheng, Guohua

2017-10-01

Peat is involved in the global carbon cycle and water conservation; therefore, it is implicated in global environmental change. Microorganisms play an important role in the function of peat. To investigate the bacterial communities in peat of Gahai Lake, different locations and depths were sampled and Illumina Miseq sequencing was used to analyze the microbial community. Chemical properties of peat samples were analyzed by China state standard methods (GB methods). The results showed that bacterial communities were affected by depth, with bacterial diversity and community structure at 90 and 120 cm significantly different from that at 10, 30 and 50 cm depth from the peat surface. Chemical properties of peat land including organic matter, total nitrogen and humus content did not significantly influence bacterial community structure in peat, with only one group from genus Rhizomicrobium that was significantly correlated with total nitrogen. A substantial proportion of the bacterial sequences were unclassified (1.4%), which indicates the great application potential of peat in the Gahai Lake natural conservation area in the future.

Physical and chemical characteristics of fibrous peat

NASA Astrophysics Data System (ADS)

Sutejo, Yulindasari; Saggaff, Anis; Rahayu, Wiwik; Hanafiah

2017-11-01

Banyuasin is one of the regency in South Sumatera which has an area of 200.000 Ha of peat land. Peat soil are characterized by high compressibility parameters and low initial shear strength. Block sampling method was used to obtain undisturbed sample. The results of this paper describe the characteristics of peat soil from physical and chemical testing. The physical and chemical characteristics of peat include water content (ω), specific gravity (Gs), Acidity (pH), unit weight (γ), and ignition loss tests. SEM and EDS test was done to determine the differences in fiber content and to analyze chemical elements of the specimen. The average results ω, Gs, and pH are 263.538 %, 1.847, and 3.353. Peat is classified in H4 (by Von Post). The results of organic content (OC), ash content (AC), and fiber content (FC) are found 78.693 %, 21.310 %, and 73.703 %. From the results of physical and chemical tests, the peat in Banyuasin is classified as fibrous peat. All the results of the characteristics and classification of fibrous peat compared with published data were close.

Tropical/Subtropical Peatland Development and Global CH4 during the Last Glaciation.

PubMed

Xu, Hai; Lan, Jianghu; Sheng, Enguo; Liu, Yong; Liu, Bin; Yu, Keke; Ye, Yuanda; Cheng, Peng; Qiang, Xiaoke; Lu, Fengyan; Wang, Xulong

2016-07-28

Knowledge of peatland development over the tropical/subtropical zone during the last glaciation is critical for understanding the glacial global methane cycle. Here we present a well-dated 'peat deposit-lake sediment' alternate sequence at Tengchong, southwestern China, and discuss the peatland development and its linkage to the global glacial methane cycle. Peat layers were formed during the cold Marine Isotope Stage (MIS)-2 and -4, whereas lake sediments coincided with the relatively warm MIS-3, which is possibly related to the orbital/suborbital variations in both temperature and Asian summer monsoon intensity. The Tengchong peatland formation pattern is broadly synchronous with those over subtropical southern China and other tropical/subtropical areas, but it is clearly in contrast to those over the mid-high Northern Hemisphere. The results of this work suggest that the shifts of peatland development between the tropical/subtropical zone and mid-high Northern Hemisphere may have played important roles in the glacial/interglacial global atmospheric CH4 cycles.

Tropical/Subtropical Peatland Development and Global CH4 during the Last Glaciation

PubMed Central

Xu, Hai; Lan, Jianghu; Sheng, Enguo; Liu, Yong; Liu, Bin; Yu, Keke; Ye, Yuanda; Cheng, Peng; Qiang, Xiaoke; Lu, Fengyan; Wang, Xulong

2016-01-01

Knowledge of peatland development over the tropical/subtropical zone during the last glaciation is critical for understanding the glacial global methane cycle. Here we present a well-dated ‘peat deposit-lake sediment’ alternate sequence at Tengchong, southwestern China, and discuss the peatland development and its linkage to the global glacial methane cycle. Peat layers were formed during the cold Marine Isotope Stage (MIS)-2 and -4, whereas lake sediments coincided with the relatively warm MIS-3, which is possibly related to the orbital/suborbital variations in both temperature and Asian summer monsoon intensity. The Tengchong peatland formation pattern is broadly synchronous with those over subtropical southern China and other tropical/subtropical areas, but it is clearly in contrast to those over the mid-high Northern Hemisphere. The results of this work suggest that the shifts of peatland development between the tropical/subtropical zone and mid-high Northern Hemisphere may have played important roles in the glacial/interglacial global atmospheric CH4 cycles. PMID:27465566

An unusual occurrence of arsenic-bearing pyrite in the Upper Freeport coal bed, West-Central Pennsylvania

USGS Publications Warehouse

Ruppert, L.F.; Minkin, J.A.; McGee, J.J.; Cecil, C.B.

1992-01-01

Scanning electron microscopy and electron microprobe analysis were used to identify a rare type of As-bearing pyrite in selected specific gravity separates from the Pennsylvanian age Upper Freeport coal bed, west-central Pennsylvania. Arsenic was detected mainly in cell-wall replacement pyrite where concentrations ranged from nondetectable to 1.9 wt %. Although the majority of arsenic-bearing pyrite in the Upper Freeport coal bed is concentrated in massive and late diagenetic pyrite morphologies, the rarer As-bearing cell-replacement pyrite was observed in both light and heavy gravity separates from the three coal facies examined. Arsenic was occasionally detected in cell-filling replacement pyrite, but this As appears to be an artifact produced by signals from underlying and/or adjacent As-bearing cell-wall replacement pyrite. It is postulated that some plants of the Upper Freeport paleoswamp may have biomethylated As, which later could have been converted to dimethylarsine or other volatile organoarsenic compounds by either biologically or chemically driven processes. Once liberated, the arsenic may have been incorporated into pyrite during pyritization of the cell walls. The As incorporation occurred early, before significant compaction of the peat, because the pyritized cell walls are not compacted.

Development and carbon sequestration of tropical peat domes in south-east Asia: links to post-glacial sea-level changes and Holocene climate variability

NASA Astrophysics Data System (ADS)

Dommain, René; Couwenberg, John; Joosten, Hans

2011-04-01

Tropical peatlands of SE-Asia represent a significant terrestrial carbon reservoir of an estimated 65 Gt C. In this paper we present a comprehensive data synthesis of radiocarbon dated peat profiles and 31 basal dates of ombrogenous peat domes from the lowlands of Peninsular Malaysia, Sumatra and Borneo and integrate our peatland data with records of past sea-level and climate change in the region. Based on their developmental features three peat dome regions were distinguished: inland Central Kalimantan (Borneo), Kutai basin (Borneo) and coastal areas across the entire region. With the onset of the Holocene the first peat domes developed in Central Kalimantan as a response to rapid post-glacial sea-level rise over the Sunda Shelf and intensification of the Asian monsoon. Peat accumulation rates in Central Kalimantan strongly declined after 8500 cal BP in close relation to the lowering rate of the sea-level rise and possibly influenced by the regional impact of the 8.2 ka event. Peat growth in Central Kalimantan apparently ceased during the Late Holocene in association with amplified El Niño activity as exemplified by several truncated peat profiles. Peat domes from the Kutai basin are all younger than ˜8300 cal BP. Peat formation and rates of peat accumulation were driven by accretion rates of the Mahakam River and seemingly independent of climate. Most coastal peat domes, the largest expanse of SE-Asian peatlands, initiated between 7000 and 4000 cal BP as a consequence of a Holocene maximum in regional rainfall and the stabilisation and subsequent regression of the sea-level. These boundary conditions induced the highest rates of peat accumulation of coastal peat domes. The Late Holocene sea-level regression led to extensive new land availability that allowed for continued coastal peat dome formation until the present. The time weighted mean Holocene peat accumulation rate is 0.54 mm yr -1 for Central Kalimantan, 1.89 mm yr -1 for Kutai and 1.77 mm yr -1 for coastal domes of Sumatra and Borneo. The mean Holocene carbon sequestration rates amount to 31.3 g C m -2 yr -1 for Central Kalimantan and 77.0 g C m -2 yr -1 for coastal sites, which makes coastal peat domes of south-east Asia the spatially most efficient terrestrial ecosystem in terms of long term carbon sequestration.

Peat

USGS Publications Warehouse

Jasinski, S.M.

2006-01-01

In 2005, peat was harvested in 15 US states. Florida, Michigan and Minnesota accounted for more than 80% of the US production. Reed-sedge was the dominant variety of peat harvested in the United States. More than 56% of all peat used in the US was imported from Canada. With the growing interest in gardening, landscaping related to home construction and golf courses, peat usage is expected to remain near current levels during the next several years.

Influence of peat formation conditions on the transformation of peat deposit organic matter

NASA Astrophysics Data System (ADS)

Serebrennikova, O. V.; Strelnikova, E. B.; Preis, Yu I.; Duchko, M. A.

2015-11-01

The paper studies the individual composition of n-alkanes, polycycloaromatic hydrocarbons, steroids, bi-, tri-, and pentacyclic terpenoids of two peat deposits of rich fen Kirek located in Western Siberia. Considering the individual n-alkanes concentrations, some indexes were calculated to estimate the humidity during peat formation. It was shown that the pH of peat medium primarily affects steroids, tri- and pentacyclic terpenoids transformations.

Content of radionuclides in the peat deposit of swamps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nifontova, M.G.; Makovskii, V.I.

1995-11-01

The results are given of comparative analysis of the content and transformation of {sup 90}Sr and {sup 137}Cs over a peat deposit of swamps. During radioecological study, account was taken of the quantitative composition and physicochemical properties of the peat, as well as of the specific nature of the entry of radioactive products to peat deposits. Considering the increased capacity of peat for accumulating radionuclides and the specific features of sorption processes in a peat deposit, it is expedient to utilize swamps as a convenient natural object for continuous monitoring of radioactive contamination of the environment.

Micropetrographic characteristics of peats from modern coal-forming environments in Okefenokee Swamp, Georgia and Albemarle-Pamlico Peninsular Swamps, North Carolina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corvinus, D.A.

1982-01-01

The Okefenokee Swamp, over 400,000 acres, is a swamp-marsh complex dominated by Taxodium-swamp vegetaion on its west side and Nymphaea-marsh vegetation onits east side. The Albemarle-Pamlico Peninsular Swamps primarily support a pocosin-bay vegetation. The Taxodium-dominated peats of the Okefenokee are more similar botanically to the Albemarle-Pamlico bay peats than are the Okefenokee Nymphaea-dominated peats. Some petrographic characteristics are common to all three peat types. The majority of cell walls in the peat exhibit colors (yellow to orange to red) which they did not display in their living state. This is believed to be from impregnation by the various cell fillingsmore » present in the peats. Unoxidized fragmented (granular) material in all three peat types usually occurs in larger amounts than oxidized (darkened) material. In Taxodium-dominated and bay peats the fragmented matrix is also usually more prevalent than the preserved material (intact cell walls and cell fillings). On the other hand, preserved material is most common in Nymphaea-dominated peats. It is believed that the majority of fragmented material is derived from the surface litter and that swamp vegetation contributes more surface litter than does marsh vegetation.« less

Emissions of volatile organic compounds and particulate matter from small-scale peat fires

NASA Astrophysics Data System (ADS)

George, I. J.; Black, R.; Walker, J. T.; Hays, M. D.; Tabor, D.; Gullett, B.

2013-12-01

Air pollution emitted from peat fires can negatively impact regional air quality, visibility, climate, and human health. Peat fires can smolder over long periods of time and, therefore, can release significantly greater amounts of carbon into the atmosphere per unit area compared to burning of other types of biomass. However, few studies have characterized the gas and particulate emissions from peat burning. To assess the atmospheric impact of peat fires, particulate matter (PM) and volatile organic compounds (VOCs) were quantified from controlled small-scale peat fire experiments. Major carbon emissions (i.e. CO2, CO, methane and total hydrocarbons) were measured during the peat burn experiments. Speciated PM mass was also determined from the peat burns from filter and polyurethane foam samples. Whole air samples were taken in SUMMA canisters and analyzed by gas chromatography-mass spectrometry to measure 82 trace VOCs. Additional gaseous carbonyl species were measured by sampling with dinitrophenylhydrazine-coated cartridges and analyzed with high performance liquid chromatography. VOCs with highest observed concentrations measured from the peat burns were propylene, benzene, chloromethane and toluene. Gas-phase carbonyls with highest observed concentrations included acetaldehyde, formaldehyde and acetone. Emission factors of major pollutants will be compared with recommended values for peat and other biomass burning.

Can a novel combination of organic chemical analysis and inverse modeling help reconstruct the past upper forest line in the Ecuadorian Andes?

NASA Astrophysics Data System (ADS)

Jansen, B.; van Loon, E. E.; Nierop, K. G. J.

2009-04-01

The higher parts of the Ecuadorian Andes consist of fragile ecosystems characterized by páramo grasslands and montane cloud forests. Natural climatic change and human interference (i.a. burning and clear-cutting) are believed to have dramatically lowered the UFL in the area to the point that its natural position in the absence of disturbance is now uncertain. This is impeding our understanding of the response of the UFL to global climate change and hindering a correct strategy to reforest areas in the frame of Kyoto Protocol driven activities to fix carbon dioxide. An important cause of the uncertainty is that the traditional method of pollen analysis from peat or sediment deposits alone does not suffice to reconstruct shifts in the UFL. Reasons are the spatial uncertainty caused by wind-blown dispersal of pollen and the limited availability of peat or sediment deposits at all altitudes of interest. The RUFLE* program tackles this problem by combining traditional pollen and vegetation analyses with a novel biomarker approach. In the latter, plant species typical for specific vegetation zones are examined for the presence of biomarkers, defined as plant-specific (combinations of) organic chemical components. Our results show that the leaves and roots of the higher plants responsible for the dominant biomass input in our study area in the Eastern Cordillera in the Northern Ecuadorian Andes contain unique combinations of n-alkanes and n-alcohols in the carbon number range of C20-C36(1). Furthermore, we found these compounds to be well preserved in peat deposits and soils in chronological order for extended time periods (>6000 14C years B.P.)(2,3). As such they offer great potential to serve as biomarkers for past vegetation dynamics, including UFL shifts. However, since it are unique combinations of otherwise ubiquitous n-alkanes, n-alcohols of various carbon chain-lengths that constitute our biomarkers, unraveling the mixed signal of various plants accumulated in soils and peat sediment over time poses a major challenge. To tackle this problem, we developed the VERHIB model that describes the accumulation of biomarkers in soils and peat sediments(4). By inversion the most likely vegetation composition leading to the mixed biomarker signal in the soil or peat sediment in question can be derived. Here we describe the results of the first application of the model in a peat core and several soil monoliths at various altitudes from our study area. Our results show that biomarker analysis using the VERHIB model can indeed serve as a new proxy to reconstruct historic vegetation compositions including the UFL in the Ecuadorian Andes, yielding information that is highly complementary to that which can be obtained through traditional pollen analysis. This is a significant breakthrough from a paleo-ecological point of view as it means an additional proxy is available to be used in combination with traditional pollen- and vegetation analysis. In addition, it is a very promising result from an applied point of view as the information gained will aid the Ecuadorian government in its strategic decisions concerning reforestation of possibly degraded natural areas. 1)Jansen, B. Nierop, K.G.J., Hageman, J.A., Cleef, A.M. & Verstraten, J.M. 2006. The straight chain lipid biomarker composition of plant species responsible for the dominant biomass production along two altitudinal transects in the Ecuadorian Andes. Organic Geochemistry 37: 1514-1536. 2)Jansen, B. & Nierop, K.G.J. 2008. Methyl ketones in high altitude Ecuadorian Andosols confirm excellent conservation of plant-specific n-alkane patterns. Organic Geochemistry (in press). 3)Tonneijck, F.H. & Jongmans, A.G. 2008. The influence of bioturbation on the vertical distribution of soil organic matter in volcanic ash soils: a case study in Northern Ecuador. European Journal of Soil Science 59: 1063-1075. 4)Jansen, B., Van Loon, E.E., Hooghiemstra, H. & Verstraten, J.M. 2008. Analysis of plant biomarkers greatly improves reconstruction of palaeo-environments. Geology (submitted). *RUFLE stands for Reconstruction of the Upper Forest Line in Ecuador

The peats of Costa Rica (in English; Spanish)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thayer, G.R.

Peat has been identified in Cost Rica, and an economic analysis of energy applications for peat has been done. About 1000 km{sup 2} of Cost Rica has the potential of being covered by peat. The Talamanca Mountains and the northeastern plains contain most of the Costa Rican peat. Specific bogs have been identified by the Medio Queso River in north-central Costa Rica and near El Cairo, Moin, and the Limon airport in northeastern Costa Rica. The Medio Queso bog, which is supplying peat for use as a carrier for nitrogen-fixing bacteria, and the El Cairo bog, which has been identifiedmore » as a source of horticultural peat for nearby ornamental plant farms, are of special interest. The economics of three energy applications of peat were examined -- as a fuel in large boilers, as a fuel in small boilers, and as an oil substitute in a cement plant. A facility using coal would have the same total costs as one using peat if coal prices were $45 and $30 per metric ton (used for large boilers and a cement plant, respectively). A facility using Bunker C or diesel would have the same total cost as one using peat if oil prices were $0.11, $0.08, and $0.06 per liter (used for large boilers, small boilers, and a cement plant, respectively). In all three cases, the costs for peat were comparable or less than the costs for coal and oil at 1987 prices. 6 refs., 8 figs.« less

Microbial biomass and basal respiration in Sub-Antarctic and Antarctic soils in the areas of some Russian polar stations

NASA Astrophysics Data System (ADS)

Abakumov, E.; Mukhametova, N.

2014-03-01

Antarctica is the unique place for pedological investigations. Soils of Antarctica have been studied intensively during the last century. Antarctic logistic provides the possibility to scientists access the terrestrial landscapes mainly in the places of polar stations. That is why the main and most detailed pedological investigations were conducted in Mc Murdo Valleys, Transantarctic Mountains, South Shetland Islands, Larsemann hills and Schirmacher Oasis. Investigations were conducted during the 53rd and 55th Russian Antarctic expeditions on the base of soil pits and samples collected in Sub-Antarctic and Antarctic regions. Soils of diverse Antarctic landscapes were studied with aim to assess the microbial biomass level, basal respiration rates and metabolic activity of microbial communities. The investigation conducted shows that soils of Antarctic are quite different in profile organization and carbon content. In general, Sub-Antarctic soils are characterized by more developed humus (sod) organo-mineral horizons as well as the upper organic layer. The most developed organic layers were revealed in peat soils of King-George Island, where its thickness reach even 80 cm. These soils as well as soils under guano are characterized by the highest amount of total organic carbon (TOC) 7.22-33.70%. Coastal and continental soils of Antarctic are presented by less developed Leptosols, Gleysols, Regolith and rare Ornhitosol with TOC levels about 0.37-4.67%. The metabolic ratios and basal respiration were higher in Sub-Antarctic soils than in Antarctic ones which can be interpreted as result of higher amounts of fresh organic remnants in organic and organo-mineral horizons. Also the soils of King-George island have higher portion of microbial biomass (max 1.54 mg g-1) than coastal (max 0.26 mg g-1) and continental (max 0.22 mg g-1) Antarctic soils. Sub-Antarctic soils mainly differ from Antarctic ones in increased organic layers thickness and total organic carbon content, higher microbial biomass carbon content, basal respiration and metabolic activity levels.

Landscape-scale changes in forest canopy structure across a partially logged tropical peat swamp

NASA Astrophysics Data System (ADS)

Wedeux, B. M. M.; Coomes, D. A.

2015-07-01

Forest canopy structure is strongly influenced by environmental factors and disturbance, and in turn influences key ecosystem processes including productivity, evapotranspiration and habitat availability. In tropical forests increasingly modified by human activities, the interplaying effects of environmental factors and disturbance legacies on forest canopy structure across landscapes are practically unexplored. We used high-fidelity airborne laser scanning (ALS) data to measure the canopy of old-growth and selectively logged peat swamp forest across a peat dome in Central Kalimantan, Indonesia, and quantified how canopy structure metrics varied with peat depth and under logging. Several million canopy gaps in different height cross-sections of the canopy were measured in 100 plots of 1 km2 spanning the peat dome, allowing us to describe canopy structure with seven metrics. Old-growth forest became shorter and had simpler vertical canopy profiles on deeper peat, consistently with previous work linking deep peat to stunted tree growth. Gap Size Frequency Distributions (GSFDs) indicated fewer and smaller canopy gaps on the deeper peat (i.e. the scaling exponent of pareto functions increased from 1.76 to 3.76 with peat depth). Areas subjected to concessionary logging until 2000, and informal logging since then, had the same canopy top height as old-growth forest, indicating the persistence of some large trees, but mean canopy height was significantly reduced; the total area of canopy gaps increased and the GSFD scaling exponent was reduced. Logging effects were most evident on the deepest peat, where nutrient depletion and waterlogged conditions restrain tree growth and recovery. A tight relationship exists between canopy structure and the peat deph gradient within the old-growth tropical peat swamp. This relationship breaks down after selective logging, with canopy structural recovery being modulated by environmental conditions.

The Impact of Tropical Peat Fire on Termite Assemblage in Sumatra, Indonesia: Reduced Complexity of Community Structure and Survival Strategies.

PubMed

Neoh, Kok-Boon; Bong, Lee-Jin; Muhammad, Ahmad; Itoh, Masayuki; Kozan, Osamu; Takematsu, Yoko; Yoshimura, Tsuyoshi

2016-10-01

Tropical peat swamp forests in Southeast Asia account for approximately 72% of global peatland. However, extensive forest exploitation following peat drainage for agricultural expansion has been leading to catastrophic peat fires. In this study, we compared the termite assemblage in burnt and unburnt peats in Sumatra, Indonesia. We also identified which taxonomic group is particularly resistant to fire disturbance and the traits that correlate with its persistence in fire-impacted peatlands. Overall, the termite species richness in fire-impacted peats was up to 40% lower than that of the total species found in peat swamp forests. Although the estimated species richness values in fire-impacted peats and peat swamp forests were not significantly different, fire changed termite community structure significantly. Only termites of the family Rhinotermitidae survived in the fire event, whereas members of the Termitidae that were reportedly resilient to fire and open habitats elsewhere disappeared during the fire events. The rhinotermitids found in the burnt sites were exclusively wood nesters. This suggests that the desiccation tolerance of termites in open habitat is not the simple underlying survival strategy, but tree branches and barks might have provided a refuge from heat during fire. The result also suggests that the high similarity in species composition in recently burnt peats and long burnt peats implies low species turnover. Thus, regardless of how much time had passed since the fire-impacted peats were abandoned or cultivated, the increase in habitat complexity did not favor colonization by the forest-dependent group. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Arctic Ocean Model Intercomparison Using Sound Speed

NASA Astrophysics Data System (ADS)

Dukhovskoy, D. S.; Johnson, M. A.

2002-05-01

The monthly and annual means from three Arctic ocean - sea ice climate model simulations are compared for the period 1979-1997. Sound speed is used to integrate model outputs of temperature and salinity along a section between Barrow and Franz Josef Land. A statistical approach is used to test for differences among the three models for two basic data subsets. We integrated and then analyzed an upper layer between 2 m - 50 m, and also a deep layer from 500 m to the bottom. The deep layer is characterized by low time-variability. No high-frequency signals appear in the deep layer having been filtered out in the upper layer. There is no seasonal signal in the deep layer and the monthly means insignificantly oscillate about the long-period mean. For the deep ocean the long-period mean can be considered quasi-constant, at least within the 19 year period of our analysis. Thus we assumed that the deep ocean would be the best choice for comparing the means of the model outputs. The upper (mixed) layer was chosen to contrast the deep layer dynamics. There are distinct seasonal and interannual signals in the sound speed time series in this layer. The mixed layer is a major link in the ocean - air interaction mechanism. Thus, different mean states of the upper layer in the models might cause different responses in other components of the Arctic climate system. The upper layer also strongly reflects any differences in atmosphere forcing. To compare data from the three models we have used a one-way t-test for the population mean, the Wilcoxon one-sample signed-rank test (when the requirement of normality of tested data is violated), and one-way ANOVA method and F-test to verify our hypothesis that the model outputs have the same mean sound speed. The different statistical approaches have shown that all models have different mean characteristics of the deep and upper layers of the Arctic Ocean.

Influence of mid-crustal rheology on the deformation behavior of continental crust in the continental subduction zone

NASA Astrophysics Data System (ADS)

Li, Fucheng; Sun, Zhen; Zhang, Jiangyang

2018-06-01

Although the presence of low-viscosity middle crustal layer in the continental crust has been detected by both geophysical and geochemical studies, its influence on the deformation behavior of continental crust during subduction remains poorly investigated. To illustrate the crustal deformation associated with layered crust during continental subduction, we conducted a suite of 2-D thermo-mechanical numerical studies with visco-brittle/plastic rheology based on finite-differences and marker-in-cell techniques. In the experiments, we established a three-layer crustal model with a quartz-rich middle crustal layer embedded between the upper and lower continental crust. Results show that the middle crustal layer determines the amount of the accreted upper crust, maximum subduction depth, and exhumation path of the subducted upper crust. By varying the initial effective viscosity and thickness of the middle crustal layer, the further effects can be summarized as: (1) a rheologically weaker and/or thicker middle crustal layer results in a larger percentage of the upper crust detaching from the underlying slab and accreting at the trench zone, thereby leading to more serious crustal deformation. The rest of the upper crust only subducts into the depths of high pressure (HP) conditions, causing the absence of ultra-high pressure (UHP) metamorphic rocks; (2) a rheologically stronger and/or thinner middle crustal layer favors the stable subduction of the continental crust, dragging the upper crust to a maximum depth of ∼100 km and forming UHP rocks; (3) the middle crustal layer flows in a ductile way and acts as an exhumation channel for the HP-UHP rocks in both situations. In addition, the higher convergence velocity decreases the amount of subducted upper crust. A detailed comparison of our modeling results with the Himalayan collisional belt are conducted. Our work suggests that the presence of low-viscosity middle crustal layer may be another possible mechanism for absence of UHP rocks in the southern Tibet.

Photovoltaic module and laminate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunea, Gabriela E.; Kim, Sung Dug; Kavulak, David F.J.

A photovoltaic module is disclosed. The photovoltaic module has a first side directed toward the sun during normal operation and a second, lower side. The photovoltaic module comprises a perimeter frame and a photovoltaic laminate at least partially enclosed by and supported by the perimeter frame. The photovoltaic laminate comprises a transparent cover layer positioned toward the first side of the photovoltaic module, an upper encapsulant layer beneath and adhering to the cover layer, a plurality of photovoltaic solar cells beneath the upper encapsulant layer, the photovoltaic solar cells electrically interconnected, a lower encapsulant layer beneath the plurality of photovoltaicmore » solar cells, the upper and lower encapsulant layers enclosing the plurality of photovoltaic solar cells, and a homogenous rear environmental protection layer, the rear environmental protection layer adhering to the lower encapsulant layer, the rear environmental protection layer exposed to the ambient environment on the second side of the photovoltaic module.« less

Landscape-scale changes in forest canopy structure across a partially logged tropical peat swamp

NASA Astrophysics Data System (ADS)

Wedeux, B. M. M.; Coomes, D. A.

2015-11-01

Forest canopy structure is strongly influenced by environmental factors and disturbance, and in turn influences key ecosystem processes including productivity, evapotranspiration and habitat availability. In tropical forests increasingly modified by human activities, the interplay between environmental factors and disturbance legacies on forest canopy structure across landscapes is practically unexplored. We used airborne laser scanning (ALS) data to measure the canopy of old-growth and selectively logged peat swamp forest across a peat dome in Central Kalimantan, Indonesia, and quantified how canopy structure metrics varied with peat depth and under logging. Several million canopy gaps in different height cross-sections of the canopy were measured in 100 plots of 1 km2 spanning the peat dome, allowing us to describe canopy structure with seven metrics. Old-growth forest became shorter and had simpler vertical canopy profiles on deeper peat, consistent with previous work linking deep peat to stunted tree growth. Gap size frequency distributions (GSFDs) indicated fewer and smaller canopy gaps on the deeper peat (i.e. the scaling exponent of Pareto functions increased from 1.76 to 3.76 with peat depth). Areas subjected to concessionary logging until 2000, and illegal logging since then, had the same canopy top height as old-growth forest, indicating the persistence of some large trees, but mean canopy height was significantly reduced. With logging, the total area of canopy gaps increased and the GSFD scaling exponent was reduced. Logging effects were most evident on the deepest peat, where nutrient depletion and waterlogged conditions restrain tree growth and recovery. A tight relationship exists between canopy structure and peat depth gradient within the old-growth tropical peat swamp forest. This relationship breaks down after selective logging, with canopy structural recovery, as observed by ALS, modulated by environmental conditions. These findings improve our understanding of tropical peat swamp ecology and provide important insights for managers aiming to restore degraded forests.

Performance enhancement in Sb doped Cu(InGa)Se2 thin film solar cell by e-beam evaporation

NASA Astrophysics Data System (ADS)

Chen, Jieyi; Shen, Honglie; Zhai, Zihao; Li, Yufang; Yi, Yunge

2018-03-01

To investigate the effects of Sb doping on the structural and electrical properties of Cu(InGa)Se2 (CIGS) thin films and solar cells, CIGS thin films, prepared by e-beam evaporation on soda-lime glass, were doped with lower and upper Sb layers in the precursor stacks respectively. Change of structure and introduction of stress were observed in the CIGS thin films with upper Sb layer in stack through XRD and Raman measurement. Both crystalline quality and compactness of CIGS thin films were improved by the doping of upper Sb layer in stack and the CIGS thin film showed an optimal structural property with 20 nm Sb layer. Movement of Fermi level of the surface of CIGS thin film after doping of upper Sb layer in stack and electrons transfer between Cu/Cu+ redox couple and CIGS thin films, which provided probability for the substitution of Sb for Cu sites at the surface of CIGS thin films, were proposed to explain the migration of Cu from the surface to the bulk of CIGS thin films. The larger barrier at the CIGS/CdS interface after doping of upper Sb layer in stack made contribution to the increase of VOC of CIGS solar cells. The efficiency of CIGS solar cell was improved from 3.3% to 7.2% after doping with 20 nm upper Sb. Compared to the CIGS solar cell with lower Sb layer in stack, in which an additional Cu2-xSe phase was found, the CIGS solar cell with upper Sb layer in stack possessed a higher efficiency.

The paleoecology, peat chemistry and carbon storage of a discontinuous permafrost peatland

NASA Astrophysics Data System (ADS)

Talbot, Julie; Pelletier, Nicolas; Olefeldt, David; Turetsky, Merritt; Blodau, Christian; Sonnentag, Oliver; Quinton, William

2017-04-01

Permafrost in peatlands strongly influences ecosystem biogeochemical functioning, vegetation composition and hydrological functions. Permafrost peatlands of northwestern Canada store large amounts of carbon but the peatlands located at the southern margin of the permafrost zone are thawing rapidly. This thaw triggers changes in vegetation, hydrology and peat characteristics, and may affect carbon stocks. We present data from a permafrost plateau to thermokarst bog chronosequence located in the southern portion of the Scotty Creek watershed near Fort Simpson, Northwest Territories, Canada. We assessed changes in plant communities, hydrology, biogeochemistry and permafrost status over 9000 years of peatland development using plant macrofossil, testate amoeba and peat chemical characteristics. Peat accumulation started after the infilling of a lake 8500 cal. yr BP. Minerotrophic peat prevailed at the site until permafrost formed around 5000 cal. yr BP. Permafrost apparently formed three times, although there is spatial variability in the permafrost aggradation - degradation cycles. Permafrost thawed 550 cal. yr BP in the center of the thermokarst bog. Ombrotrophic peat is a fairly recent feature of the peat profiles, only appearing after the most recent permafrost thaw event. Both allogenic (temperature/precipitation/snow cover changes and wildfire) and autogenic (peat accumulation, Sphagnum growth) processes likely influenced permafrost aggradation and thaw. While apparent carbon accumulation rates were lower during present and past permafrost periods than during non-permafrost periods, long term carbon accumulation remained similar between cores with different permafrost period lengths. Deep peat was more decomposed in the thermokarst bog peat profile than in the permafrost plateau profile, highlighting the importance of considering potential deep peat carbon losses to project the fate of thawing permafrost peat carbon stores. Average long-term carbon accumulation derived from the peat cores (n=3, 20.6 ± 1.9 g C m-2 a-1) is in the same range than the contemporary landscape-scale carbon balance measured from eddy covariance at the site ( 15 g C m-2 a-1). While the carbon to nitrogen ratio tends to decrease with peat depth, the carbon to phosphorus ratio tends to increase, perhaps indicating a preferential uptake of phosphorus over nitrogen by plants.

Identification of the Centrifuged Lipoaspirate Fractions Suitable for Postgrafting Survival.

PubMed

Qiu, Lihong; Su, Yingjun; Zhang, Dongliang; Song, Yajuan; Liu, Bei; Yu, Zhou; Guo, Shuzhong; Yi, Chenggang

2016-01-01

The Coleman centrifugation procedure generates fractions with different adipocyte and progenitor cell densities. This study aimed to identify all fractions that are feasible for implantation. Human lipoaspirates were processed by Coleman centrifugation. The centrifugates were divided arbitrarily into upper, middle, and lower layers. Adipocyte viability, morphology, numbers of stromal vascular fraction cells, and adipose-derived mesenchymal stem cells of each layer were determined. The 12-week volume retention of subcutaneously implanted 0.3-ml lipoasperate of each layer was investigated in an athymic mice model. Most damaged adipocytes were located in the upper layers, whereas the intact adipocytes were distributed in the middle and lower layers. A gradient of stromal vascular fraction cell density was formed in the centrifugates. The implant volume retentions of samples from the upper, middle, and lower layers were 33.44 ± 5.9, 55.11 ± 4.4, and 71.2 ± 5.8 percent, respectively. Furthermore, the middle and lower layers contained significantly more adipose-derived stem cells than did the upper layer. The lower layer contains more viable adipocytes and stromal vascular fraction cells leading to the highest implant volume retention, whereas the most impaired cells are distributed in the upper layer, leading to the least volume retention. Although with a lower stromal vascular fraction content, the middle layer has a substantial number of intact adipocytes that are capable of retaining partial adipose tissue volume after implantation, suggesting that the middle layer may be an alternative fat source when large volumes of fat grafts are needed for transplantation.

Fluvial development of the Nete valley during the Late Weichselian and early Holocene: new data from a cross-section south of Kasterlee (NE-Belgium)

NASA Astrophysics Data System (ADS)

Beerten, Koen; Van Nieuland, Jasper; Vandenberghe, Dimitri; Deforce, Koen; Rogiers, Bart

2014-05-01

The Late Quaternary geomorphology and stratigraphy of the fluvial deposits in the Kleine Nete valley is poorly documented, apart from the classic paper by Munaut and Paulissen (1973) on the palaeo-ecology of this river valley. A good description of the fluvial development within this catchment over longer timescales would help to understand palaeohydrological conditions, as it may give insight into changes in river bed elevation and palaeo-channel morphology. As such, existing hydrological models can be tested for conditions that are different than today, by unlocking the palaeohydrological archive. During road construction works, a cross-section through the Kleine Nete alluvium could be observed, directly (tens of meters) south of the present river course and underneath an abandoned channel that is traceable on historical maps and still visible in the landscape today. The river's alluvium is very thin - the sediment thickness usually does not exceed 2-3 m - while the composition is monotonous, either sand or peat with at a thin loamy layer at the top. Different fluvial facies, including horizontally laminated and cross-bedded sands, channel-fill sands, in-situ (?) peat layers, reworked peat mixed with sand, and loamy alluvium were encountered and sampled for grain-size analysis, palynological analysis and optically stimulated luminescence (OSL) dating. The preliminary results show that vertical aggradation took place during the late Pleniglacial (between ca. 20-16 ka) over a large area (probably by a braided river). This aggradation phase was followed by incision and the development of confined channels that subsequently were filled with basal peat and channel sands during the Late Glacial (ca. 15-12 ka) and the early Holocene (ca. 11 ka). The different dimensions of the observed channels (cross-section and river bed elevation), in comparison with those of the present-day river, suggest that large parts of the alluvial plain were experiencing different hydrological conditions during the Late Glacial and early Holocene than today. We conclude that despite the non-continuous nature of the sedimentary archive in the investigated profile, relevant information with respect to the palaeohydrological evolution of the Nete catchment could be obtained. Reference Munaut, A.V., Paulissen, E., 1973. Evolution et paléo-écologie de la vallée de la Petite Nèthe au cours du post-Würm (Belgique). Extrait des Annales de la Société Géologique de Belgique 96, 301-346.

Influence of peat on Fenton oxidation.

PubMed

Huling, S G; Arnold, R G; Sierka, R A; Miller, M R

2001-05-01

A diagnostic probe was used to estimate the activity of Fenton-derived hydroxyl radicals (.OH), reaction kinetics, and oxidation efficiency in batch suspensions comprised of silica sand, crushed goethite (alpha-FeOOH) ore, peat, and H2O2 (0.13 mM). A simple method of kinetic analysis is presented and used to estimate the rate of .OH production (POH) and scavenging term (ks), which were used to establish the influence of organic matter (Pahokee peat) in Fenton systems. POH was greater in the peat-amended systems than in the unamended control, and ks was approximately the same. Any increase in scavenging of .OH that resulted from the addition of peat was insignificant in comparison to radical scavenging by reaction with H2O2. Also, treatment efficiency, defined as the ratio of probe conversion to H2O2 consumption over the same period was greater in the peat-amended system. Results suggest that .OH production is enhanced in the presence of peat by one or more peat-dependent mechanisms. Fe concentration and availability in the peat, reduction of Fe(III) to Fe(II) by the organic matter, and reduction of organic-complexed Fe(III) to Fe(II) are discussed in the context of the Fenton mechanism.

Depth profiling of Pu, 241Am and 137Cs in soils from southern Belarus measured by ICP-MS and alpha and gamma spectrometry.

PubMed

Boulyga, Sergei F; Zoriy, Myroslav; Ketterer, Michael E; Becker, J Sabine

2003-08-01

The depth distribution of plutonium, americium, and 137Cs originating from the 1986 accident at the Chernobyl Nuclear Power Plant (NPP) was investigated in several soil profiles in the vicinity from Belarus. The vertical migration of transuranic elements in soils typical of the 30 km relocation area around Chernobyl NPP was studied using inductively coupled plasma mass spectrometry (ICP-MS), alpha spectrometry, and gamma spectrometry. Transuranic concentrations in upper soil layers ranged from 6 x 10(-12) g g(-1) to 6 x 10(-10) g g(-1) for plutonium and from 1.8 x 10(-13) g g(-1) to 1.6 x 10(-11) g g(-1) for americium. These concentrations correspond to specific activities of (239+240)Pu of 24-2400 Bq kg(-1) and specific activity of 241Am of 23-2000 Bq kg(-1), respectively. Transuranics in turf-podzol soil migrate slowly to the deeper soil layers, thus, 80-95%, of radionuclide inventories were present in the 0-3 cm intervals of turf-podzol soils collected in 1994. In peat-marsh soil migration processes occur more rapidly than in turf-podzol and the maximum concentrations are found beneath the soil surface (down to 3-6 cm). The depth distributions of Pu and Am are essentially identical for a given soil profile. (239+240)Pu/137Cs and 241Am/137Cs activity ratios vary by up to a factor of 5 at some sites while smaller variations in these ratios were observed at a site close to Chernobyl, suggesting that 137Cs is dominantly particle associated close to Chernobyl but volatile species of 137Cs are of relatively greater importance at the distant sites.

The Late-Holocene evolution of the Miseno area (south-western Campi Flegrei) as inferred by stratigraphy, petrochemistry and 40Ar/39Ar geochronology:Chapter 6 in Volcanism in the Campania Plain — Vesuvius, Campi Flegrei and Ignimbrites

USGS Publications Warehouse

Insinga, Donatella; Calvert, Andrew T.; Lanphere, Marvin A.; Morra, Vincenzo; Perrotta, Annamaria; Sacchi, Marco; Scarpati, Claudio; Saburomaru, James; Fedele, Lorenzo

2006-01-01

This study on terrestrial and marine successions increases the understanding of the Late-Holocene volcanological and stratigraphical evolution of the south-western part of Campi Flegrei caldera.Stratigraphic data derived from field studies of two major tuff vents located along the coastal zone, namely Porto Miseno and Capo Miseno, clearly indicate that the Porto Miseno tuff ring slightly predates the Capo Miseno tuff cone. 40Ar/39Ar step-heating experiments, carried out on fresh sanidine separates from pumice samples, yielded a plateau age of 5090±140 yr BP for Capo Miseno and 6490±510 yr BP for Porto Miseno vent, thus confirming field observations.The volcanoclastic input derived from this recent and intense eruptive activity played a major role in the inner-shelf stratigraphic evolution of the Porto Miseno Bay deposits that have been drilled up to 40 m depth off the crater rim. The cored succession is characterised by transgressive marine deposits (mostly volcanic sand) with two intercalated peat layers (t1 and t2), dated at 3560±40 yr BP and 7815±55 yr BP (14C), respectively, interbedded with a 1–5 m thick pumice layer (tephra C). Peat layers have been chronostratigraphically correlated with two widespread paleosols onland while petrochemical analyses allowed us to correlate tephra C with the Capo Miseno tuff cone deposits.The results presented in this study imply a Late-Holocene volcanic activity that is also well preserved in the marine record in this sector of the caldera where a new chronostratigraphic reconstruction of the eruptive events is required in order to better evaluate the hazard assessment of the area.

The Impact of Climate Change on Microbial Communities and Carbon Cycling in High Arctic Permafrost Soil from Spitsbergen, Northern Norway

NASA Astrophysics Data System (ADS)

de Leon, K. C.; Schwery, D.; Yoshikawa, K.; Christiansen, H. H.; Pearce, D.

2014-12-01

Permafrost-affected soils are among the most fragile ecosystems in which current microbial controls on organic matter decomposition are changing as a result of climate change. Warmer conditions in the high Arctic will lead to a deepening of the seasonal active layer of permafrost, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. The viable and non-viable fractions of the microbial community in a permafrost soil from Adventdalen, Spitsbergen, Norway were subjected to a comprehensive investigation using culture-dependent and culture-independent methods. Molecular analyses using FISH (with CTC-DAPI) and amplified rDNA restriction analysis (ARDRA) on a 257cm deep core, revealed the presence of all major microbial soil groups, with the active layer having more viable cells, and a higher microbial community diversity. Carbon dioxide (CO2) and methane (CH4) flux measurements were performed to show the amount of C stored in the sample. We demonstrated that the microbial community composition from the soil in the center of the core was most likely influenced by small scale variations in environmental conditions. Community structure showed distinct shift of presence of bacterial groups along the vertical temperature gradient profile and microbial counts and diversity was found to be highest in the surface layers, decreasing with depth. It was observed that soil properties driving microbial diversity and functional potential varied across the permafrost table. Data on the variability of CO2 and CH4 distribution described in peat structure heterogeneity are important for modeling emissions on a larger scale. Furthermore, linking microbial biomass to gas distribution may elucidate the cause of peak CO2 and CH4 and their changes in relation to environmental change and peat composition.

Freshwater and Saline Loads of Dissolved Inorganic Nitrogen to Hood Canal and Lynch Cove, Western Washington

USGS Publications Warehouse

Paulson, Anthony J.; Konrad, Christopher P.; Frans, Lonna M.; Noble, Marlene; Kendall, Carol; Josberger, Edward G.; Huffman, Raegan L.; Olsen, Theresa D.

2006-01-01

Hood Canal is a long (110 kilometers), deep (175 meters) and narrow (2 to 4 kilometers wide) fjord of Puget Sound in western Washington. The stratification of a less dense, fresh upper layer of the water column causes the cold, saltier lower layer of the water column to be isolated from the atmosphere in the late summer and autumn, which limits reaeration of the lower layer. In the upper layer of Hood Canal, the production of organic matter that settles and consumes dissolved oxygen in the lower layer appears to be limited by the load of dissolved inorganic nitrogen (DIN): nitrate, nitrite, and ammonia. Freshwater and saline loads of DIN to Hood Canal were estimated from available historical data. The freshwater load of DIN to the upper layer of Hood Canal, which could be taken up by phytoplankton, came mostly from surface and ground water from subbasins, which accounts for 92 percent of total load of DIN to the upper layer of Hood Canal. Although DIN in rain falling on land surfaces amounts to about one-half of the DIN entering Hood Canal from subbasins, rain falling directly on the surface of marine waters contributed only 4 percent of the load to the upper layer. Point-source discharges and subsurface flow from shallow shoreline septic systems contributed less than 4 percent of the DIN load to the upper layer. DIN in saline water flowing over the sill into Hood Canal from Admiralty Inlet was at least 17 times the total load to the upper layer of Hood Canal. In September and October 2004, field data were collected to estimate DIN loads to Lynch Cove - the most inland marine waters of Hood Canal that routinely contain low dissolved-oxygen waters. Based on measured streamflow and DIN concentrations, surface discharge was estimated to have contributed about one-fourth of DIN loads to the upper layer of Lynch Cove. Ground-water flow from subbasins was estimated to have contributed about one-half of total DIN loads to the upper layer. In autumn 2004, the relative contribution of DIN from shallow shoreline septic systems to the upper layer was higher in Lynch Cove (23 percent) than in the entire Hood Canal. Net transport of DIN into Lynch Cove by marine currents was measured during August and October 2004-a time of high biological productivity. The net transport of lower-layer water into Lynch Cove was significantly diminished relative to the flow entering Hood Canal at its entrance. Even though the net transport of saline water into the lower layer of Lynch Cove was only 119 cubic meters per second, estuarine currents between 33 and 47 m were estimated to have carried more than 35 times the total freshwater load of DIN to the upper layer from surface and ground water, shallow shoreline septic systems, and direct atmospheric rainfall. The subsurface maximums in measured turbidity, chlorophyll a, particulate organic carbon, and particulate organic nitrogen strongly suggest that the upward mixing of nitrate-rich deeper water is a limiting factor in supplying DIN to the upper layer that enhances marine productivity in Lynch Cove. The presence of phosphate in the upper layer in the absence of dissolved inorganic nitrogen also suggests that the biological productivity that leads to low dissolved-oxygen concentrations in the lower layer of Lynch Cove is limited by the supply of nitrogen rather than by phosphate loads. Although the near-shore zones of the shallow parts of Lynch Cove were sampled, a biogeochemical signal from terrestrial nitrogen was not found. Reversals in the normal estuarine circulation suggest that if the relative importance of the DIN load of freshwater terrestrial and atmospheric sources and the DIN load from transport of saline water by the estuarine circulation in controlling dissolved-oxygen concentrations in Lynch Cove is to be better understood, then the physical forces driving Hood Canal circulation must be better defined.

Airborne Petcoke Dust is a Major Source of Polycyclic Aromatic Hydrocarbons in the Athabasca Oil Sands Region.

PubMed

Zhang, Yifeng; Shotyk, William; Zaccone, Claudio; Noernberg, Tommy; Pelletier, Rick; Bicalho, Beatriz; Froese, Duane G; Davies, Lauren; Martin, Jonathan W

2016-02-16

Oil sands mining has been linked to increasing atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in the Athabasca oil sands region (AOSR), but known sources cannot explain the quantity of PAHs in environmental samples. PAHs were measured in living Sphagnum moss (24 sites, n = 68), in sectioned peat cores (4 sites, n = 161), and snow (7 sites, n = 19) from ombrotrophic bogs in the AOSR. Prospective source samples were also analyzed, including petroleum coke (petcoke, from both delayed and fluid coking), fine tailings, oil sands ore, and naturally exposed bitumen. Average PAH concentrations in near-field moss (199 ng/g, n = 11) were significantly higher (p = 0.035) than in far-field moss (118 ng/g, n = 13), and increasing temporal trends were detected in three peat cores collected closest to industrial activity. A chemical mass-balance model estimated that delayed petcoke was the major source of PAHs to living moss, and among three peat core the contribution to PAHs from delayed petcoke increased over time, accounting for 45-95% of PAHs in contemporary layers. Petcoke was also estimated to be a major source of vanadium, nickel, and molybdenum. Scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed large petcoke particles (>10 μm) in snow at near-field sites. Petcoke dust has not previously been considered in environmental impact assessments of oil sands upgrading, and improved dust control from growing stockpiles may mitigate future risks.

Effect of soil type and moisture availability on the foraging behavior of the Formosan subterranean termite (Isoptera: Rhinotermitidae).

PubMed

Cornelius, Mary L; Osbrink, Weste L A

2010-06-01

This study examined the influence of soil type and moisture availability on termite foraging behavior. Physical properties of the soil affected both tunneling behavior and shelter tube construction. Termites tunneled through sand faster than top soil and clay. In containers with top soil and clay, termites built shelter tubes on the sides of the containers. In containers with sand, termites built shelter tubes directly into the air and covered the sides of the container with a layer of sand. The interaction of soil type and moisture availability affected termite movement, feeding, and survival. In assays with moist soils, termites were more likely to aggregate in top soil over potting soil and peat moss. However, termites were more likely to move into containers with dry peat moss and potting soil than containers with dry sand and clay. Termites were also significantly more likely to move into containers with dry potting soil than dry top soil. In the assay with dry soils, termite mortality was high even though termites were able to travel freely between moist sand and dry soil, possibly due to desiccation caused by contact with dry soil. Evaporation from potting soil and peat moss resulted in significant mortality, whereas termites were able to retain enough moisture in top soil, sand, and clay to survive for 25 d. The interaction of soil type and moisture availability influences the distribution of foraging termites in microhabitats.

Impact of fire on macropore flow and the hydraulic conductivity of near-surface blanket peat

NASA Astrophysics Data System (ADS)

Holden, Joseph; Wearing, Catherine; Palmer, Sheila; Jackson, Benjamin; Johnston, Kerrylyn; Brown, Lee

2013-04-01

Peatlands can be subject to wildfire or deliberate burning in many locations. Wildfires are known to impact soil properties and runoff production in most soil types but relatively little work has been conducted on peatlands. Furthermore in large parts of the UK uplands prescribed vegetation burning on peat has taken place at regular intervals (e.g. every 8-25 years) on patches of around 300-900 sq. metres over the past century to support increased grouse populations for sport shooting. However, there have been few studies on how these prescribed fires influence near-surface hydrology. It is known that macropores transport a large proportion of flow in near-surface peat layers and we investigated their role in flow transport for fire sites using tension infiltrometers. Measurements were performed, at replicated hillslope positions to control for slope position effects, on unburnt peat (U) and where prescribed burning had taken place two years (P2), four years (P4) and >15 years (P15+) prior to sampling. For the prescribed burning plots, vegetation burning had also occurred at around a 15-20 year interval for most of the past century. We also sampled a nearby wildfire site (W) with the same sampling design where wildfire had occurred four months prior to sampling. Both the contribution of macropore flow to overall infiltration, and the saturated hydraulic conductivity, were significantly lower in the recently burnt sites (W, P2, P4), compared to P15+ and U. There was no significant difference in macropore flow contributions, effective macroporosity and saturated hydraulic conductivity between P15+ and U. The results suggest fire influences the near-surface hydrological functioning of peatlands but that 'recovery' for some hydrological processes to prescribed vegetation burning may be possible within two decades if there are no further fires.

The production of black carbon during managed burning of UK peatlands: could managed burning of peatlands lead to enhanced carbon storage?

NASA Astrophysics Data System (ADS)

Clay, G.; Worrall, F.

2008-12-01

Peatlands are the UK's largest single terrestrial carbon store with carbon stored in UK peatlands than in forests of Britain and France combined. Unlike most northern peatlands in the peat soils of the UK are heavily managed for recreation and agriculture and due to their proximity to major centres of population are under more anthropogenic pressure than most peatlands. A typical management strategy on UK upland peats is the use of managed fire to restrict vegetation. Fires are used upon a 10-25 year rotation and are described as "cool" as they are designed to remove the crown of the vegetation without scorching the litter layer or the underlying soil. In this case the fire destroys primary productivity and limits litter production but produces char. Char is a low volume, highly refractory, high carbon content product while litter is a high volume, decomposable, lower carbon content product. Therefore, the question is if there are fire conditions under which the production of char causes more carbon to be stored in the peat than would have been stored if no fire management had been employed. This study combines field studies of recent managed burns and wildfires along with detailed vegetation studies from a long term monitoring site in order to assess litter, biomass and black carbon production. In the laboratory experimental burns were undertaken in order to assess the amount and controls upon char production and the carbon content of that char. Results of field and laboratory observations are used to model carbon accumulation under a series of fire management scenarios and the modelling shows that cools burns at long rotations could lead to higher carbon storage than if no fire had occurred, further in several cases more carbon accumulation occurred even if less depth of peat was generated.

Factors controlling peat chemistry and vegetation composition in Sudbury peatlands after 30 years of pollution emission reductions.

PubMed

Barrett, Sophie E; Watmough, Shaun A

2015-11-01

The objective of this research was to assess factors controlling peat and plant chemistry, and vegetation composition in 18 peatlands surrounding Sudbury after more than 30 years of large (>95%) pollution emission reductions. Sites closer to the main Copper Cliff smelter had more humified peat and the surface horizons were greatly enriched in copper (Cu) and nickel (Ni). Copper and Ni concentrations in peat were significantly correlated with that in the plant tissue of Chamaedaphne calyculata. The pH of peat was the strongest determining factor for species richness, diversity, and community composition, although percent vascular plant cover was strongly negatively correlated with surface Cu and Ni concentrations in peat. Sphagnum frequency was also negatively related to peat Cu and Ni concentrations indicating sites close to Copper Cliff smelter remain adversely impacted by industrial activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Excavating and loading equipment for peat mining

NASA Astrophysics Data System (ADS)

Mikhailov, A. V.; Zhigulskaya, A. I.; Yakonovskaya, T. B.

2017-10-01

Recently, the issues of sustainable development of Russian regions, related to ensuring energy security, are more urgent than ever. To achieve sustainable development, an integrated approach to the use of local natural resources is needed. Practically in all north regions of the Russian Federation, peat as a local natural resource is widespread, which has a practical application in the area of housing services. The paper presents the evaluation of technologies for open-pit peat mining, as well as analysis of technological equipment for peat production. Special attention is paid to a question of peat materials excavating and loading. The problem of equipment selection in a peat surface mine is complex. Many features, restrictions and criteria need to be considered. Use of low and ultra-low ground pressure excavators and low ground pressure front-end loaders with full-range tires to provide the necessary floatation in the peat bog environment is offered.

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

NASA Astrophysics Data System (ADS)

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

2002-07-01

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

Impacts of ditch blocking on peatland hydrology - the benefits of long-term monitoring

NASA Astrophysics Data System (ADS)

Holden, Joseph; Green, Sophie; Baird, Andy; Chapman, Pippa; Evans, Chris; Grayson, Richard

2016-04-01

A long-term field trial was conducted on a blanket peatland in North Wales. Twelve ditches were studied. After an initial monitoring period, eight of the ditches had peat dams installed a few metres apart along their entire length (dammed), four of these ditches were also partially infilled through bank reprofiling (reprofiled). Four ditches were left open with no dams or reprofiling (open). These 12 ditches and the surrounding peat were then monitored for a further 4 years. The effect of ditch blocking on local water tables was spatially highly variable but small overall (of the order of 2-3 cm) because the site, despite having ditches, already had relatively shallow water tables (medians within the upper 10 cm of the peat profile). An initial five-fold reduction in discharge occurred in ditches that had been dammed or reprofiled. However, there was evidence of a slow change over time in ditch flow at the site in subsequent years, with the overall volume of water leaving the dammed or reprofiled ditch weirs increasing per unit of rainfall to around twice that which occurred in the first year after the restoration. These changes were not observed in the open ditches. There was therefore clear evidence of the benefits of long-term monitoring as hydrological impacts in the first year after ditch blocking were very different from those in later years as the site conditions gradually changed. The additional water that flowed in later periods of the study from the blocked ditch catchments occurred in the form of a more continuously-flowing baseflow with fewer dry periods. The cause of this increase was related to changes in subsurface flow pathways in the peat in the aftermath of re-wetting. We show that these subsurface pathways mean that even in sloping blanket peatlands, the catchment areas for peatland ditches may be very different from that expressed by surface topography alone. Therefore, peatland studies that have estimated aerially-weighted water or carbon fluxes from one or two open or blocked ditches and where such data have also been used in upscaling estimates, need to be treated with caution.

[Research on output and quality of Panax notoginseng and annual change characteristics of N, P and K nutrients of planting soil under stereo-cultivation].

PubMed

Huang, Chun-mei; Cui, Xiu-ming; Lan, Lei; Chen, Wei-dong; Wang, Cheng-xiao; Yang, Xiao-yan; Lu, Da-hui; Yang, Ye

2015-08-01

The output and agronomic characters of 3-year-old Panax notoginseng cultured under stereo structure (upper, middle and down layers) were investigated, and the annual change of N, P and K of its planting soil were also studied. Results showed that, compared with field cultured Panax notoginseng, growth vigour and output of stereo-cultivation were significantly lower. But the total production of the 3 layers was 1.6 times of field. The growth vigor and production of P. notoginseng was in the order of upper layer > middle layer > down layer. The content of ginsenoside in rhizome, root tuber and hair root of P. notoginseng was in the order of upper layer > field > middle layer > down layer. Organic matter content and pH of stereo-cultivation soil decreased with the prolonging of planting time, which with the same trend of yield. Organic matter content of stereo-cultivation soil was significantly higher than field, but the pH was significantly lower. Contents of total and available N, P and K in stereo-cultivation soil and field decreased with the prolonging of planting time. The content of N and P were in the order of upper layer > middle layer > yield > down layer, the content of K was in the order of upper layer > middle layer > down layer > yield. Compared with field, the proportion of N and P in the organ of underground (rhizome, root tuber and hair root) of upper layer were increased, while decreased in middle and down layers. Proportion of K in underground decreased significantly of the 3 layers. In conclusion, the agronomic characters and production of stereo-cultivation were significantly lower than that of yield. But the total production of the 3 layers were significantly higher than field of unit area. And the aim of improving land utilization efficiency was achieved. Nutritions in the soil of stereo-cultivation were enough to support the development of P. notoginseng, which was not the cause of weak growth and low production. The absorbing ability of P. notoginseng to N, P and K nutrients was decreased by stereo-cultivation mode. So, improve the growth vigour of P. notoginseng from the perspective of adjusting the stereo-cultivation mode so as to improve the nutrient absorption capacity is the future direction.

Peat Processing

NASA Technical Reports Server (NTRS)

1986-01-01

Humics, Inc. already had patented their process for separating wet peat into components and processing it when they consulted NERAC regarding possible applications. The NERAC search revealed numerous uses for humic acid extracted from peat. The product improves seed germination, stimulates root development, and improves crop yields. There are also potential applications in sewage disposal and horticultural peat, etc.

Growing reforestation conifer stock: Utilizing peat/sawdust medium

Treesearch

Janice K. Schaefer

2009-01-01

Western Forest Systems, Incorporated (WFS) (Lewiston, ID) has been utilizing a peat/sawdust blended mix as our growing medium for the past 10 years. Our decision to change from a peat/vermiculite blend to a peat/Douglas-fir (Pseudotsuga menziesii) sawdust blend involved worker health and safety issues, seedling culture, seedling production, and...

Spatial variation of peat soil properties in the oil-producing region of northeastern Sakhalin

NASA Astrophysics Data System (ADS)

Lipatov, D. N.; Shcheglov, A. I.; Manakhov, D. V.; Zavgorodnyaya, Yu. A.; Rozanova, M. S.; Brekhov, P. T.

2017-07-01

Morphology and properties of medium-deep oligotrophic peat, oligotrophic peat gley, pyrogenic oligotrophic peat gley, and peat gley soils on subshrub-cotton grass-sphagnum bogs and in swampy larch forests of northeastern Sakhalin have been studied. Variation in the thickness and reserves of litters in the studied bog and forest biogeocenoses has been analyzed. The profile distribution and spatial variability of moisture, density, ash, and pHKCl in separate groups of peat soils have been described. The content and spatial variability of petroleum hydrocarbons have been considered in relation to the accumulation of natural bitumoids by peat soils and the technogenic pressing in the oil-producing region. Variation of each parameter at different distances (10, 50, and 1000 m) has been estimated using a hierarchical sampling scheme. The spatial conjugation of soil parameters has been studied by factor analysis using the principal components method and Spearman correlation coefficients. Regression equations have been proposed to describe relationships of ash content with soil density and content of petroleum hydrocarbons in peat horizons.

Peat resources of Maine. Volume 2. Penobscot County

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron, C.C.; Mullen, M.K.; Lepage, C.A.

1984-01-01

In July 1979, the Maine Office of Energy Resources, in conjunction with the Maine Geological Survey, began the Maine Peat Resource Evaluation Program. The Program, which was funded by the US Department of Energy (DOE), was undertaken to determine the amount and location of fuel-grade peat in Maine. Two hundred thirty-three areas containing peat deposits were evaluated under the Program. A total of 47 deposits covering 21,666 acres and containing 40,923,000 short tons (dry weight) of peat in Penobscot County have been evaluated under the Maine Peat Resource Evaluation Program. These deposits range in size from 35 to 3301 acresmore » and in estimated resources from 45,000 to 6,994,000 short tons. Maps of individual deposits showing the distribution and depth of peat, core sites, and the surficial geology of the area adjacent to the deposits are shown in Figures 4 to 46. Cores showing the vertical distribution of peat and sediment as well as sample locations, and the results of laboratory analyses are also included. 22 references, 46 figures, 3 tables.« less

Investigation of smoldering combustion propagation of dried peat

NASA Astrophysics Data System (ADS)

Palamba, Pither; Ramadhan, M. L.; Imran, F. A.; Kosasih, E. A.; Nugroho, Y. S.

2017-03-01

Smoldering is a form of combustion characterised by flameless burning of porous materials. Smoldering combustion of porous and organic soil such as peat, is considered as a major contributor to haze problem during wildland fires in Sumatra and Kalimantan, Indonesia. With almost half of tropical peatland worldwide, and vast area that resulted in its rich agricultural diversity, Indonesia possessed many variants of peat throughout the region. Thus, further highlighting the importance of characterizing the thermal properties of different varieties of peats for further analysis. An experimental test method was built to analyse the differences of varying peats from different parts of Indonesia, regarding its smoldering combustion propagation. In this case, peat from Papua and South Sumatera were analysed. A cylindrical wire meshed container of 190 cm3 in volume, was filled with dried peat. The temperature data and mass loss during the smoldering combustion was gathered using thermocouples and a DAQ system. After the experimental apparatus was set, a smoldering combustion of the dried peats was initiated at the top of the container using an electric heater. The results of the experiment showed a smoldering temperature of about 600°C and with a smoldering propagation rate of about 4.50 to 4.75 cm/h for both peat samples.

A Database and Synthesis of Northern Peatland Soil Properties and Holocene Carbon and Nitrogen Accumulation

NASA Technical Reports Server (NTRS)

Loisel, Julie; Yu, Zicheng; Beilman, David W.; Camill, Philip; Alm, Jukka; Amesbury, Matthew J.; Anderson, David; Andersson, Sofia; Bochicchio, Christopher; Barber, Keith;

Physicochemical properties of hydrothermally treated peat fuel obtained from Mempawah-West Kalimantan: influence of hydrophilicity index on carbon aromaticity and combustibility

NASA Astrophysics Data System (ADS)

Mursito, Anggoro Tri; Hirajima, T.; Listiyowati, L. N.

2018-02-01

Mempawah peat of West Kalimantan was selected as raw material for studying the physicochemical properties of peat fuel products and their characteristic in the hydrothermal upgrading process at a temperature range of 150°C to 380°C at an average heating rate of 6.6°C/min for 30 minutes. The 13C NMR spectra revealed changes in the effect of temperature on carbon aromaticity of raw peat and peat fuel products which were in 0.39 to 0.63 as the temperature increased. Other phenomenon occurring during the experiment was hydrophilicity index of peat fuel surface decreases of about 1.7 and 1.4 with increased treatment temperature. We also found that hydrothermal upgrading also affected the combustion properties of peat fuel products. Ignition temperature of raw peat and solid products were at 175°C and between 188°C to 285°C respectively. Temperature at the maximum combustion rate of raw peat and solid products was at 460°C, and between 477°C to 509°C were suggested to the increasing of reactivity of solid products respectively. Here, we discussed several phenomenon of the peat fuel product during hydrothermal process with a respect to the change in the physicochemical properties as determined by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric and Differential Thermal Analysis (TG-DTA) analyses, 13C NMR and also other supporting analytical equipment.

Electron transfer properties of peat organic matter: from electrochemical analysis to redox processes in peatlands

NASA Astrophysics Data System (ADS)

Sander, Michael; Getzinger, Gordon; Walpen, Nicolas

2017-04-01

Peat organic matter contains redox-active functional groups that can accept and/or donate electrons from and to biotic and abiotic reaction partners present in peatlands. Several studies have provided evidence that electron accepting quinone moieties in the peat organic matter may act as terminal electron acceptors for anaerobic microbial respiration. This respiration pathway may competitively suppress methanogenesis and thereby lead to excess carbon dioxide to methane formation in peatlands. Electron donating phenolic moieties in peat organic matter have long been considered to inhibit microbial and enzymatic activities in peatlands, thereby contributing to carbon stabilization and accumulation in these systems. Phenols are expected to be comparatively stable in anoxic parts of the peats as phenoloxidases, a class of enzymes capable of oxidatively degrading phenols, require molecular oxygen as co-substrate. Despite the general recognition of the importance of redox-active moieties in peat organic matter, the abundance, redox properties and reactivities of these moieties remain poorly studied and understood, in large part due to analytical challenges. This contribution will, in a first part, summarize recent advances in our research group on the analytical chemistry of redox-active moieties in peat organic matter. We will show how mediated electrochemical analysis can be used to quantify the capacities of electron accepting and donating moieties in both dissolved and particulate peat organic matter. We will link these capacities to the physicochemical properties of peat organic matter and provide evidence for quinones and phenols as major electron accepting and donating moieties, respectively. The second part of this contribution will highlight how these electroanalytical techniques can be utilized to advance a more fundamental understanding of electron transfer processes involving peat organic matter. These processes include the redox cycling (i.e., repeated reduction and re-oxidation) of peat organic matter under alternating anoxic-oxic conditions as well as the oxidation of phenolic moieties in peat organic matter by phenol oxidases in the presence of molecular oxygen. Overall, this contribution will attempt to link molecular-level insights into the redox properties of peat organic matter to larger scale redox processes that are important to carbon cycling in peatlands.

Sulfur variability and petrology of the Lower Block Coal Member (Pennsylvanian) in Southwest Indiana

USGS Publications Warehouse

Padgett, P.L.; Rimmer, S.M.; Ferm, J.C.; Hower, J.C.; Eble, C.F.; Mastalerz, Maria

1999-01-01

The Lower Block Coal Member (Pennsylvanian-Atokan, Westphalian C) is an economic low-to medium-sulfur, low-ash coal resource in the Illinois Basin. Sulfur content is generally low (averaging 1.0%) in the study area, but varies over short distances. Higher sulfur areas occur as isolated pods and epigenetic pyrite increases significantly in the upper third of the selected columns in higher sulfur areas. Sulfur variations cannot be predicted by typical geologic characteristics such as roof lithology, seam thickness, or seam elevation. Petrographic analysis shows that pyrite is generally associated with brighter microlithotypes, except in higher sulfur areas where infilling pyrite forms are associated with inertite. Higher sulfur areas reflect the water chemistry of the paleomire during and shortly after peat accumulation. Locally, abundant pyrofusinite provided additional pore space for pyrite precipitation.The Lower Block Coal Member (Pennsylvanian-Atokan, Westphalian C) is an economic low- to medium-sulfur, low-ash coal resource in the Illinois Basin. Sulfur content is generally low (averaging 1.0%) in the study area, but varies over short distances. Higher sulfur areas occur as isolated pods and epigenetic pyrite increases significantly in the upper third of the selected columns in higher sulfur areas. Sulfur variations cannot be predicted by typical geologic characteristics such as roof lithology, seam thickness, or seam elevation. Petrographic analysis shows that pyrite is generally associated with brighter microlithotypes, except in higher sulfur areas where infilling pyrite forms are associated with inertite. Higher sulfur areas reflect the water chemistry of the paleomire during and shortly after peat accumulation. Locally, abundant pyrofusinite provided additional pore space for pyrite precipitation.

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

PubMed

Drobnik, Jacek; Stebel, Adam

2017-09-14

Sphagnum mosses and peat could have been utilized as wound dressings for centuries, however reliable data on this subject are ambiguous; sometimes even no distinction between peat moss (Sphagnum spp.) and peat is made or these terms become confused. The first scientific account on surgical use of peat comes from 1882: a peat digger who successfully, by himself and in the way unknown to the then medicine, cured an open fracture of his forearm with peat. The peat, and very soon the peat moss itself (which is the major constituent of peat) drew attention of the 19th-century surgeons. We search for reliable information on: (1) inspirations for Sphagnum usage for medical purposes and its beginnings in the 19th century, (2) substances or products named sphagnol and their connections with (1); (3) on the origin of this name, (4) and on the occurrence of this name in medical sources. We have identified and studied published sources on the uses of peat-based and Sphagnum-based preparations and products of any processing level (including herbal stock, distillate, isolated pure or impure active principle, or a mixture of such) in surgery, pharmacy or cosmetics. A special attention was paid to the name sphagnol, which appeared many a time, in more than one context since 1899. Source publications were critically analysed from the taxonomical, pharmacognostical and ethnopharmacological points of view. Gathered data were cross-checked with the modern knowledge of the biologically active principles of Sphagnum and the prospects of their medical use. The application of peat in surgery started 1882. The use of peat moss as dressings was developed in the 1880's. It returned to surgical practice during WW1. The name sphagnol has two meanings: (1) A chemical substance isolated from the cell walls of Sphagnum mosses in 1899. A post-1950 research showed it to be a mixture of phenols dominated by sphagnum acid. (2) A product of dry distillation of peat contains solid and liquid fractions and was applied in skin diseases due to antiseptic properties. It was added to ointments and medicated soaps manufactured up to the late 1960's. Today none of these two sphagnols is in use. Surgical application of peat had an ethnopharmacological origin: a case of wound treatment with peat as a remedy rather than a dressing (1880, published 1882) shortly shifted the surgeons' attention to peat moss as an absorptive dressing. The 1880's tests of antiseptic properties of peat and peat moss failed, the sterilization methods overrode the physiological effects of Sphagnum dressings. Sphagnan, a polysaccharide from Sphagnum cell walls, discovered 1983, inhibits microbial growth, tans the collagen and removes ammonia from microbial environments. Portions of raw peat could be sterile. The isolation of sphagnol (1899) from Sphagnum cell walls was not inspired by old surgery. Main component of sphagnol, the sphagnic acid, was used clinically during WW2, but was proved a weak antimicrobial agent. A homonymous name sphagnol appeared independently for a product of dry distillation of peat, introduced commercially probably about 1899, too, which gave rise to confusions: a) the commercial, "distilled" sphagnol was not the crystalline principle of Sphagnum cell walls. 2) the "distilled" sphagnol was hardly defined technologically or pharmacologically, never standardized in terms of the substrate (a variety of peat rather than Sphagnum herb) and the production process. This sphagnol, resembling pitch or tar, was an additive to medicated soaps and ointments for skin treatment and care. It must have been a low-scale product although advertised worldwide. Neither sphagnum acid nor sphagnan are used medicinally today. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

A Few Issues on the Peat Research in the Altai Mountains

NASA Astrophysics Data System (ADS)

Inisheva, Lydia I.; Larina, Galina; Shurova, Maya

2010-05-01

At the present time we carry out complex research of marsh ecosystems in various areas of Gorny Altai to reveal the perspective deposits of peat in the Altai Mountains with the purpose of its use in the medical and recreational spheres. The peat deposits of the Northeastern Altai, Central Altai, and Southeastern Altai are surveyed; the selective chemical analysis of peat and marsh waters is carried out. The group structure of organic substance of various samples of peat is investigated by the method of Institutes of Peat. The toxic metals of Cd, Pb, Hg, Cu, Zn, and As were defined by the method of stripping voltammetry. The region of the Altai Mountains is characterized by the contrastive distribution of some heavy metals and arsenic in a soil cover. This is caused by a variety of petrography and granulometry of soil forming material, and also by a landscape and geochemical situation in the system of vertical zoning. The sources of natural accumulation of heavy metals in the ground might be the deposits of polymetals. In this connection the content of the specified toxic elements in the peat under research has been identified. The peat of the Turochak deposit is characterized by a significant ash content - up to 41,9%; the increased ash content is typical of the Kutyush deposit: from 6,1% up to 19, %. The peat of the Northeastern Altai is referred to non-bitumunous: the content of bitumen makes up less than 5%. In comparison with the European peat the peat under study of the transitive and lowland type is characterized by the significant content of easy hydrolysable substances in the amount of 24,8-41,1%. The amount of the non-hydrolysable rest makes up around 4,3 - 7,4 %. The total content of fulvic acids is less than the content of humic acids by 2,9 - 5,8 times. The high content of humic acids which can reach up to 58 % is characteristic of certain deposits. Humic acids extracted from the peat are characterized, as a rule, by similar IR-spectra. The distinctions are shown in an unequal intensity of characteristic absorption bands, in their spreading and some shifts. It is revealed that humic acids of peat with the increase in a degree of decomposition are exposed to transformation; therefore the increase in their structure of functional groups is observed. As a result of the research which was carried out the following elements among heavy metals in the lowland peat of the Altai Mountains are revealed: Cd (2,7 - 30)> Hg (0,67)> Zn (0,22) ~Pb (0,21)> Cu (0,13)> As (0,03). The degree of mobility of chemical elements in the peat varies within the limits of 1,3 - 36%. According to the degree of their mobility these elements form the following line: Zn (36 %)> Pb (18,1 %)> Cd (9,6 %)> Cu (1,3 %). The content and the character of distribution of the heavy metals under study and arsenic in the peat of the Altai Mountains have their unique features in comparison with the same valley analogues. The mountain peat of the Central Altai contains much less Hg than the West Siberian one: 0,078 mg/g and 0,69 mg/g accordingly. Cd represents itself as the concentrator in the lowland peat of the Northeastern and Central Altai, its content is actually the same and makes up approximately 0,3 mg/kg. The lowland Altai and West Siberian peat has the same amount of Pb: 4-5 mg/kg; they have smaller amounts of Zn and Cu in comparison with the European and West Siberian peat. The revealed features of distribution of some toxic metals are the display of specificity of peat genesis in the conditions of a mountain relief. The complex of the data received by us allows to consider the peat of the Altai Mountains as a non-polluting raw source concerning the amount of some natural toxic substances. The possible perspective directions of practical application of the mountain peat can be medicine, veterinary science, and agriculture.

Uplifting of palsa peatlands by permafrost identified by stable isotope depth profiles

NASA Astrophysics Data System (ADS)

Krüger, Jan Paul; Conen, Franz; Leifeld, Jens; Alewell, Christine

2015-04-01

Natural abundances of stable isotopes are a widespread tool to investigate biogeochemical processes in soils. Palsas are peatlands with an ice core and are common in the discontinuous permafrost region. Elevated parts of palsa peatlands, called hummocks, were uplifted by permafrost out of the influence of groundwater. Here we used the combination of δ15N values and C/N ratio along depth profiles to identify perturbation of these soils. In the years 2009 and 2012 we took in total 14 peat cores from hummocks in two palsa peatlands near Abisko, northern Sweden. Peat samples were analysed in 2 to 4 cm layers for stable isotope ratios and concentrations of C and N. The uplifting of the hummocks by permafrost could be detected by stable isotope depth patterns with the highest δ15N value at permafrost onset, a so-called turning point. Regression analyses indicated in 11 of 14 peat cores increasing δ15N values above and decreasing values below the turning point. This is in accordance with the depth patterns of δ13C values and C/N ratios in these palsa peatlands. Onset of permafrost aggradation identified by the highest δ15N value in the profile and calculated from peat accumulation rates show ages ranging from 80 to 545 years and indicate a mean (±SD) peat age at the turning points of 242 (±66) years for Stordalen and 365 (±53) years for Storflaket peatland. The mean peat ages at turning points are within the period of the Little Ice Age. Furthermore, we tested if the disturbance, in this case the uplifting of the peat material, can be displayed in the relation of δ15N and C/N ratio following the concept of Conen et al. (2013). In unperturbed sites soil δ15N values cover a relatively narrow range at any particular C/N ratio. Changes in N cycling, i.e. N loss or gain, results in the loss or gain of 15N depleted forms. This leads to larger or smaller δ15N values than usual at the observed C/N ratio. All, except one, turning point show a perturbation in the depth profile, with most of the adjacent sampling points also indicating perturbation. This perturbation shows the changes in N cycling, in this case N loss, from these depths due to permafrost aggradation. Deeper parts of some profiles at Stordalen peatland indicate with the same approach an N gain, maybe due to lateral N input to these nutrient poor ecosystems. Most of the uppermost samples in the δ15N depth profiles show no perturbation, potentially due to the adaptation of these soils to the new conditions. Both stable isotope (δ15N and δ13C) depth profiles are suitable to detect palsa uplifting by permafrost. The perturbation of the peat by uplifting as well as the potential nutrient input can be detected by δ15N when related to the C/N ratio. Conen, F., Yakutin, M. V., Carle, N., and Alewell, C. (2013): δ15N natural abundance may directly disclose perturbed soil when related to C:N ratio. Rapid Commun. Mass Spectrom. 27: 1101-1104.

Holocene Vegetation Changes in Eastern Kamchatka Based on Pollen and Macrofossil Records

NASA Astrophysics Data System (ADS)

Dirksen, V.

2004-12-01

Little is known about the Quaternary climate and vegetation history of Kamchatka. Only a few previous studies have provided paleoenvironmental information for this area, but these studies have poor age control and are inconsistent To reconstruct paleoclimate and both regional and local vegetation history we are analyzing continuous, high-resolution pollen and macrofossil records from peats on Kamchatka. Thin, well-dated ash layers in these peats provide excellent age control; sections sampled thus far range in age back to 12,000 years. Herein we report results from one example, the Uka peat section (57.8oN 162.2oE; about 10 m a.s.l.). This section is located on a morainal terrace close to a small lake. The basal section is lacustrine clay with a few spores pointing to scarce vegetation under cold conditions, probably latest Pleistocene. This clay is replaced upward by limnic peat, probably early Holocene (pollen zone 1). This zone is characterized by dominance of shrub alder and birch, herbs, and ferns. The highest value (in the whole section) of sage and the absence of tree pollen suggest a treeless landscape and thin vegetation cover under still cold conditions, while increase in local aquatic pollen indicates lake filling and shrinking. In Zone 2 (ca. 8000-4000 BP), mire vegetation shows successive development of eutrophic fen including three pulses of sphagnum followed by sedge peaks. Pollen concentration is very low, probably indicating high deposition rates. A warming trend is suggested by the appearance ca. 5600 BP of tree birch, increasing to the end of zone 2, while alder strongly decreases. The most pronounced changes in both regional and local vegetation are found ca. 3800 BP, when tree birch pollen reaches its highest value and a few long-transported spruce pollen grains appear. The dominant (eutrophic) sedge is suddenly replaced by a more oligotrophic one. Such local components as grasses, shrub birch and willow increase, and total pollen concentration dramatically increases. All these features suggest drier conditions in zone 3 (3800-1200 BP), however it should be supported by further studies. Zone 4 (1200 BP to present) shows development of an oligotrophic peat bog indicated by high values of heath; the establishment of shrub pine is signaled by a sharp increase in its pollen.

Maglev performance of a double-layer bulk high temperature superconductor above a permanent magnet guideway

NASA Astrophysics Data System (ADS)

Deng, Z.; Wang, J.; Zheng, J.; Lin, Q.; Zhang, Y.; Wang, S.

2009-05-01

In order to improve the performance of the present high temperature superconducting (HTS) maglev vehicle system, the maglev performance of single- and double-layer bulk high temperature superconductors (HTSC) was investigated above a permanent magnet guideway (PMG). It is found that the maglev performance of a double-layer bulk HTSC is not a simple addition of each layer's levitation and guidance force. Moreover, the applied magnetic field at the position of the upper layer bulk HTSC is not completely shielded by the lower layer bulk HTSC either. 53.5% of the levitation force and 27.5% of the guidance force of the upper layer bulk HTSC are excited in the double-layer bulk HTSC arrangement in the applied field-cooling condition and working gap, bringing a corresponding improvement of 16.9% and 8.8% to the conventional single-layer bulk HTSC. The present research implies that the cost performance of upper layer bulk HTSC is a little low for the whole HTS maglev system.

Low-rank coal study: national needs for resource development. Volume 6. Peat

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1980-11-01

The requirements and potential for development of US peat resources for energy use are reviewed. Factors analyzed include the occurrence and properties of major peat deposits; technologies for extraction, dewatering, preparation, combustion, and conversion of peat to solid, liquid, or gaseous fuels; environmental, regulatory, and market constraints; and research, development, and demonstration (RD and D) needs. Based on a review of existing research efforts, recommendations are made for a comprehensive national RD and D program to enhance the use of peat as an energy source.

SPRUCE Deep Peat Heating (DPH) Peat Water Content and Temperature Profiles for Experimental Plot Cores, June 2014 through June 2015

DOE Data Explorer

Kluber, Lauren A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Phillips, Jana R. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hanson, Paul J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Schadt, Christopher W. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2016-01-01

This data set provides the peat water content and peat temperature at time of sampling for peat cores collected before and during the SPRUCE Deep Peat Heating (DPH) study. Cores were collected during three sampling events: 03 June 2014, 09 September 2014, and 16 June 2015. Two cores were extracted from hollow locations in each of the 10 experimental plots (4, 6, 8, 10, 11, 13, 16, 17, 19, and 20). Cores were partitioned into samples at 11 depth increments: 0-10, 10-20, 20-30, 30-40, 40-50, 50-75, 75-100, 100-125, 125-150, 150-175, and 175-200 cm below surface of the hollow.

An Enigmatic Carbonate Layer in Everglades Tree Island Peats

NASA Astrophysics Data System (ADS)

Graf, Maria-Theresia; Schwadron, Margo; Stone, Peter A.; Ross, Michael; Chmura, Gail L.

2008-03-01

Recent archaeological excavations on the heads (i.e., the most elevated and upstream parts) of several large Everglades fixed tree islands may reshape what is understood about the age and formation of these landforms, and about the role of humans in the early Everglades wetland, between 3500 and 1000 B.C. Tree islands are patches of high ground, dry enough to support trees, that rise about 1 meter above the surrounding wetland, and those islands termed "fixed" are the large teardrop-shaped islands thought to have formed over localized high points in the underlying bedrock (Figures 1a and 1b). A hard, cemented carbonate layer perched in the sediments of two tree islands in the southern Everglades was discovered by U.S. National Park Service archaeologists, and penetration of it with a concrete saw revealed that beneath the layer are unconsolidated sediments containing archaeological artifacts dating back to late-Archaic times (3000-1000 B.C.) [Schwadron, 2006].

Effectiveness of lime and peat applications on cadmium availability in a paddy soil under various moisture regimes.

PubMed

Chen, Yanhui; Xie, Tuanhui; Liang, Qiaofeng; Liu, Mengjiao; Zhao, Mingliu; Wang, Mingkuang; Wang, Guo

2016-04-01

In paddy soils, amendments and moisture play important role in the immobilization of cadmium (Cd). The effects of applying lime, peat, and a combination of both on soil Eh, pH, and Cd availability in contaminated soils were investigated under wetted (80 ± 5 % of water holding capacity) and flooded (completely submerged) conditions. In wetted soils, there was little change in Eh, compared to flooded soils where Eh reduced rapidly. Amendments of lime only or in a mixture with peat increased soil pH to different degrees, depending on the lime application rate. However, peat addition only slightly affected soil pH. The decreased Cd availability in flooded soils was related to submergence duration and was significantly lower than that in wetted soils after 14 days. Liming wetted and flooded soils decreased exchangeable Cd and increased carbonates or Fe-Mn oxides bound fractions, while peat addition transformed Cd from carbonates to organic matter bound fractions. The combined application of peat and lime generally showed better inhibitory effects on the availability of Cd than separately application of lime or peat. Higher application rates of lime, peat, or their mixture were more effective at reducing Cd contamination in flooded soil. This indicates that application of peat and lime mixture under flooded conditions was most effective for in situ remediation of Cd-contaminated soils. Further studies are required to assess the long-term effectiveness of the peat and lime mixture on Cd availability in paddy soils.

Peat accumulation in drained thermokarst lake basins in continuous, ice-rich permafrost, northern Seward Peninsula, Alaska

USGS Publications Warehouse

Jones, Miriam C.; Grosse, Guido; Jones, Benjamin M.; Anthony, Katey Walter

2012-01-01

Thermokarst lakes and peat-accumulating drained lake basins cover a substantial portion of Arctic lowland landscapes, yet the role of thermokarst lake drainage and ensuing peat formation in landscape-scale carbon (C) budgets remains understudied. Here we use measurements of terrestrial peat thickness, bulk density, organic matter content, and basal radiocarbon age from permafrost cores, soil pits, and exposures in vegetated, drained lake basins to characterize regional lake drainage chronology, C accumulation rates, and the role of thermokarst-lake cycling in carbon dynamics throughout the Holocene on the northern Seward Peninsula, Alaska. Most detectable lake drainage events occurred within the last 4,000 years with the highest drainage frequency during the medieval climate anomaly. Peat accumulation rates were highest in young (50–500 years) drained lake basins (35.2 g C m−2 yr−1) and decreased exponentially with time since drainage to 9 g C m−2 yr−1 in the oldest basins. Spatial analyses of terrestrial peat depth, basal peat radiocarbon ages, basin geomorphology, and satellite-derived land surface properties (Normalized Difference Vegetation Index (NDVI); Minimum Noise Fraction (MNF)) from Landsat satellite data revealed significant relationships between peat thickness and mean basin NDVI or MNF. By upscaling observed relationships, we infer that drained thermokarst lake basins, covering 391 km2 (76%) of the 515 km2 study region, store 6.4–6.6 Tg organic C in drained lake basin terrestrial peat. Peat accumulation in drained lake basins likely serves to offset greenhouse gas release from thermokarst-impacted landscapes and should be incorporated in landscape-scale C budgets.

Uncertainty in peat volume and soil carbon estimated using ground-penetrating radar and probing

Treesearch

Andrew D. Parsekian; Lee Slater; Dimitrios Ntarlagiannis; James Nolan; Stephen D. Sebestyen; Randall K. Kolka; Paul J. Hanson

2012-01-01

Estimating soil C stock in a peatland is highly dependent on accurate measurement of the peat volume. In this study, we evaluated the uncertainty in calculations of peat volume using high-resolution data to resolve the three-dimensional structure of a peat basin based on both direct (push probes) and indirect geophysical (ground-penetrating radar) measurements. We...

Economics of selected energy applications of peat in Panama and Costa Rica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thayer, G.R.; Ramirez E., O.; Ramirez, A.

Studies were performed to determine the economic competitiveness of peat in Costa Rica and Panama. The cases examined were (1) electrical production in Panama, and (2) industrial boilers and cement plants in Costa Rica. Based on estimates of peat mining costs and the end-use costs we calculated for each application, the price of coal and oil at which the levelized life cycle cost of energy using peat was the same as that when coal or oil was used. We found that a peat-fueled power plant in Panama would be economic if the price of fuel oil was above $0.10 permore » liter and the cost of coal was above $40.00 per metric ton delivered. In Costa Rica, peat was competitive with fuel oil for large boilers (34,000 kg of steam per hour) when the cost of oil was above $0.10 per liter. For smaller boilers (5,000 kg of steam per hour) peat was cheaper than fuel oil when oil was above $0.08 per liter. Peat would be competitive in a cement plant when fuel oil prices were above $0.075 per liter. 5 figs.« less

Comparative study of the thermal properties of mud and peat solutions applied in clinical practice.

PubMed

Beer, A M; Grozeva, A; Sagorchev, P; Lukanov, J

2003-11-01

Different peloids as e.g. mud and peat have been traditionally used for therapeutic purposes successfully, especially of there thermal actions. It was the aim of the experimental study to compare the thermal properties of two peloids, mud and peat, with a view to assessing their thermal effects when they are applied in clinical practice. The studies were carried out using peat of the marsh type of peats (Hochmoor), and curative Pomorie (Bulgaria) mud. As important parameters were determined the specific thermal capacity at constant pressure (Cp), the density of solutions (rho), the cooling rate (m), the coefficient of temperature transfer (a) of solutions and the coefficient of thermal conductivity (lambda) of solutions of peat and curative mud, compared to water bath. The comparative studies of the thermal properties of water and water solutions of peat and curative mud show that the thermal effect of the water bath is substantially smaller than that of the peat and mud applications. This difference is due to a greater extent to the high values of the dynamic viscosity, not allowing cooling by convection and protecting the surface of the skin upon applications of peloid solutions with a higher temperature.

Radiocarbon ages of different fractions of peat on coastal lowland of Bohai Bay: marine influence?

NASA Astrophysics Data System (ADS)

Shang, Zhiwen; Wang, Fu; Fang, Jing; Li, Jianfen; Chen, Yongsheng; Jiang, Xingyu; Tian, Lizhu; Wang, Hong

2018-05-01

Peat in boreholes is the most important 14C dating material used for constructing age framework. 20 bulk peat samples were collected from five boreholes, the 14C ages of two fractions (organic sediment fraction and peat fraction) of the bulk peat samples were investigated by AMS-dating and which fraction is better to help construct an age framework for the boreholes were compared and discussed. The results indicated that the peat fraction give a good dating results sequence in the boreholes, compared with the corresponding organic sediment fraction. And the dating results of organic sediment fraction show 161-6 702 years older than corresponding peat fraction, which was caused by marine influence. Then, we suggest an experience formula as y=0.99x-466.5 by the correlation analysis for correcting the marine influenced organic sediment ages within the conventional ages between 4 000 to 9 000 yrs BP, and more study should be carried out for the AMS 14C dating of the bulk organic sediments.

Groundwater flow in a coastal peatland and its influence on submarine groundwater discharge

NASA Astrophysics Data System (ADS)

Ptak, T.; Ibenthal, M.; Janssen, M.; Massmann, G.; Lenartz, B.

2017-12-01

Coastal peatlands are characterized by intense interactions between land and sea, comprising both a submarine discharge of fresh groundwater and inundations of the peatland with seawater. Nutrients and salts can influence the biogeochemical processes both in the shallow marine sediments and in the peatland. The determination of flow direction and quantity of groundwater flow are therefore elementary. Submarine groundwater discharge (SGD) has been reported from several locations in the Baltic. The objective of this study is to quantify the exchange of fresh and brackish water across the shoreline in a coastal peatland in Northeastern Germany, and to assess the influence of a peat layer extending into the Baltic Sea. Below the peatland, a shallow fine sand aquifer differs in depth and is limited downwards by glacial till. Water level and electrical conductivity (EC) are permanently measured in different depths at eight locations in the peatland. First results indicate a general groundwater flow direction towards the sea. Electrical conductivity measurements suggest different permeabilities within the peat layer, depending on its thickness and degradation. Near the beach, EC fluctuates partially during storm events due to seawater intrusion and reverse discharge afterwards. The groundwater flow will be verified with a 3D model considering varying thicknesses of the aquifer. Permanent water level and electrical conductivity readings, meteorological data and hydraulic conductivity from slug tests and grain size analysis are the base for the calibration of the numerical model.

Changes in the geodiversity of Dutch peatlands inferred from 19th and 20th century landscape paintings

NASA Astrophysics Data System (ADS)

Jungerius, Pieter Dirk; van den Ancker, Hanneke; Wevers, Nina

2013-04-01

Geodiversity is the natural and cultural range of geological, geomorphological and soil features. We analysed the large database of 19th and early 20th century paintings of Simonis and Buunk (www.Simonis-Buunk.com) to track changes in the geodiversity of Dutch peatlands since pre-photographic times. Peat dominated in two of the eight main landscapes of the Netherlands: the Lowland peats in the Holocene west and the Highland peats in the sandy Pleistocene eastern parts. Painters were mainly attracted by the lowland peats. Since more than thousand years, peat plays a major role in Dutch military security, economy, ecology and cultural life. Natural variety and cultural use resulted in a geodiversity that is unique in Europe. There are more than 100 place names with 'veen' (= peat), and surnames with 'veen' are common. Proof of the exploitation of peat for salt and fuel exists from the Roman times onwards. In the 9th century, peatlands were drained and reclaimed for growing wheat. Already in the 11th century, it was necessary to build dikes to prevent flooding, to control waterlevels to avoid further oxidation, and to convert landuse to grassland. But subsidence continued, and in the 14th century windmills were needed to drain the lands and pump the water out. In the 16th century industrial peat exploitation fuelled the rise of industries and cities. All this draining and digging caused the peat surface to shrink. The few remaining living peats are conserved by nature organisations. Geodiversity and landscape paintings In the peat landscapes, popular painting motives were high water levels, the grasslands of the 'Green Heart', the winding streams and remaining lakes. The paintings of landscapes where peat had been removed, show watermanagement adaptations: wind mills, different water levels, canals made for the transport of fuel, bridges, tow paths and the 'plassen', i.e. the lakes left after peat exploitation. The droogmakerijen (reclaimed lakes), now 2 to 5 m below sealevel, were less inspiring. Examples of geodiversity changes illustrated by the landscape paintings • Peat extraction stopped • Land use changed e.g. the deforestation of the 'Bovenlanden' • Erosion by waves and boats caused the collapse of peat islands in the artificial lakes • Peat polders of the Green Heart were sacrificed for building projects • 90% of the original wind mills were replaced by electrical and motor pumps • Horse traction was replaced by motor vehicles, which made tow paths and high wooden bridges redundant. • Dam burst risk increased and skating scenes disappeared with climate change, References Jungerius, P.D., 2010. Sea level rise and the response of the Dutch people - Adaptive strategies based on geomorphologic principles give sustainable solutions. In: Martini I.P.& Chesworth, W.(eds.) Landscapes and Societies. Springer Verlag.

Multiproxy Holocene paleoclimate records from the southern Peruvian Andes - what new can we learn from the stable carbon isotope composition of high altitude organic matter deposits?

NASA Astrophysics Data System (ADS)

Skrzypek, Grzegorz; Engel, Zbyněk

2015-04-01

Interpretation of the Central Andean paleoclimate over the last millennia still represents a research challenge demanding deeper studies [1,2]. Several high-resolution paleoclimate proxies for the last 10,000 years have been developed for the northern hemisphere. However, similar proxies are very limited for South America, particularly for high altitudes where, for example, tree-ring chronologies are not available and instrumental records are very limited. Consequently, our knowledge of high altitude climate changes in arid regions of the Peruvian Andes mainly relies on ice-core and lake deposit studies. In our study, we used a new alternative proxy for interpretation of palaeoclimate conditions based on a peat core taken from the Carhuasanta Valley at the foot of Nevado Mismi in the southern Peruvian Andes (15° 30'S, 71° 43'W, 4809m a.s.l.). The stable carbon isotope composition (δ13C) of Distichia peat reflects mainly the relative variation of the mean air temperature during subsequent growing seasons [3], and allows reconstructions of palaeotemperature changes. In contrast, peat organic carbon concentration (C % wt) records mainly wetness in the valley, directly corresponding to the changes in runoff in the upper part of the catchment. The most prominent climate changes recorded in the peat over last 4ka occurred between 3040 and 2750 cal. yrs BP. The initial warming turned to a very rapid cooling to temperatures at least 2° C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP, when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes that match the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years, when an extended warm and relatively humid period occurred between 640-155 cal. yrs BP, followed by predominantly colder and drier conditions [4]. Our study demonstrates how the δ13C value and carbon content variations in Distichia peat can be interpreted and used for verification of other multiproxy records, particularly these which are challenging for accurate dating. [1] Stansell, N.D., Rodbell, D.T., Abbott, M.B., Mark, B.G., 2013. Proglacial lake sediment records of Holocene climate change in the western Cordillera of Peru. Quat. Sci. Rev. 10, 1-14. [2] Engel Z., Skrzypek G., 2014. Reply to the comment by A. Sáez et al. on Climate in the Western Cordillera of the Central Andes over the last 4300 years. Quat. Sci. Rev. (in press 10.1016/j.quascirev.2014.12.006). [3] Skrzypek, G., Engel, Z., Chuman, T., Šefrna, L., 2011. Distichia peat - A new stable isotope paleoclimate proxy for the Andes. Earth Planet. Sci. Lett. 307(3-4), 298-308. [4] Engel, Z., Skrzypek, G., Chuman, T., Šefrna, L., Mihaljevič, M., 2014. Climate in the Western Cordillera of the Central Andes over the last 4300 years. Quat. Sci. Rev. 99, 60-77.

Stocks and fluxes of carbon associated with land use change in Southeast Asian tropical peatlands: A review

NASA Astrophysics Data System (ADS)

Hergoualc'h, Kristell; Verchot, Louis V.

2011-06-01

The increasing and alarming trend of degradation and deforestation of tropical peat swamp forests may contribute greatly to climate change. Estimates of carbon (C) losses associated with land use change in tropical peatlands are needed. To assess these losses we examined C stocks and peat C fluxes in virgin peat swamp forests and tropical peatlands affected by six common types of land use. Phytomass C loss from the conversion of virgin peat swamp forest to logged forest, fire-damaged forest, mixed croplands and shrublands, rice field, oil palm plantation, and Acacia plantation were calculated using the stock difference method and estimated at 116.9 ± 39.8, 151.6 ± 36.0, 204.1 ± 28.6, 214.9 ± 28.4, 188.1 ± 29.8, and 191.7 ± 28.5 Mg C ha-1, respectively. Total C loss from uncontrolled fires ranged from 289.5 ± 68.1 Mg C ha-1 in rice fields to 436.2 ± 77.0 Mg C ha-1 in virgin peat swamp forest. We assessed the effects of land use change on C stocks in the peat by looking at how the change in vegetation cover altered the main C inputs (litterfall and root mortality) and outputs (heterotrophic respiration, CH4 flux, fires, and soluble and physical removal) before and after conversion. The difference between the soil input-output balances in the virgin peat swamp forest and in the oil palm plantation gave an estimate of peat C loss of 10.8 ± 3.5 Mg C ha-1 yr-1. Peat C loss from other land use conversions could not be assessed due to lack of data, principally on soil heterotrophic respiration rates. Over 25 years, the conversion of tropical virgin peat swamp forest into oil palm plantation represents a total C loss from both biomass and peat of 427.2 ± 90.7 Mg C ha-1 or 17.1 ± 3.6 Mg C ha-1 yr-1. In all situations, peat C loss contributed more than 63% to total C loss, demonstrating the urgent need in terms of the atmospheric greenhouse gas burden to protect tropical virgin peat swamp forests from land use change and fires.

Soil carbon dioxide emissions from a rubber plantation on tropical peat.

PubMed

Wakhid, Nur; Hirano, Takashi; Okimoto, Yosuke; Nurzakiah, Siti; Nursyamsi, Dedi

2017-03-01

Land-use change in tropical peatland potentially results in a large amount of carbon dioxide (CO 2 ) emissions owing to drainage, which lowers groundwater level (GWL) and consequently enhances oxidative peat decomposition. However, field information on carbon balance is lacking for rubber plantations, which are expanding into Indonesia's peatlands. To assess soil CO 2 emissions from an eight-year-old rubber plantation established on peat after compaction, soil CO 2 efflux was measured monthly using a closed chamber system from December 2014 to December 2015, in which a strong El Niño event occurred, and consequently GWL lowered deeply. Total soil respiration (SR) and oxidative peat decomposition (PD) were separately quantified by trenching. In addition, peat surface elevation was measured to determine annual subsidence along with GWL. With GWL, SR showed a negative logarithmic relationship (p<0.01), whereas PD showed a strong negative linearity (p<0.001). Using the significant relationships, annual SR and PD were calculated from hourly GWL data to be 3293±1039 and 1408±214gCm -2 yr -1 (mean±1 standard deviation), respectively. PD accounted for 43% of SR on an annual basis. SR showed no significant difference between near and far positions from rubber trees (p>0.05). Peat surface elevation varied seasonally in almost parallel with GWL. After correcting for GWL difference, annual total subsidence was determined at 5.64±3.20 and 5.96±0.43cmyr -1 outside and inside the trenching, respectively. Annual subsidence only through peat oxidation that was calculated from the annual PD, peat bulk density and peat carbon content was 1.50cmyr -1 . As a result, oxidative peat decomposition accounted for 25% of total subsidence (5.96cmyr -1 ) on average on an annual basis. The contribution of peat oxidation was lower than those of previous studies probably because of compaction through land preparation. Copyright © 2017 Elsevier B.V. All rights reserved.

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

NASA Astrophysics Data System (ADS)

Smidt, Geerd; Tänzer, Detlef

2013-04-01

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.

Early age compressive strength, porosity, and sorptivity of concrete using peat water to produce and cure concrete

NASA Astrophysics Data System (ADS)

Olivia, Monita; Ismeddiyanto, Wibisono, Gunawan; Sitompul, Iskandar R.

2017-09-01

Construction in peatland has faced scarce water sources for mixing and curing concrete. It is known that peat water has high organic content and low pH that can be harmful to concrete in the environment. In some remote areas in Riau Province, contractors used peat water directly without sufficient treatments to comply with SKSNI requirements of concrete mixing water. This paper presents a study of compressive strength, porosity and sorptivity of Ordinary Portland Cement (OPC) and blended OPC-Palm Oil Fuel Ash (OPC-POFA) concrete. The specimens were mixed using natural water and peat water, then some of them were cured in fresh water and peat water. Six mixtures were investigated using a variation of cement, mixing water and curing water. Tap water is used as control mixing and curing water for all specimens. The compressive strength, porosity and sorptivity were calculated at seven and 28 days. Results indicate that the use of peat water will cause low compressive strength, high porosity and sorptivity for both OPC and OPC-POFA concrete. Using peat water and curing the specimens in tap water could improve the early strength, porosity and sorptivity of OPC concrete; however, it has an adverse effect on OPC-POFA specimens. The properties of early age concrete of both types (OPC and OPC-POFA) using peat water were as good as those with tap water. Therefore, it is suggested that peat water should be considered as mixing and curing water for concrete where tap water resources are scarce. Investigation of its long-term properties, as well as extending the observed age of concrete is recommended before any use of peat water.

Lower layers in the motor cortex are more effective targets for penetrating microelectrodes in cortical prostheses

NASA Astrophysics Data System (ADS)

Parikh, Hirak; Marzullo, Timothy C.; Kipke, Daryl R.

2009-04-01

Improving cortical prostheses requires the development of recording neural interfaces that are efficient in terms of providing maximal control information with minimal interface complexity. While the typical approaches have targeted neurons in the motor cortex with multiple penetrating shanks, an alternative approach is to determine an efficient distribution of electrode sites within the layers of the cortex with fewer penetrating shanks. The objective of this study was to compare unit activity in the upper and lower layers of the cortex with respect to movement and direction in order to inform the design of penetrating microelectrodes. Four rats were implanted bilaterally with multi-site single-shank silicon microelectrode arrays in the neck/shoulder region of the motor cortex. We simultaneously recorded unit activity across all layers of the motor cortex while the animal was engaged in a movement direction task. Localization of the electrode array within the different layers of the cortex was determined by histology. We denoted units from layers 2 and 3 and units as upper layer units, and units from layers 5 and 6 as lower layer units. Analysis of unit spiking activity demonstrated that both the upper and lower layers encode movement and direction information. Unit responses in either cortical layer of the cortex were not preferentially associated with contralateral or ipsilateral movement. Aggregate analysis (633 neurons) and best session analysis (75 neurons) indicated that units in the lower layers (layers 5, 6) are more likely to encode direction information when compared to units in the upper layers (layers 2, 3) (p< 0.05). These results suggest that electrode sites clustered in the lower layers provide access to more salient control information for cortical neuroprostheses.

Investigation of metal ions sorption of brown peat moss powder

NASA Astrophysics Data System (ADS)

Kelus, Nadezhda; Blokhina, Elena; Novikov, Dmitry; Novikova, Yaroslavna; Chuchalin, Vladimir

2017-11-01

For regularities research of sorptive extraction of heavy metal ions by cellulose and its derivates from aquatic solution of electrolytes it is necessary to find possible mechanism of sorption process and to choice a model describing this process. The present article investigates the regularities of aliovalent metals sorption on brown peat moss powder. The results show that sorption isotherm of Al3+ ions is described by Freundlich isotherm and sorption isotherms of Na+ i Ni2+ are described by Langmuir isotherm. To identify the mechanisms of brown peat moss powder sorption the IR-spectra of the initial brown peat moss powder samples and brown peat moss powder samples after Ni (II) sorption were studied. Metal ion binding mechanisms by brown peat moss powder points to ion exchange, physical adsorption, and complex formation with hydroxyl and carboxyl groups.

Insights into the effects of patchy ice layers on water balance heterogeneity in peatlands

NASA Astrophysics Data System (ADS)

Dixon, Simon; Kettridge, Nicholas; Devito, Kevin; Petrone, Rich; Mendoza, Carl; Waddington, Mike

2017-04-01

Peatlands in boreal and sub-arctic settings are characterised by a high degree of seasonality. During winter soils are frozen and snow covers the surface preventing peat moss growth. Conversely, in summer, soils unfreeze and rain and evapotranspiration drive moss productivity. Although advances have been made in understanding growing season water balance and moss dynamics in northern peatlands, there remains a gap in knowledge of inter-seasonal water balance as layers of ice break up during the spring thaw. Understanding the effects of ice layers on spring water balance is important as this coincides with periods of high wildfire risk, such as the devastating Fort McMurrary wildfire of May, 2016. We hypothesise that shallow layers of ice disconnect the growing surface of moss from a falling water table, and prevent water from being supplied from depth. A disconnect between the evaporating surface and deeper water storage will lead to the drying out of the surface layer of moss and a greater risk of severe spring wildfires. We utilise the unsaturated flow model Hydrus 2D to explore water balance in peat layers with an impermeable layer representing ice. Additionally we create models to represent the heterogeneous break up of ice layers observed in Canadian boreal peatlands; these models explore the ability of breaks in an ice layer to connect the evaporating surface to a deeper water table. Results show that peatlands with slower rates of moss growth respond to dry periods by limiting evapotranspiration and thus maintain moist conditions in the sub-surface and a water table above the ice layer. Peatlands which are more productive continue to grow moss and evaporate during dry periods; this results in the near surface mosses drying out and the water table dropping below the level of the ice. Where there are breaks in the ice layer the evaporating surface is able to maintain contact with a falling water table, but connectivity is limited to above the breaks, with limited lateral transfer of water above the ice. Conceptually this means that peatlands which tend to have lower rates of growth are largely unaffected by the presence of a shallow ice layer in the early growing season, and are able to maintain moist sub-surface conditions in the absence of precipitation. They will thus be more resistant to severe wildfire. Conversely, peatlands which tend towards higher levels of moss productivity are able to maintain moss growth during dry periods. In the presence of an ice layer this greater productivity leads to a disconnection from deep water sources, extensive drying out of moss above the ice, and a greater susceptibility to severe wildfires. Our study gives important insights into the mechanisms behind heterogeneity in burning and depth of burn in northern peatland wildfires, as well as into burn heterogeneity within peatland microtopography.

Seven centuries of atmospheric Pb deposition recorded in a floating mire from Central Italy

NASA Astrophysics Data System (ADS)

Zaccone, Claudio; Lobianco, Daniela; D'Orazio, Valeria; Miano, Teodoro M.; Shotyk, William

2016-04-01

Floating mires generally consist of emergent vegetation rooted in highly organic buoyant mats that rise and fall with changes in water level. Generally speaking, the entire floating mass (mat) is divided into a mat root zone and an underlying mat peat zone. Floating mires are distributed world-wide; large areas of floating marsh occur along rivers and lakes in Africa, the Danube Delta in Romania, the Amazon River in South America, and in the Mississippi River delta in USA, whereas smaller areas occur also in The Netherlands, Australia and Canada. While peat cores from ombrotrophic bogs have been often (and successfully) used to reconstruct changes in the atmospheric deposition of several metals (including Pb), no studies are present in literature about the possibility to use peat profiles from floating mires. To test the hypothesis that peat-forming floating mires could provide an exceptional tool for environmental studies, a complete, 4-m deep peat profile was collected in July 2012 from the floating island of Posta Fibreno, a relic mire in the Central Italy. This floating island has a diameter of ca. 30 m, a submerged thickness of about 3 m, and the vegetation is organized in concentric belts, from the Carex paniculata palisade to the Sphagnum palustre centre. The whole core was frozen cut each 1-to-2 cm (n =231), and Pb determined by quadrupole ICP-MS (at the ultraclean SWAMP lab, University of Alberta, Canada) in each sample throughout the first 100 cm, and in each odd-numbered slice for the remaining 300 cm. The 14C age dating of organic sediments (silty peat) isolated from the sample at 385 cm of depth revealed that the island probably formed ca. 700 yrs ago. Lead concentration trend shows at least two main zones of interest, i.e., a clear peak (ranging from 200 to 1600 ppm) between 110-115 cm of depth, probably corresponding to early 1960's - late 1970's, and a broad band (80-160 ppm) between 295-320 cm of depth, corresponding to approximately AD 1480-1650. Lead concentrations were normalized to those of Th, a conservative, lithophile element often used as an indicator of the abundance of mineral particles. Crustal enrichment factor values, calculated by normalizing the Pb/Th ratio in peat samples to the corresponding ratio for the Upper Continental Crust, clearly show that almost all the Pb reaching this floating isle in the last seven centuries is of anthropogenic origin. In particular, while the big peak around 100-115 cm of depth is associated with that of Sb, the band around 300 cm characterized also the trend of several other major and trace elements (i.e., Ag, Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr, Th, Tl, U, V, Y, Zn) with the exception of Sb. Although γ-spectrometry measurement (210Pb, 137Cs and 241Am) for the first 100 cm of this core is still on-going, at the best of our knowledge, this work may provide the first Pb chronology obtained from a (4 m) deep floating mire. Furthermore, it is to note that a) this floating mire could consist of the southernmost European population of Sphagnum, and b) this core shows a great potential to be used as archive of environmental changes, especially considering its high resolution (1 cm = 0.5 yr in the first 100 cm, and 2-2.5 yrs in the remaining 300 cm of depth). The Authors thank the Municipality of Posta Fibreno, Managing Authority of the Regional Natural Reserve of Lake Posta Fibreno, for allowing peat cores sampling.

Scheduling Accessory Assists Patients with Cognitive Disorders

NASA Technical Reports Server (NTRS)

2007-01-01

Recom Technologies Inc. received initial funding from NASA to research the commercial potential of an artificially intelligent planning reaction model to serve as a tool to help individuals suffering from various forms and levels of brain impairment. In 1993, the chief of the Artificial Intelligence Research Branch at Ames Research Center suggested collaborative research with Santa Clara Valley Medical Center. This partnership led to further development of the technology and funding to support clinical research from the U.S. Department of Education's National Institute on Disability and Rehabilitation Research. In 1996, Attention Control Systems Inc. was founded to market the finished device, called the Planning and Execution Assistant and Trainer (PEAT). PEAT is a pocket-sized PDA-like device with a graphical display, touchscreen controls, an electronic calendar, an address book, and a built-in phone, that cues users to start or stop scheduled activities, monitors their progress, and adjusts schedules as necessary in response to delays or calendar changes. It uses an automatic planning model developed for NASA to adjust daily plans when a situation changes. PEAT is sold as a complete system that includes software, hardware, documentation, and technical support. In addition to the flagship Pocket PEAT device, there is PEAT Phone, PC PEAT, and PEAT Link. Clinical studies of PEAT continue at Santa Clara Valley Medical Center

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

USGS Publications Warehouse

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

2007-01-01

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

Logged peat swamp forest supports greater macrofungal biodiversity than large-scale oil palm plantations and smallholdings.

PubMed

Shuhada, Siti Noor; Salim, Sabiha; Nobilly, Frisco; Zubaid, Akbar; Azhar, Badrul

2017-09-01

Intensive land expansion of commercial oil palm agricultural lands results in reducing the size of peat swamp forests, particularly in Southeast Asia. The effect of this land conversion on macrofungal biodiversity is, however, understudied. We quantified macrofungal biodiversity by identifying mushroom sporocarps throughout four different habitats; logged peat swamp forest, large-scale oil palm plantation, monoculture, and polyculture smallholdings. We recorded a total of 757 clusters of macrofungi belonging to 127 morphospecies and found that substrates for growing macrofungi were abundant in peat swamp forest; hence, morphospecies richness and macrofungal clusters were significantly greater in logged peat swamp forest than converted oil palm agriculture lands. Environmental factors that influence macrofungi in logged peat swamp forests such as air temperature, humidity, wind speed, soil pH, and soil moisture were different from those in oil palm plantations and smallholdings. We conclude that peat swamp forests are irreplaceable with respect to macrofungal biodiversity. They host much greater macrofungal biodiversity than any of the oil palm agricultural lands. It is imperative that further expansion of oil palm plantation into remaining peat swamp forests should be prohibited in palm oil producing countries. These results imply that macrofungal distribution reflects changes in microclimate between habitats and reduced macrofungal biodiversity may adversely affect decomposition in human-modified landscapes.

The Characteristics of Electrical and Physical Properties of Peat Soil in Rasau Village, West Kalimantan

NASA Astrophysics Data System (ADS)

Aminudin, A.; Hasanah, T. R.; Iryati, M.

2018-05-01

The Electrical and physical properties can be used as indicators for measuring soil conditions. One of the methods developed in agricultural systems to obtain information on soil conditions is through measuring of electrical conductivity. Peat soil is one of the natural resources that exist in Indonesia. This study aims to determine the characteristics of peat soil in Rasau village, West Kalimantan. This research was conducted by the properties of electrical conductivity and water content using 5TE Water Contents and EC Sensor equipment, but also to know the change of physical nature of peat soil covering peat soil and peat type. The results showed that the electrical conductivity value of 1-4 samples was 0.02 -0.29 dS/m and the volume water content value (VWC) was 0.255-0.548 m3/m3 and the physical characteristics obtained were peat colour brown to dark brown that allegedly the soil still has a very high content of organic material derived from weathering plants and there are discovery of wood chips, wood powder and leaf powder on the ground. Knowing the information is expected to identify the land needs to be developed to be considered for future peat soil utilization.

Interface roughness induced asymmetric magnetic property in sputter-deposited Co/CoO/Co exchange coupled trilayers

NASA Astrophysics Data System (ADS)

Wang, J.; Sannomiya, T.; Shi, J.; Nakamura, Y.

2012-04-01

The effect of interface roughness on magnetic properties of exchange coupled polycrystalline Co/CoO(tAF)/Co trilayers has been investigated by varying antiferromagnetic layer (CoO) thickness. It has been found that the upper CoO/Co interface becomes rougher with increasing CoO layer thickness, resulting in stronger exchange bias of the upper interface than the lower one. The interfacial exchange coupling is strengthened by the increase of defect-generated uncompensated antiferromagnetic spins; such spins form coupling with spins in the Co layer at the interface. As a result, the CoO layer thickness dependence of exchange bias is much enhanced for the upper Co layer. The transition from anisotropic magnetoresistance to isotropic magnetoresistance for the top Co layer has also been found. This could be attributed to the defects, probably partial thin oxide layers, between Co grains in the top Co layer that leads a switch from spin-orbit scattering related magnetoresistance to spin-dependent electron scattering dominated magnetoresistance.

Influence of Biodegradation on the Organic Compounds Composition of Peat.

NASA Astrophysics Data System (ADS)

Serebrennikova, Olga; Svarovskaya, Lidiya; Duchko, Maria; Strelnikova, Evgeniya; Russkikh, Irina

2016-06-01

Largest wetland systems are situated on the territory of the Tomsk region. They are characterized by the high content of organic matter (OM), which undergoes transformation as a result of physical, chemical and biological processes. The composition of peat OM is determined by the nature of initial peat-forming plants, their transformation products and bacteria. An experiment in stimulated microbial impact was carried out for estimating the influence of biodegradation on the composition of peat lipids. The composition of the functional groups in the bacterial biomass, initial peat and peat after biodegradation was determined by IR-spectroscopy using the spectrometer NICOLET 5700. The IR spectra of peat and bacteria organic matter are characterized by the presence of absorption bands in ranges: 3400-3200 cm-1, which refers to the stretching vibrations of OH-group of carboxylic acids and various types of hydrogen bonds; 1738-1671 cm-1 - characteristic stretching vibrations of the C = O group of carboxylic acids and ketones; 1262 cm-1 - stretching vibrations of C-O of carboxylic acids. Group and individual composition of organic compounds in studied samples was determined by gas chromatography-mass-spectrometry.

The peats of Costa Rica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thayer, G.R.; Williamson, K.D. Jr.; Ramirez, O.

The authors compare the competitive position of peat for energy with coal, oil, and cogenerative systems in gasifiers and solid-fuel boilers. They also explore the possibility for peat use in industry. To identify the major factors, they analyze costs using a Los Alamos levelized cost code, and they study parametric costs, comparing peat production in constant dollars with interest rates and return on investment. They consider costs of processing plant construction, sizes and kinds of boilers, retrofitting, peat drying, and mining methods. They examine mining requirements for Moin, Changuinola, and El Cairo and review wet mining and dewatering methods. Peatmore » can, indeed, be competitive with other energy sources, but this depends on the ratio of fuel costs to boiler costs. This ratio is nearly constant in comparison with cogeneration in a steam-only production system. For grate boilers using Costa Rican high-ash peat, and for small nonautomatic boilers now used in Costa Rica, the authors recommend combustion tests. An appendix contains a preliminary mining plan and cost estimate for the El Cairo peat deposit. 8 refs., 43 figs., 19 tabs.« less

Dependency of Ecosystem Respiration in a Cool Temperate Bog on Peat Temperature and Water Table

NASA Astrophysics Data System (ADS)

Moore, T.; Lafleur, P.; Roulet, N.; Frolking, S.

2003-12-01

We measured ecosystem respiration (ER) from nighttime net ecosystem exchange of carbon dioxide determined from an eddy covariance tower located in a large ombrotrophic bog near Ottawa, Canada. Measurements were made from May to October over 5 years, 1998 to 2002. Ecosystem respiration ranged from <0.05 mg CO2/m2/s in spring (May) and late fall (late October) to 0.10-0.15 mg CO2/m2/s during the summer (July-August). As anticipated, there was a strong relationship between ER and peat temperatures, such as at a depth of 5 cm (r2 = 0.63). Q10 over 5° to 15° C varied from 2.2 to 4.2 depending upon the choice of temperature level and location within a hummock or hollow. Unexpected for a wetland ecosystem, there was only a weak relationship between ER and water table position (r2 = 0.11). Comparison of ER in early and late summer, 2002 with similar surface temperature revealed no significant difference in ER. A laboratory incubation of peat cores at different moisture contents showed that CO2 production was reduced by drying in the surface samples, but there was little decrease in samples from below a depth of 30 cm. We believe that the lack of correlation between ER and water table position in this ecosystem results from an increase in CO2 production at depth compensating a decrease in production of CO2 by heterotrophic respiration in the near surface layers and autotrophic respiration in the moss community.

Bacterial and fungal community composition and functioning of two different peatlands in China

NASA Astrophysics Data System (ADS)

Wang, Meng; Tian, Jianqing; Bu, Zhaojun; Chen, Huai; Zhu, Qiuan; Peng, Changhui

2017-04-01

Peatlands are important carbon sinks which store one third of the global soil carbon ( 550 Gt) with only 3% of the land surface. The slow rate of organic matter decomposition associated with low microbial diversity and limited functioning under cold, acidic and anoxic condition is of critical importance in controlling biogeochemical cycles in northern peatlands. To evaluate the variation in microbial community composition and functionality can advance our understanding of the underlying mechanisms of the biogeochemical processes and interactions. However, there is still a lack of information for Chinese peatlands. Here, we sampled peat profiles at three different depths (10-20, 30-40 and 60-70 cm) from two typical peatlands in China: a rich fen in Qinghai-Tibet Plateau (QTP) and a poor fen in the Changbai Mountains (CBM). We investigated the bacterial (16S rRNA) and fungal (ITS2) community composition and diversity with high-throughput sequencing and predicted the metagenome functioning with PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States). The results showed that Proteobacteria, Acidobacteria and Actinobacteria were the most abundant bacterial phyla in the upper peat layer (10-20 cm) for both sites, with increasing abundance of Chloroflexi and Bacteroidetes down to the saturated zone (60-70 cm in CMB; 30-40 and 60-70 cm in QTP). For fungi, Ascomycota, Ciliophora and Basidiomycota were the most abundant phyla in both sites, with decreasing Ciliophora abundance down to the saturated zone. The α-diversity of both bacterial and fungal showed a decreasing trend with depth in QTP, with the largest diversity occurring at the depth of 30-40 cm in CMB. Regardless of sampling sites, the bacterial communities at the depth of 60-70 cm were more similar than the other depths. The fungal community was clustered into two groups, corresponding to two sampling sites. The variation in fungal community with depth was larger in QTP than in CBM. The predicted abundances of KEGG orthologs (KOs) assigned to the metabolism of amino acid, lipid and xenobiotics, as well as environmental adaptation, were decreased with depth in CBM, with energy metabolism showing the opposite trend. In contrast, the KO abundances of amino acid and lipid metabolism and environmental adaptation were the highest in the middle layer (30-40 cm) in QTP, where the KO abundance of energy metabolism was the lowest. In general, the difference in predicted metagenome functioning between sites was less obvious than between depths. These results highlight the important role of hydrology in shaping the microbial community in minerotrophic peatlands. The effect of environmental drivers on microbial diversity and functioning may be mediated by shifting in hydrological dynamics (e.g. land use change and desiccation) which should be considered under future global change condition.

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

NASA Astrophysics Data System (ADS)

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

2013-10-01

Artificial drainage of peatlands causes dramatic changes in the release of greenhouse gases and in the export of dissolved carbon (C) and nutrients to downstream ecosystems. Rewetting anthropogenically altered peatlands offers a possibility to reduce nitrogen (N) and C losses. In this study, we investigate the impact of drainage and rewetting on the cycling of dissolved C and N as well as on dissolved gases over a period of 1 yr and 4 month, respectively. The peeper technique was used to receive a high vertical sampling resolution. Within one Atlantic bog complex a near natural site, two drained grasslands sites with different mean water table positions, and a former peat cutting area rewetted 10 yr ago were chosen. Our results clearly indicate that drainage increased the concentration of dissolved organic carbon (DOC), ammonia, nitrate and dissolved organic nitrogen (DON) compared to the near natural site. Drainage depth further determined the release and therefore the concentration level of DOC and N species, but the biochemical cycling and therefore dissolved organic matter (DOM) quality and N species composition were unaffected. Thus, especially deep drainage can cause high DOC losses. In general, DOM at drained sites was enriched in aromatic moieties as indicated by SUVA280 and showed a higher degradation status (lower DOC to DON ratio) compared to the near natural site. At the drained sites, equal C to N ratios of uppermost peat layer and DOC to DON ratio of DOM in soil solution suggest that the uppermost degraded peat layer is the main source of DOM. Nearly constant DOC to DON ratios and SUVA280 values with depth furthermore indicated that DOM moving downwards through the drained sites remained largely unchanged. DON and ammonia contributed most to the total dissolved nitrogen (TN). The subsoil concentrations of nitrate were negligible due to strong decline in nitrate around mean water table depth. Methane production during the winter months at the drained sites moved downwards to areas which were mostly water saturated over the whole year (>40 cm). Above these depths, the recovery of the water table in winter months led to the production of nitrous oxide around mean water table depth at drained sites. 10 yr after rewetting, the DOM quality (DOC to DON ratio and SUVA280) and quantity were comparable to the near natural site, indicating the re-establishment of mostly pristine biochemical processes under continuously water logged conditions. The only differences occur in elevated dissolved methane and ammonia concentrations reflecting the former disturbance by drainage and peat extraction. Rewetting via polder technique seems to be an appropriate way to revitalize peatlands on longer timescales and to improve the water quality of downstream water bodies.

Near coast sedimentary stratigraphy as a proxy for climatic instability

NASA Astrophysics Data System (ADS)

McLivenny, J.

2009-04-01

Several studies have indicated a link between climatic deterioration and dune stability (Wilson 2002, Issar 2003, Dawson et al 2004). The frequency and magnitude of storms have been cited as a key variable in the stability of large dune systems. For the stratigraphy of dune systems to act as a regional climatic proxy there must be a good regional relationship between known climatic events and regionally correlated stratigraphic changes. Dunnet Bay in Caithness, Northern Scotland was chosen as a study site to look at the relationship between dune stability and climatic change during the late Holocene in Northern Scotland. Dunnet Bay was chosen for its physical attributes which make it an excellent natural sediment trap. Tucked in between headlands which act as barriers to long-shore transport the predominant movement of sediment there is straight onshore, with only minor amounts being lost to the sea. The immediate back-dune stratigraphy, colloquially known as "links", provided evidence of peat formation and dune stability. Stratigraphy was mapped using traditional field techniques and ground penetrating radar. The cores consisted mostly of massive layers of sand interleaved with peat. Sand layers were dated with optically stimulated luminescence (OSL) and interpreted as reflecting high wind energy regimes transporting sand inland. Peat layers were C14 dated and taken as representing climatic stability. Stratigraphy was mapped using hand auguring, percussion coring, and open sections. Ground penetrating radar was also used to look at the continuity of key layers. OSL dating in two open sections showed dates obtained from the first section (1790 AD ±70, 53 BC ± 100, 300 BC ± 100, 400 BC ± 100) mapped to the top of the second section (1800 AD ± 100, 1500 BC ± 200, 2900 BC ± 300) which was consistent with stratigraphy increasing sediment thickness towards the centre of the bay. The results were consistent with acquired C14 dates from selected peat layers. Taken collectively the results are consistent with some known episodes of climatic instability which occurred during the mid Holocene with instability phases occurring in Dunnet from approximately 6300- 4250 yrs BP, associated with climatic deterioration between 6000 - 5,200 Yrs BP (Lamb 1995) and dune instability between 2560 - 3900 Yrs BP, associated with an abrupt change of climate (Anderson 1995) In addition to the luminescence dates, 31 luminescence profiling dates were acquired in order to look at the continuity of the age vs. depth profile. Luminescence profile dates are small samples that require less preparation prior to luminescence measurement than full luminescence dating. Although larger errors are associated with luminescence profiling, it offered means of identifying at lesser cost the possible occurrence of mixing between eroded layers. The stratigraphic chronology was compared to other local and regional dune studies and periods of climatic deterioration found in other proxies. The GISP2 ice core (Greenland Ice Sheet Project) was found to provide chemical proxies for North Atlantic storminess which partially explained our observed stratigraphy (O`brien et al 1995). It is concluded that changes in dune stability at a regional scale are also influenced by local variables, so that one should be careful when attempting to draw stratigraphy to climate change. Key References: Issar, A. (2003) Climate changes during the Holocene and their impact on hydrological systems. Published by the Cambridge University Press 2003. Wilson, P. (2002) Holocene coastal dune development on the South Erridale peninsula, Wester Ross, Scotland. Scottish Journal of Geology, 38, 1, 5-13. Dawson, S., smith, D., Jordan, J., and Dawson D. G. (2004) Late Holocene coastal sand movements in the outer Hebrides N. W. Scotland. Marine Geology 210, 281-306 O`Brien, S. M. Mayewski, P.A. Meeker, L. D., Meese, D. A., Twickler, M. S. & Whitlow, S. I. (1995) Complexity of the Holocene Climate as reconstructed from a Greenland ice core. Science 270, pp 1962-1964 Lamb, H. (1995) Climate, History and the Modern World. Published by Routledge ISBN 0415127343, 9780415127349 2nd ed. Anderson, D. E. (1995) An abrupt mid-Holocene decline of pinus sylvestris in Glen Torridon, north west Scotland: Implications for paleoclimatic change. School of Geography and the Environment Research papers, Oxford

Morphological evolution in dewetting polystyrene/polyhedral oligomeric silsesquioxane thin film bilayers.

PubMed

Paul, Rituparna; Karabiyik, Ufuk; Swift, Michael C; Hottle, John R; Esker, Alan R

2008-05-06

Morphological evolution in dewetting thin film bilayers of polystyrene (PS) and a polyhedral oligomeric silsesquioxane (POSS), trisilanolphenyl-POSS (TPP), was studied as a function of annealing temperature and annealing time. The results demonstrate unique dewetting morphologies in PS/TPP bilayers at elevated temperatures that are significantly different from those typically observed in dewetting polymer/polymer bilayers. During temperature ramp studies by optical microscopy (OM) in the reflection mode, PS/TPP bilayers form cracks with a weak optical contrast at approximately 130 degrees C. The crack formation is attributed to tensile stresses within the upper TPP layer. The weak optical contrast of the cracks observed in the bilayers for annealing temperatures below approximately 160 degrees C is consistent with the cracking and dewetting of only the upper TPP layer from the underlying PS layer. The optical contrast of the morphological features is significantly enhanced at annealing temperatures of >160 degrees C. This observation suggests dewetting of both the upper TPP and the lower PS layers that results in the exposure of the silicon substrate. Upon annealing the PS/TPP bilayers at 200 degrees C in a temperature jump experiment, the upper TPP layer undergoes instantaneous cracking as observed by OM. These cracks in the upper TPP layer serve as nucleation sites for rapid dewetting and aggregation of the TPP layer, as revealed by OM and atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) results indicated that dewetting of the lower PS layer ensued for annealing times >5 min and progressed up to 90 min. For annealing times >90 min, OM, AFM, and XPS results revealed complete dewetting of both the layers with the formation of TPP encapsulated PS droplets.

Colloid-facilitated metal transport in peat filters.

PubMed

Kalmykova, Yuliya; Rauch, Sebastien; Strömvall, Ann-Margret; Morrison, Greg; Stolpe, Björn; Hasselliöv, Martin

2010-06-01

The effect of colloids on metal retention in peat columns was studied, with the focus on colloids from two sources-organic matter leached from peat, and introduced organic and hydrous ferric oxide (HFO) colloids. A significant fraction of metals was found to be associated with peat-produced organic colloids; however the concentrations of organic colloids leached are low (trace concentrations) and temporal and have a limited effect on the efficiency of peat filters. In contrast, the presence of organic and HFO colloids in the input water causes a significant decrease in the performance of peat filters. Organic colloids were identified as the main vector of cadmium, copper, nickel, and zinc, while lead is transported by both organic and HFO colloids. The colloidal distribution of metals obtained in this study has important implications for the mobility of trace metals in porous media. The occurrence of colloids in the input waters and their characteristics must be considered when designing water treatment facilities.

Mycorrhizal synthesis between Boletus edulis species complex and rockroses (Cistus sp.).

PubMed

Águeda, Beatriz; Parladé, Javier; Fernández-Toirán, Luz Marina; Cisneros, Óscar; de Miguel, Ana María; Modrego, María Pilar; Martínez-Peña, Fernando; Pera, Joan

2008-10-01

Ectomycorrhizas of Boletus aereus, Boletus edulis, and Boletus reticulatus were synthesized with Cistus sp. under laboratory conditions using synthesis tubes filled with a mixture of sterilized peat-vermiculite and nutrient solution. The fungal strains isolated from sporocarps were identified by molecular techniques. The inoculated seedlings were grown for 4-5 months. The ectomycorrhizas formed were described based on standard morphological and anatomical characters. The three ectomycorrhizas described were very similar, with white monopodial-pinnate morphology, a three-layered plectenchymatous mantle on plan view and boletoid rhizomorphs.

Impact of climate warming on upper layer of the Bering Sea

NASA Astrophysics Data System (ADS)

Lee, Hyun-Chul; Delworth, Thomas L.; Rosati, Anthony; Zhang, Rong; Anderson, Whit G.; Zeng, Fanrong; Stock, Charles A.; Gnanadesikan, Anand; Dixon, Keith W.; Griffies, Stephen M.

2013-01-01

The impact of climate warming on the upper layer of the Bering Sea is investigated by using a high-resolution coupled global climate model. The model is forced by increasing atmospheric CO2 at a rate of 1% per year until CO2 reaches double its initial value (after 70 years), after which it is held constant. In response to this forcing, the upper layer of the Bering Sea warms by about 2°C in the southeastern shelf and by a little more than 1°C in the western basin. The wintertime ventilation to the permanent thermocline weakens in the western Bering Sea. After CO2 doubling, the southeastern shelf of the Bering Sea becomes almost ice-free in March, and the stratification of the upper layer strengthens in May and June. Changes of physical condition due to the climate warming would impact the pre-condition of spring bio-productivity in the southeastern shelf.

Citizen's dosimeter

DOEpatents

Klemic, Gladys [Naperville, IL; Bailey, Paul [Chicago, IL; Breheny, Cecilia [Yonkers, NY

2008-09-02

The present invention relates to a citizen's dosimeter. More specifically, the invention relates to a small, portable, personal dosimetry device designed to be used in the wake of a event involving a Radiological Dispersal Device (RDD), Improvised Nuclear Device (IND), or other event resulting in the contamination of large area with radioactive material or where on site personal dosimetry is required. The card sized dosimeter generally comprises: a lower card layer, the lower card body having an inner and outer side; a upper card layer, the layer card having an inner and outer side; an optically stimulated luminescent material (OSLM), wherein the OSLM is sandwiched between the inner side of the lower card layer and the inner side of the upper card layer during dosimeter radiation recording, a shutter means for exposing at least one side of the OSLM for dosimeter readout; and an energy compensation filter attached to the outer sides of the lower and upper card layers.

Dementia of frontal lobe type and motor neuron disease. A Golgi study of the frontal cortex.

PubMed Central

Ferrer, I; Roig, C; Espino, A; Peiro, G; Matias Guiu, X

1991-01-01

Neuropathological findings in a 38 year old patient with dementia of frontal lobe type and motor neuron disease included pyramidal tracts, myelin pallor and neuron loss, gliosis and chromatolysis in the hypoglossal nucleus, together with frontal atrophy, neuron loss, gliosis and spongiosis in the upper cortical layers of the frontal (and temporal) lobes. Most remaining pyramidal and non-pyramidal neurons (multipolar, bitufted and bipolar cells) in the upper layers (layers II and III) of the frontal cortex (area B) had reduced dendritic arbors, proximal dendritic varicosities and amputation of dendrites as revealed in optimally stained rapid Golgi sections. Pyramidal cells in these layers also showed depletion of dendritic spines. Neurons in the inner layers were preserved. Loss of receptive surfaces in neurons of the upper cortical layers in the frontal cortex are indicative of neuronal disconnection, and are "hidden" contributory morphological substrates for the development of dementia. Images PMID:1744652

Decoding the Secrets of Carbon Preservation and GHG Flux in Lower-Latitude Peatlands

NASA Astrophysics Data System (ADS)

Richardson, C. J.; Flanagan, N. E.; Wang, H.; Ho, M.; Hodgkins, S. B.; Cooper, W. T.; Chanton, J.; Winton, S.

2017-12-01

The mechanisms regulating peat decomposition and C carbon storage in peatlands are poorly understood, particularly with regard to the importance of the biochemical compounds produced by different plant species and in turn peat quality controls on C storage and GHG flux. To examine the role of carbon quality in C accretion in northern compared to tropical peatlands we completed field and lab studies on bog peats collected in Minnesota, North Carolina, Florida and Peru to answer three fundamental questions; 1) is tropical peat more recalcitrant than northern peat 2) does the addition of aromatic and phenolic C compounds increase towards the tropics 3) do differences in the chemical structure of organic matter explain variances in carbon storage and GHG flux in tropical versus northern peatlands? Our main hypothesize is that high concentrations of phenolics and aromatic C compounds produced in shrub and tree plant communities in peatlands coupled with the fire production of biochar aromatics in peatlands may provide a dual biogeochemical latch mechanism controlling microbial decomposition of peat even under higher temperatures and seasonal drought. By comparing the peat bog soil cores collected from the MN peat bogs, NC Pocosins, FL Everglades and Peru palm swamps we find that the soils in the shrub-dominant Pocosin contain the highest phenolics, which microbial studies indicate have the strongest resistance to microbial decomposition. A chemical comparison of plant driven peat carbon quality along a north to south latitudinal gradient indicates that tropical peatlands have higher aromatic compounds, and enhanced phenolics, especially after light fires, which enhances C storage and affect GHG flux across the latitudinal gradient.

Insights and issues with estimating Holocene peatland carbon stocks: a synthesis and review

NASA Astrophysics Data System (ADS)

Loisel, Julie; Yu, Zicheng

2014-05-01

Of all terrestrial ecosystems, peatlands are arguably the most efficient at sequestering carbon (C) over long time scales. However, ongoing and projected climate change could shift the balance between peat production and organic matter decomposition, potentially impacting the peat C sink capacity and modifying peat C fluxes to the atmosphere. Yet, the sign and magnitude of the peatland - C - climate feedback remain uncertain and difficult to assess because of large uncertainties in regional peat C stocks and limited understanding of peatland responses to climate change. Here we present results from the most comprehensive compilation of Holocene peat soil properties with associated carbon (C) and nitrogen (N) accumulation rates for northern peatlands. Our database consists of 268 peat cores from 215 sites located north of 45N. It encompasses regions within which peat C data have only recently become available, such as the West Siberia Lowlands, the Hudson Bay Lowlands, Kamchatka in Far East Russia, and the Tibetan Plateau. The database is publicly available at https://peatlands.lehigh.edu. Several scaling-up methods for estimating present-day peatland C stocks are presented, and uncertainties associated with each one of them are addressed. Likewise, the assumptions for calculating peat C volumes are discussed in light of conceptual models of spatial heterogeneity in peatland structure and function. We also examine the theoretical basis and underlying assumptions for the models of peatland lateral expansion and peat vertical growth used in estimating paleo peatland C stocks. Finally, we explore the importance of the fen-to-bog transition and of permafrost aggradation on C sequestration.

Ries Bunte Breccia revisited: Indications for the presence of water in Itzing and Otting drill cores and implications for the emplacement process

NASA Astrophysics Data System (ADS)

Pietrek, Alexa; Kenkmann, Thomas

2016-07-01

We reassessed two drill cores of the Bunte Breccia deposits of the Ries crater, Germany. The objectives of our study were the documentation of evidence for water in the Bunte Breccia, the evaluation of how that water influenced the emplacement processes, and from which preimpact water reservoir it was derived. The Bunte Breccia in both cores can be structured into a basal layer composed mainly of local substrate material, overlain by texturally and compositionally diverse, crater-derived breccia units. The basal layer is composed of the youngest sediments (Tertiary clays and Upper Jurassic limestone) and has a razor-sharp boundary to the upper breccia units, which are composed of older rocks of Upper Jurassic to Upper Triassic age. Sparse material exchange occurred between the basal layer and the rest of the Bunte Breccia. Fluids predominantly came from the Tertiary and the Upper Triassic sandstone formation. In the basal layer, Tertiary clays were subjected to intense, ductile deformation, indicating saturation with water. This suggests that water was mixed into the matrix, creating a fluidized basal layer with a strong shear localization. In the upper units, Upper Triassic sandstones are intensely deformed by granular flow. The texture requires that the rocks were disaggregated into granular sand. Vaporization of pore water probably aided fragmentation of these rocks. In the Otting core, hot suevite (T > 600 °C) covered the Bunte Breccia shortly after its emplacement. Vertically oriented gas escape pipes in suevite partly emanate directly at the contact to the Bunte Breccia. They indicate that the Bunte Breccia contained a substantial amount of water in the upper part that was vaporized and escaped through these vents.

Controls on Methanogenesis in Organic-Rich Anaerobic Environments

NASA Astrophysics Data System (ADS)

Wilson, R.; Tfaily, M.; Chanton, J.; Rich, V. I.; Saleska, S. R.; Holmes, B.; Langford, L.; Hanson, P. J.; Bridgham, S. D.; Hopple, A.; Keller, J.; Cory, A.; Kostka, J. E.

2017-12-01

Peatlands contain an amount of C equal to half the CO2 in the atmosphere. That C is stored as organic C (OC) in peat deposits which form when plant productivity exceeds heterotrophic respiration. This balance has been attributed to cold, anaerobic, low pH conditions which slow microbial respiration rates, high aromatic content which may inhibit microbial decomposition, and recalcitrance of OC under terminal electron-acceptor (TEA) depleted conditions. Peat has been described as a potential C bomb which could release Gt of C into the atmosphere if rising global temperatures shifted this balance in favor of increased microbial respiration. At the Spruce and Peatlands Responses Under Changing Environments (SPRUCE) experimental site in Minnesota, U.S.A., peat up to 2 m deep was heated (+2.25°C to +9°C above ambient) both in situ and in laboratory incubations to test the response of microbial respiration to increasing temperatures. Our results demonstrated (1) that temperature did not influence CO2 or CH4 production rates in deep anaerobic peat, (2) that microbial decomposition was dominated by dissolved OC rather than the solid phase peat, and (3) that microbial decomposition in surface peat may become more methanogenic with warming. This shift towards higher CH4 production relative to CO2 has significant climate change implications since CH4 is a much stronger greenhouse gas than CO2. Under TEA-poor, anaerobic conditions, such as peat deposits, thermodynamic principles dictate that cellulose, the dominant OC form in Sphagnum peat, should be mineralized into equimolar CO2 and CH­4. However, deviations from this predicted ratio abound. The literature of rumen, a system similar to peat in many ways, revealed a potential mechanism for sustaining elevated CO2 production without accumulating inhibitory H2. Using FTICRMS, we found ubiquitous hydrogenation of unsaturated OC which could be acting as TEAs in peat deposits. This mechanism has the further advantages of alleviating the toxicity of aromatic compounds and potentially making otherwise recalcitrant aromatic molecules susceptible to anaerobic decomposition thereby providing a critical step in the diagenesis of peat. Incubation experiments adding H2 support these findings and incubations of irradiated peat suggest an abiotic contribution to CO2 production.

The Multi-Stage History of Mt. Sharp

NASA Technical Reports Server (NTRS)

Allen, C.; Dapremont, A.

2013-01-01

The Curiosity rover is exploring Gale crater and Mt. Sharp, Gale's 5-km high central mound. We are investigating the history of alteration and erosion of Mt. Sharp using orbital imagery, spectroscopy and rover observations. Our results suggest a significant time gap between emplacement of the upper and lower sections of the mound. Crater counts show that the lower mound was formed soon after Gale itself, and that it contains distinct units ranging in altitude from approximately -4,500 to -1,800 m. Spectral data suggest that many units contain phyllosilicates. We found that these clay-bearing rocks occur in distinct layers concentrated below -2,900 m. Parts of the lower mound exhibit a transition from clays to sulfates with increasing altitude. The lower mound shows evidence of flowing water, including canyons and inverted channels. Wind erosion produced km-scale yardangs and scalloped cliffs. Our mapping shows that many yardangs in the lower mound are clay-bearing, with a predominant orientation of around N-S. Curiosity's ground-level images show myriad fine-scale, mainly horizontal layers in the lower mound. The rover has found stream beds and conglomerates, indicating that water once flowed on the crater floor. Drilling near the deepest point in Gale produced abundant clay, providing additional evidence of aqueous alteration. Upper mound units range in altitude from -2,100 m to +500 m, and mantle the lower mound above an angular unconformity. Most upper mound units are composed of layers. The formation age of the upper mound is unknown, since few craters are preserved. Clay-bearing layers are detectable in several locations, mainly at altitudes near -2,000 m. There is no evidence of water flow, but wind erosion has scalloped the surfaces and edges of layers, and fine-scale yardangs are common. Correlations between yardangs and clay spectra are apparent only in the lowermost units of the upper mound. Yardang orientations vary, and include N-S, NW-SE, and NE-SW. Upper mound units resemble the planet-wide Medusae Fossae formation, dated as Hesperian and argued to be composed of ignimbrites. Medusae Fossae layers are easily eroded by wind, and our mapping demonstrates their resemblance to upper mound fine-scale yardangs. The history of Mt. Sharp started with deposition and lithification of sediments shortly after crater formation. Some lower mound layers were partially altered to clays and sulfates, and water formed streams and canyons. Wind erosion of the lower mound produced large-scale yardangs, particularly in clay-rich layers, oriented generally N-S. Upper mound units were emplaced following a considerable period of wind erosion. The absence of water flow on the upper mound suggests that these units were emplaced after atmospheric loss rendered water unstable at the surface. The shift in dominant wind direction, as indicated by yardang orientations, also argues for a time gap between erosion of the lower and upper mound. These observations are consistent with upper mound units being related to the Hesperian Medusae Fossae formation. During 2014 Curiosity is expected to reach the foot of Mt. Sharp and ascend through the clay-rich layers, into the sulfate-rich layers, and possibly past the interface with the upper mound. This will be a unique opportunity to field check geologic models on the surface of Mars.

Characterization and source apportionment of particulate matter < or = 2.5 micrometer in Sumatra, Indonesia, during a recent peat fire episode.

PubMed

See, Siao Wei; Balasubramanian, Rajasekhar; Rianawati, Elisabeth; Karthikeyan, Sathrugnan; Streets, David G

2007-05-15

An intensive field study was conducted in Sumatra, Indonesia, during a peat fire episode to investigate the physical and chemical characteristics of particulate emissions in peat smoke and to provide necessary data for source-receptor analyses. Ambient air sampling was carried out at three different sites located at varying distances from the peatfires to determine changes in mass and number concentrations of PM2.5 and its chemical composition (carbonaceous and nitrogenous materials, polycyclic aromatic hydrocarbons, water-soluble inorganic and organic ions, and total and water-soluble metals). The three sites represent a rural site directly affected by the local peat combustion, a semirural site, and an urban site situated downwind of the peat fires. The mass concentration of PM2.5 and the number concentration of airborne particles were as high as 1600 microg/m3 and 1.7 x 10(5) cm(-3), respectively, in the vicinity of peat fires. The major components of PM2.5 in peat smoke haze were carbonaceous particles, particularly organic carbon, NO3-, and SO4(2-), while the less abundant constituents included ions such as NH4+, NO2-, Na+, K+, organic acids, and metals such as Al, Fe, and Ti. Source apportionment by chemical mass balance receptor modeling indicates that peat smoke can travel long distances and significantly affect the air quality at locations downwind.

Biochar as a Substitute for Peat in Greenhouse Growing Media: Soil Water Characteristics and Carbon Leaching Dynamics

NASA Astrophysics Data System (ADS)

Johnson, M. S.; Hilbert, I.; Jollymore, A. J.

2012-12-01

Biochar (charcoal derived from waste biomass via pyrolysis) has the potential to be used as part of regional scale carbon sequestration strategies. By providing a stable form of carbon that is resistant to decay in soils, biochar can be utilized in a wide range of applications to improve the sustainability of land use management practices. Due to its high water holding capacity, surface area and charge density, it could provide a substitute for peat that is widely used in horticultural activities. Globally, peat production in 2010 amounted to 23.4 Mt, with more than a third of this used for horticulture. In Canada, essentially all peat produced is used for horticulture, with each ton of peat extracted also contributing about 0.7 t CO2e in combined greenhouse gas emissions related to production, transportation and use of peat. We evaluated biochar produced on farm from red alder as a peat substitute in terms of soil water characteristics and carbon leaching in greenhouse growing media (e.g. potting mix). Biochar mixing ratios of 10% (v/v) and greater provided water holding capacity equivalent to peat-based potting mixes. We also present results from a laboratory wetting experiment in which we characterized leachate for dissolved organic carbon (DOC) concentration and DOC characteristics using spectral methods (uV-Vis and fluorescence spectroscopy).

Measuring Outcomes for Dysphagia: Validity and Reliability of the European Portuguese Eating Assessment Tool (P-EAT-10).

PubMed

Nogueira, Dália Santos; Ferreira, Pedro Lopes; Reis, Elizabeth Azevedo; Lopes, Inês Sousa

2015-10-01

The purpose of this study was to evaluate the validity and the reliability of the European Portuguese version of the EAT-10 (P-EAT-10). This research was conducted in three phases: (i) cultural and linguistic adaptation; (ii) feasibility and reliability test; and (iii) validity tests. The final sample was formed by a cohort of 520 subjects. The P-EAT-10 index was compared for socio-demographic and clinic variables. It was also compared for both dysphagic and non-dysphagic groups as well as for the results of the 3Oz wst. Lastly, the P-EAT-10 scores were correlated with the EuroQol Group Portuguese EQ-5D index. The Cronbach's α obtained for the P-EAT-10 scale was 0.952 and it remained excellent even if any item was deleted. The item-total and the intraclass correlation coefficients were very good. The P-EAT-10 mean of the non-dysphagic cohort was 0.56 and that of the dysphagic cohort was 14.26, the mean comparison between the 3Oz wst groups and the P-EAT-10 scores were significant. A significant higher perception of QoL was also found among the non-dysphagic subjects. P-EAT-10 is a valid and reliable measure that may be used to document dysphagia which makes it useful both for screening in clinical practice and in research.

Lignin geochemistry of a Late Quaternary sediment core from Lake Washington

NASA Astrophysics Data System (ADS)

Hedges, John I.; Ertel, John R.; Leopold, Estella B.

1982-10-01

Long-term lignin stability and paleovegetation patterns were investigated using CuO oxidation products of sediments from an 11 m core of Late Quaternary sediment collected from the mid-basin of Lake Washington, Washington State. Relatively constant yields of lignin-derived phenols (normalized to organic carbon) from the entire core indicate minimal in situ lignin degradation over the last 13,000 years. Compositional patterns within the phenolic suite and increased corresponding yields from baseextracted sediments indicate that sedimentary lignins are present predominantly as well preserved plant tissue fragments. Abundance patterns of vanillyl, syringyl, and cinnamyl phenols record four distinct sequences within the core characterized by: (a) high concentrations of gymnosperm wood in a basal horizon of glacial flour, 11-10 m; (b) an essentially pure mixture of nonwoody angiosperm tissues in late Pleistocene sediments, 10-8 m; (c) relatively high concentrations of angiosperm woods in the bottom half of a limnic peat sequence deposited approximately 10,000-7,000 years B.P., 8-4 m; and (d) a progressive enrichment in gymnosperm woods at the expense of angiosperm woods over the last 7,000 years in the upper limnic peat, 4-0 m. Vascular plant tissues account for less than half the total sedimentary organic carbon throughout the core.

Geologic and geomorphic controls on the occurrence of fens in the Oregon Cascades and implications for vulnerability and conservation

USGS Publications Warehouse

Aldous, A.; Gannett, Marshall W.; Keith, Mackenzie K.; O'Connor, James E.

2015-01-01

Montane fens are biologically diverse peat-forming wetlands that develop at points of groundwater discharge. To protect these ecosystems, it is critical to understand their locations on the landscape and the hydrogeologic systems that support them. The upper Deschutes Basin has a groundwater flow system that supports baseflow in many rivers, but little is known about the wetland types and groundwater dependence of the thousands of wetlands within the watershed. In 292 randomly selected wetlands, we quantified landscape metrics thought useful for discriminating montane fens from non-peat-forming wetlands. We inspected these wetlands and classified 67 of them as fens. Of the landscape metrics, only geology reliably differentiated fens from other types of wetlands. Nearly all fens develop in low-permeability glacial till found at approximately 1400–1800 m in elevation, and are concentrated in areas mantled by pumice deposits that originated primarily from the eruption of Mt. Mazama approximately 7700 years BP. Stratigraphic and hydrologic factors indicate the fens are supplied by perched aquifers in glacial till, instead of the deeper regional aquifer system. Their hydrogeologic setting makes the fens highly vulnerable to expected changes to recharge associated with climate change, but not to groundwater pumping from the regional aquifer.

Catastrophically buried middle Pennsylvanian sigillaria and calamitean sphenopsids from Indiana, USA: What kind of vegetation was this?

USGS Publications Warehouse

DiMichele, W.A.; Nelson, W.J.; Elrick, S.; Ames, P.R.

2009-01-01

A catastrophically buried stand of calamitean sphenopsids and sigillarian lycopsids is reported from the Middle Pennsylvanian of southwestern Indiana, in the Illinois Basin. The plants were exposed in the highwall of a small surface mine and were rooted in a thin bed of coal (peat), thus representing a flooded and buried swamp surface. Coarse, floodborne silts and sands buried the forest to a depth of 250 linear meters of exposed highwall surface, the vegetation appears to have been a patchwork of calamitean thickets, with stems perhaps as tall as 3-5 m, within which scattered, but much larger, emergent Sigillaria trees grew, possibly reaching heights of 10-15 m. No ground cover was observed, nor were foliage or reproductive organs attributable to the dominant plants found. The growth of this vegetation in a peat-forming swamp indicates conditions of high water availability, likely in a humid, high-rainfall climate. This kind of plant assemblage, however, cannot be characterized as a rain forest, given that it consisted of medium-height thickets of horsetails with scattered, emergent, and polelike, giant lycopsids, thus lacking a closed upper canopy and possibly only partially shading the ground. Copyright ?? 2009, SEPM (Society for Sedimentary Geology).

A model experiment of liquefaction and fluid transport: quantifying the effect of permeability discontinuity

NASA Astrophysics Data System (ADS)

Yasuda, N.; Sumita, I.

2013-12-01

Model experiments of liquefaction of a water-saturated sand (quick sand) is commonly conducted in class and in public. Various phenomena caused by liquefaction are reproduced within a closed bottle containing push-pins (Nohguchi, 2004). Experiments for tilted and layered case have also been conducted (Peacock, 2006). However quantitative measurements of liquid transport in these experiments have rarely been made. Here we show that such measurements are possible by analyzing the video images taken during such experiments. In addition, we show that a simple physical model is capable of explaining the time scales needed to expel the interstitial liquid. An experimental cell (cross section 22.0 mm x 99.4 mm, height 107.6 mm) is filled with a granular matter and water. The lower 33.0 mm consists of a two-layered granular medium, the upper layer consists of fine particles and the lower layer consists of coarse particles, with particle sizes of 0.05 mm and 0.2 mm, respectively. Since permeability depends on the square of the particle size, the upper layer becomes a low-permeability layer. We liquefy the cell by an impulsive vibration and study how the liquid migrates afterwards. We also vary the particle size combinations (upper layer: 0.05-0.15 mm, lower layer: 0.15-0.6 mm) and the thickness ratio of the 2 layers, and study how the time scale of the liquid migration depends on these changeable parameters. In a two-layered medium, we find that the pore water which originated from the bottom layer temporary accumulates at the interface of the two layers, and then ascends through the upper layer in the form of horizontal sheet or vertical channels. We find that these two different discharge styles are controlled by the permeability ratio of the two layers. We study the temporal change of the thicknesses of the two layers and find that there are three stages; 1: the slope of the upper surface is leveled by the impulse, 2: the pore water is discharged from the bottom layer and accumulates at the interface, after which it migrates upwards, 3: water discharge ends, and particles settle. We measured the relaxation time needed for the discharge and compaction to end. Because low-permeability layer inhibits pore water from rising, longer time is needed for a two-layer case compared to the one-layer case. When the particle size of the upper layer is about 1/3 or smaller than that of the lower layer, relaxation time becomes independent of the bottom particle size. We modeled the relaxation time by introducing the effective permeability of two-layered medium, and find that it explains the measurements well. References Nohguchi, Y., 2004, ICTAM04 Proceedings, Warsaw, Poland. Peacock, D. C. P., 2006, J. Geosci.Ed, 54, 550

Upper Ocean Mixing Processes and Circulation in the Arabian Sea during Monsoons using Remote Sensing, Hydrographic Observations and HYCOM Simulations

DTIC Science & Technology

2015-09-30

effecting the salinity of the upper layer and the formation of the barrier layer (BL) within the isothermal layer. The BL in turn controls vertical mixing...daily values over a month with a 1° horizontal resolution [Reynolds et al., 2002]. Daily data (from Coriolis project) and Monthly gridded Argo

Organic matter loss from cultivated peat soils in Sweden

NASA Astrophysics Data System (ADS)

Berglund, Örjan; Berglund, Kerstin

2015-04-01

The degradation of drained peat soils in agricultural use is an underestimated source of loss of organic matter. Oxidation (biological degradation) of agricultural peat soils causes a loss of organic matter (OM) of 11 - 22 t ha-1 y-1 causing a CO2 emission of 20 - 40 t ha-1 y-1. Together with the associated N2O emissions from mineralized N this totals in the EU to about 98.5 Mton CO2 eq per year. Peat soils are very prone to climate change and it is expected that at the end of this century these values are doubled. The degradation products pollute surface waters. Wind erosion of peat soils in arable agriculture can cause losses of 3 - 30 t ha-1 y-1 peat also causing air pollution (fine organic particles). Subsidence rates are 1 - 2 cm per year which leads to deteriorating drainage effect and make peat soils below sea or inland water levels prone to flooding. Flooding agricultural peat soils is in many cases not possible without high costs, high GHG emissions and severe water pollution. Moreover sometimes cultural and historic landscapes are lost and meadow birds areas are lost. In areas where the possibility to regulate the water table is limited the mitigation options are either to increase biomass production that can be used as bioenergy to substitute some fossil fuel, try to slow down the break-down of the peat by different amendments that inhibit microbial activity, or permanent flooding. The negative effects of wind erosion can be mitigated by reducing wind speed or different ways to protect the soil by crops or fiber sheets. In a newly started project in Sweden a typical peat soil with and without amendment of foundry sand is cropped with reed canary grass, tall fescue and timothy to investigate the yield and greenhouse gas emissions from the different crops and how the sand effect the trafficability and GHG emissions.

Contrasting denitrifier communities relate to contrasting N2O emission patterns from acidic peat soils in arctic tundra

PubMed Central

Palmer, Katharina; Biasi, Christina; Horn, Marcus A

2012-01-01

Cryoturbated peat circles (that is, bare surface soil mixed by frost action; pH 3–4) in the Russian discontinuous permafrost tundra are nitrate-rich ‘hotspots' of nitrous oxide (N2O) emissions in arctic ecosystems, whereas adjacent unturbated peat areas are not. N2O was produced and subsequently consumed at pH 4 in unsupplemented anoxic microcosms with cryoturbated but not in those with unturbated peat soil. Nitrate, nitrite and acetylene stimulated net N2O production of both soils in anoxic microcosms, indicating denitrification as the source of N2O. Up to 500 and 10 μ nitrate stimulated denitrification in cryoturbated and unturbated peat soils, respectively. Apparent maximal reaction velocities of nitrite-dependent denitrification were 28 and 18 nmol N2O gDW−1 h−1, for cryoturbated and unturbated peat soils, respectively. Barcoded amplicon pyrosequencing of narG, nirK/nirS and nosZ (encoding nitrate, nitrite and N2O reductases, respectively) yielded ≈49 000 quality-filtered sequences with an average sequence length of 444 bp. Up to 19 species-level operational taxonomic units were detected per soil and gene, many of which were distantly related to cultured denitrifiers or environmental sequences. Denitrification-associated gene diversity in cryoturbated and in unturbated peat soils differed. Quantitative PCR (inhibition-corrected per DNA extract) revealed higher copy numbers of narG in cryoturbated than in unturbated peat soil. Copy numbers of nirS were up to 1000 × higher than those of nirK in both soils, and nirS nirK−1 copy number ratios in cryoturbated and unturbated peat soils differed. The collective data indicate that the contrasting N2O emission patterns of cryoturbated and unturbated peat soils are associated with contrasting denitrifier communities. PMID:22134649

Diagenetic Layers in the Upper Walls of Valles Marineris, Mars: Evidence for Drastic Climate Change Since the Mid-Hesperian

NASA Technical Reports Server (NTRS)

Treiman, Allan H.; Fuks, Kelly H.; Murchie, Scott

1995-01-01

A packet of relatively resistant layers, totaling approx. 400 m thickness, is present at the tops of the chasma walls throughout Valles Marineris. The packet consists of an upper dark layer (approx. 50 m thick), a central bright layer (approx. 250 m thick), and a lower dark layer (approx. 100 m thick). The packet appears continuous and of nearly constant thickness and depth below ground surface over the whole Valles system (4000 km E-W, 800 km N-S), independent of elevation (3-10 km) and age of plateau surface (Noachian through upper Hesperian). The packet continues undisturbed beneath the boundary between surface units of Noachian and Hesperian ages, and continues undisturbed beneath impact craters transected by chasma walls. These attributes are not consistent with layer formation by volcanic or sedimentary deposition, and are consistent with layer formation in situ, i.e., by diagenesis, during or after upper Hesperian time. Diagenesis seems to require the action of aqueous solutions in the near subsurface, which are not now stable in the Valles Marineris area. To permit the stability of aqueous solutions, Mars must have had a fairly dense atmosphere, greater than or equal to 1 bar CO2, when the layers formed. Obliquity variations appear to be incapable of producing such a massive atmosphere so late in Mars' history.

Wavelength dependence of polarization. XXXX. Venus upper atmosphere aerosol layers from polarimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santer, R.; Dollfus, A.

1980-06-01

Previous photometric and polarimetric observations of Venus have indicated the presence of a thin layer of small particles above the usual cloud layers. We sensed some characteristics of this upper layer on the basis of the Meudon and Pic-du-Midi regional polarization survey, covering from 1950 to 1972. Optical thicknesses of the order of several percent with particle radii of around 0.2 ..mu..m are indicated. The refraction index is not known. Although this layer is apparently globally permanent, variations occur regionally and with time.

Mycobacterium avium subsp. hominissuis infection in swine associated with peat used for bedding.

PubMed

Johansen, Tone Bjordal; Agdestein, Angelika; Lium, Bjørn; Jørgensen, Anne; Djønne, Berit

2014-01-01

Mycobacterium avium subsp. hominissuis is an environmental bacterium causing opportunistic infections in swine, resulting in economic losses. Additionally, the zoonotic aspect of such infections is of concern. In the southeastern region of Norway in 2009 and 2010, an increase in condemnation of pig carcasses with tuberculous lesions was seen at the meat inspection. The use of peat as bedding in the herds was suspected to be a common factor, and a project examining pigs and environmental samples from the herds was initiated. Lesions detected at meat inspection in pigs originating from 15 herds were sampled. Environmental samples including peat from six of the herds and from three peat production facilities were additionally collected. Samples were analysed by culture and isolates genotyped by MLVA analysis. Mycobacterium avium subsp. hominissuis was detected in 35 out of 46 pigs, in 16 out of 20 samples of peat, and in one sample of sawdust. MLVA analysis demonstrated identical isolates from peat and pigs within the same farms. Polyclonal infection was demonstrated by analysis of multiple isolates from the same pig. To conclude, the increase in condemnation of porcine carcasses at slaughter due to mycobacteriosis seemed to be related to untreated peat used as bedding.

Mycobacterium avium subsp. hominissuis Infection in Swine Associated with Peat Used for Bedding

PubMed Central

Johansen, Tone Bjordal; Lium, Bjørn; Jørgensen, Anne; Djønne, Berit

2014-01-01

Mycobacterium avium subsp. hominissuis is an environmental bacterium causing opportunistic infections in swine, resulting in economic losses. Additionally, the zoonotic aspect of such infections is of concern. In the southeastern region of Norway in 2009 and 2010, an increase in condemnation of pig carcasses with tuberculous lesions was seen at the meat inspection. The use of peat as bedding in the herds was suspected to be a common factor, and a project examining pigs and environmental samples from the herds was initiated. Lesions detected at meat inspection in pigs originating from 15 herds were sampled. Environmental samples including peat from six of the herds and from three peat production facilities were additionally collected. Samples were analysed by culture and isolates genotyped by MLVA analysis. Mycobacterium avium subsp. hominissuis was detected in 35 out of 46 pigs, in 16 out of 20 samples of peat, and in one sample of sawdust. MLVA analysis demonstrated identical isolates from peat and pigs within the same farms. Polyclonal infection was demonstrated by analysis of multiple isolates from the same pig. To conclude, the increase in condemnation of porcine carcasses at slaughter due to mycobacteriosis seemed to be related to untreated peat used as bedding. PMID:25431762

Rice husk ash (RHA) as a partial cement replacement in modifying peat soil properties

NASA Astrophysics Data System (ADS)

Daud, Nik Norsyahariati Nik; Daud, Mohd Nazrin Mohd; Muhammed, Abubakar Sadiq

2018-02-01

This paper describes the effect of rice husk ash (RHA) and ordinary Portland cement (OPC) as a potential binder for modifying the properties of peat soil. The amounts RHA and OPC added to the peat soil sample, as percentage of the dry soil mass were in the range of 10-15% and 15%, respectively. Observations were made for the changes in the properties of the soil such as maximum dry density (MDD), optimum moisture content (OMC) and shear strength. Scanning Electron Micrograph-Energy Dispersive X-Ray (SEM-EDX) test were also conducted to observe the microstructure of treated and untreated peat soil. The results show that the modified soil of MDD and OMC values are increased due to the increment amount of binder material. Shear strength values of modified peat showing a good result by assuming that it is relative to the formation of major reaction products such as calcium silicate hydrate (C-S-H). The presence of C-S-H formation is indicated by the results produced from microstructural analysis of peat before and after modification process. This depicts the potential usage of RHA as a partial cement replacement in peat soil which is also improving its engineering properties.

Effect of Peat on Physicomechanical Properties of Cemented Brick

PubMed Central

Hashim, Roslan; Kurnia, Ryan

2014-01-01

The popularity of low cost, lightweight, and environmentally affable masonry unit in building industry carries the need to investigate more flexible and adaptable brick component as well as to retain the requirements confirmed in building standards. In this study, potential use of local materials used as lightweight building materials in solving the economic problems of housing has been investigated. Experimental studies on peat added bricks have been carried out. It demonstrates the physicomechanical properties of bricks and investigates the influence of peat, sand, and cement solid bricks to the role of various types of constructional applications. The achieved compressive strength, spitting strength, flexural strength, unit weight, and ultrasonic pulse velocity are significantly reduced and the water absorption is increased with percentage wise replacement of peat as aggregate in the samples. The maximum 20% of (% mass) peat content meets the requirements of relevant well-known international standards. The experimental values illustrate that, the 44% volumetric replacement with peat did not exhibit any sudden brittle fracture even beyond the ultimate loads and a comparatively smooth surface is found. The application of peat as efficient brick substance shows a potential to be used for wall and a viable solution in the economic buildings design. PMID:24982941

Ground-water hydrology and simulation of ground-water flow at Operable Unit 3 and surrounding region, U.S. Naval Air Station, Jacksonville, Florida

USGS Publications Warehouse

Davis, J.H.

1998-01-01

The Naval Air Station, Jacksonville (herein referred to as the Station), occupies 3,800 acres adjacent to the St. Johns River in Duval County, Florida. Operable Unit 3 (OU3) occupies 134 acres on the eastern side of the Station and has been used for industrial and commercial purposes since World War II. Ground water contaminated by chlorinated organic compounds has been detected in the surficial aquifer at OU3. The U.S. Navy and U.S. Geological Survey (USGS) conducted a cooperative hydrologic study to evaluate the potential for ground water discharge to the neighboring St. Johns River. A ground-water flow model, previously developed for the area, was recalibrated for use in this study. At the Station, the surficial aquifer is exposed at land surface and forms the uppermost permeable unit. The aquifer ranges in thickness from 30 to 100 feet and consists of unconsolidated silty sands interbedded with local beds of clay. The low-permeability clays of the Hawthorn Group form the base of the aquifer. The USGS previously conducted a ground-water investigation at the Station that included the development and calibration of a 1-layer regional ground-water flow model. For this investigation, the regional model was recalibrated using additional data collected after the original calibration. The recalibrated model was then used to establish the boundaries for a smaller subregional model roughly centered on OU3. Within the subregional model, the surficial aquifer is composed of distinct upper and intermediate layers. The upper layer extends from land surface to a depth of approximately 15 feet below sea level; the intermediate layer extends from the upper layer down to the top of the Hawthorn Group. In the northern and central parts of OU3, the upper and intermediate layers are separated by a low-permeability clay layer. Horizontal hydraulic conductivities in the upper layer, determined from aquifer tests, range from 0.19 to 3.8 feet per day. The horizontal hydraulic conductivity in the intermediate layer, determined from one aquifer test, is 20 feet per day. An extensive stormwater drainage system is present at OU3 and the surrounding area. Some of the stormwater drains have been documented to be draining ground water from the upper layer of the surficial aquifer, whereas other drains are only suspected to be draining ground water. The subregional model contained 78 rows and 148 columns of square model cells that were 100 feet on each side. Vertically, the surficial aquifer was divided into two layers; layer 1 represented the upper layer and layer 2 represented the intermediate layer. Steady-state ground-water flow conditions were assumed. The model was calibrated to head data collected on October 29 and 30, 1996. After calibration, the model matched all 67 measured heads to within the calibration criterion of 1 foot; and 48 of 67 simulated heads (72 percent) were within 0.5 foot. Model simulated recharge rates ranged from 0.4 inch per year in areas that were largely paved to 13.0 inches per year in irrigated areas. Simulated hydraulic conductivities in the upper layer at OU3 ranged from 0.5 foot per day in the north to 1.0 foot per day in the south. Simulated vertical leakance between the upper and intermediate layers ranged from 1.0x10-6 per day in an area with low-permeability clays to 4.3x10-2 per day in an area that had been dredged. Simulated transmissivities in the intermediate layer ranged from 25 feet squared per day in an area of low-permeability channel-fill deposits to a high of 1,200 feet squared per day in areas covering most of OU3. Simulated riverbed conductances ranged from 4 to 60 feet squared per day and simulated bottom conductances of leaking stormwater drains ranged from 5 to 20 feet squared per day. The direction and velocity of ground-water flow was determined using particle-tracking techniques. Ground-water flow in the upper layer was generally eastward toward the St. Johns River. However, leaking stormwat

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

NASA Astrophysics Data System (ADS)

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

2012-04-01

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

Production of fuel ethanol from cellulosic peat for future transportation systems.

DOT National Transportation Integrated Search

2007-12-01

The production of bioethanol from peat is proposed. A search of the available : literature yields no prior information on the use of peat as a carbon source for : bioethanol. This proposal addresses the production in the most cost-effective manner : ...

SPRUCE S1 Bog Vegetation Survey and Peat Depth Data: 2009

DOE Data Explorer

Hanson, P. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A

2009-12-31

This data set reports the results of a field survey of the S1 Bog to characterize the vegetation and to determine peat depth. The survey was conducted on September 21 and 22, 2009. The initial survey of vegetation and peat depth characteristics of the target bog was conducted to evaluate the logical locations for installing replicated experimental blocks for SPRUCE. The goal was to identify multiple locations of uniform aboveground vegetation and belowground peat depth for positioning experimental units within the bog.

Altered peat hydrophysical properties following drainage and wildfire increases peatland vulnerability to ecosystem regime shift

NASA Astrophysics Data System (ADS)

Waddington, James; Kettridge, Nick; Sherwood, James; Granath, Gustaf

2015-04-01

Northern peatlands represent a globally significant carbon reservoir, composed largely of legacy carbon which is no longer part of the active carbon cycle. However, it is unclear whether this legacy carbon is vulnerable as a result of enhanced peat smouldering and combustion under the moderate drying conditions predicted for northern peatlands as a result of climate change and/or disturbance from forestry, mining, and associated transport development. A significant loss in legacy carbon as a result of wildfire has already been observed in smaller tropical peatlands where deep peat soils have been destabilized due to severe drainage and a shift in vegetation. Capitalizing on a unique long-term experiment, we quantify the post-wildfire recovery of a northern peatland several decades post drainage. We show that the moderate drop in water table position predicted for most northern regions triggers a shift in vegetation composition, previously observed within only severely disturbed tropical peatlands, when accompanied by wildfire. The combined impact of moderate drainage followed by wildfire resulted in a shift of the peat surface down the peat profile, exposing denser peat at the surface. In undisturbed northern peatlands where depth of burn is typically low, low-density near-surface peats help regulate water-table position and near-surface moisture availability post-fire, both of which are favourable to Sphagnum recolonization. As a result of drainage and fire at the study site, the self-regulating properties of the low-density Sphagnum surface were lost. We demonstrate that changes in peat hydrophysical properties increased hydrological limitations to Sphagnum recovery leading to the conversion to a non-carbon accumulating shrub-grass ecosystem. This new ecosystem is likely to experience a low intensity, high frequency wildfire regime, which will further deplete the legacy carbon stored in the peat.

Inorganic geochemistry of domed peat in Indonesia and its implication for the origin of mineral matter in coal

USGS Publications Warehouse

Neuzil, Sandra G.; Supardi,; Cecil, C. Blaine; Kane, Jean S.; Soedjono, Kadar

1993-01-01

The inorganic geochemistry of three domed ombrogenous peat deposits in Riau and West Kalimantan provinces, Indonesia, was investigated as a possible modern analogue for certain types of low-ash, low-sulfur coal. Mineral matter entering the deposits is apparently limited to small amounts from the allogenic sources of dryfall, rainfall, and diffusion from substrate pore water. In the low-ash peat in the interior of the deposits, a large portion of the mineral matter is authigenic and has been mobilized and stabilized by hydrological, chemical, and biological processes and conditions.Ash yield and sulfur content are low through most of the peat deposits and average 1.1% and 0.14%, respectively, on a moisture-free basis. Ash and sulfur contents only exceed 5% and 0.3%, respectively, near the base of the deposits, with maximum concentrations of 19.9% ash and 0.56% sulfur. Peat water in all three deposits has a low pH, about 4 units, and low dissolved cation concentration, averaging 14 ppm. Near the base, in the geographic interior of each peat deposit, pH is about two units higher and dissolved cation concentration averages 110 ppm. Relative concentrations of the inorganic constituents vary, resulting in chemical facies in the peat. In general, Si, Al, and Fe are the abundant inorganic constituents, although Mg, Ca, and Na dominate in the middle horizon in the geographic interior of coastal peat deposits.The composition of the three deposits reported in this paper indicates that domed ombrogenous peat deposits will result in low ash and sulfur coal, probably less than 10% ash and 1% sulfur, even if marine rocks are laterally and vertically adjacent to the coal.

Heterotrophic respiration in drained tropical peat temperatures influenced by shading gradient

NASA Astrophysics Data System (ADS)

Jauhiainen, Jyrki; Kerojoki, Otto; Silvennoinen, Hanna; Limin, Suwido; Vasander, Harri

2015-04-01

Lowland peatlands in Southeast Asia constitute a highly concentrated carbon (C) pool of global significance. These peatlands have formed over periods of several millennia by forest vegetation tolerant to flooding and poor substrates. Uncontrollable drainage and reoccurring wild fires in lack of management after removal of forest cover has impaired the C-storing functions in large reclaimed areas. Intergovernmental Panel on Climate Change (IPCC) reporting sees drained tropical organic soils as one of the largest greenhouse gas emissions releasing terrestrial systems. Vast areas of deforested tropical peatlands do not receive noteworthy shading by vegetation, which increases the amount of solar radiation reaching the peat surface. We studied heterotrophic carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) fluxes in tropical peat in conditions, where; (i) peat temperatures were modified by artificial shading (no shade, 28%, 51% and 90% from the full sun exposure), (ii) root respiration was minimized, (iii) nutrient availability for peat decomposer community was changed (NPK fertilization of 0 and 313 kg ha-1). The experiment was repeated at two over 20 years ago drained fallow agricultural- and degraded sites in Central Kalimantan, Indonesia. Enhanced shading created a lasting decrease in peat temperatures, and decreased diurnal temperature fluctuations, in comparison to less shaded plots. The largest peat temperature difference was between the unshaded and 90% shaded peat surface, where the average temperatures within the topmost 50-cm peat profile differed 3 °C, and diurnal temperatures at 5 cm depth varied up to 4.2 °C in the unshaded and 0.4 °C in the 90% shaded conditions. Highest impacts on the heterotrophic CO2 fluxes caused by the treatments were on agricultural land, where 90% shading from the full exposure resulted in a 33% lower CO2 emission average on the unfertilised plots and a 66% lower emission average on the fertilised plots. Correlation between peat temperature and CO2 flux suggested an approximately 8% (unfertilised) and 25% (fertilised) emissions change for each 1 °C temperature change at 5 cm depth on the agricultural land. CO2 flux responses to the treatments remained low or were inconsistent over the peat temperature range.. Fertilised conditions negatively correlated with N2O efflux with increases in temperature, suggesting a 12-36% lower efflux for each 1 °C increase in peat temperature (at 5 cm depth) at the sites. Despite the apparently similar landscapes of fallow agricultural land and degraded peatland sites, the differences in greenhouse gas dynamics are expected to be an outcome of the long-term management differences. Based on the results it is possible to seek management practices that prolong timespan for using drained tropical peat for cultivation, simultaneously reduce negative climate impacts created from peat substrate carbon loss, and also improve greenhouse gas monitoring techniques at field.

The pectinate zone is stiff and the arcuate zone determines passive basilar membrane mechanics in the gerbil

NASA Astrophysics Data System (ADS)

Xia, Hongyi; Steele, Charles R.; Puria, Sunil

2018-05-01

The gerbil basilar membrane (BM) differs from other mammalian BMs in that the lower collagen-fiber layer of the pectinate zone (PZ) forms an arch, the upper fiber layer is flat, and ground substance separates the two layers. The role of this arch has been unknown, but can be elucidated by models. In the standard simple beam model (SBM), the upper and lower collagen-fiber layers of the BM are represented as a single layer in both the PZ and the arcuate zone (AZ). In our new arch-beam model (ABM), the upper fiber layer is flat, the lower layer forms an arch in the PZ, and the two layers combine to form the flat portion of the BM in the AZ. This design is incorporated into a 3D finite-element tapered-box model of the cochlea with viscous fluid. We find in the model that the PZ rotates as a rigid body, so its specific properties have little influence, while the AZ thickness and collagen volume fraction primarily determine passive BM mechanics.

Streambed peat lenses as redox-reactivity hotspots in lowland river hyporheic zones

NASA Astrophysics Data System (ADS)

Naden, Emma; Krause, Stefan; Cassidy, Nigel

2010-05-01

Hyporheic zones, as the direct interfaces between aquifers and rivers, are often characterised by increased redox reactivity and chemical transformation capacity. Depending on redox conditions and reaction types, hyporheic mixing of groundwater and surface water can lead to either attenuation or enrichment of pollutants or nutrients with diametrical implications for in-stream and aquifer hydro-ecological status. This study combines geophysical methods with distributed temperature sensor networks and nested multi-level sampling and analysis of hyporheic redox conditions and nutrient concentrations to investigate the reactive transport of nitrate at the aquifer-river interface of a UK lowland river. In stream Electric Resistivity Tomography and Ground Penetrating Radar (including core based ground truthing) have been applied to map the complex spatial patterns of highly conductive sandy and gravely sediments in contrast to semi-confining, low conductivity peat lenses which have been found to be characteristic for most lowland rivers. Reach scale (1km) spatial patterns and temporal dynamics of aquifer-river exchange have been identified by heat tracer experiments based on fibre-optical Distributed Temperature Sensing techniques combined with vertical thermocouple-arrays for tracing hyporheic flow paths. Spatial patterns of hyporheic redox conditions, dissolved oxygen (DO) and organic carbon (DOC) content as well as concentrations of major anions have been monitored in 48 nested multi-level mini-piezometers. Our investigations indicate that streambed temperature patterns were dominantly controlled by groundwater up-welling, causing cold spots in sandy and gravely sediments with high up-welling rates and low hyporheic residence times and warmer areas at the streambed surface where groundwater - surface water exchange was inhibited by streambed peat lenses. The flow-inhibiting peat structures have been found to cause semi-confined conditions in the up-welling groundwater, resulting in long residence times and increased redox-reactivity. Anoxic conditions and high DOC contents combined with long residence times underneath peat layers cause highly efficient denitrification rates, reducing nitrate concentrations from > 50mg/l to below the level of detection. In contrast, sandy and gravely areas of fast groundwater up-welling where characterized by only marginal changes in nitrate concentrations. The investigations lead to the development of a conceptual model of aquifer - river exchange and hyporheic reactivity in lowland rivers including temperature traceable hyporheic reactivity hotspots with high denitrification potential. The results for this exemplary field site highlight the substantial nutrient attenuation capacity of hyporheic zones at lowland rivers and emphasize the great importance of their consideration for river restoration programs and the assessment of water quality and ecological status.

Foam concrete of increased strength with the thermomodified peat additives

NASA Astrophysics Data System (ADS)

Kudyakov, A. I.; Kopanitsa, N. O.; Sarkisov, Ju S.; Kasatkina, A. V.; Prischepa, I. A.

2015-01-01

The paper presents the results of research of foam concrete with thermomodified peat additives. The aim of the research was to study the effect of modifying additives on cement stone and foam concrete properties. Peat additives are prepared by heat treatment of peat at 600 °C. Two approaches of obtaining additives are examined: in condition of open air access (TMT-600) and in condition of limited air access (TMT-600-k). Compressive strength of a cement stone with modifiers found to be increased by 28.9 - 65.2%. Introducing peat modifiers into foam concrete mix leads to increase of compressive strength by 44-57% at 28- day age and heat conductivity of foam concrete decreases by 0.089 W/(m·°C).

Alfred P. Dachnowski and the scientific study of peats

USGS Publications Warehouse

Landa, E.R.; Cohen, K.M.

2011-01-01

Botanist Alfred Paul Dachnowski (1875–1949) was a major contributor to efforts at mapping organic soils in the United States during the early 20th century. He began his career at The Ohio State University, and spent most of his professional life at the U.S. Department of Agriculture in Washington, DC. His work spanned a diversity of topics, including bog ecology and the ecosystem services provided by wetlands, the mapping and chemical characterization of peat, and the commercial applications of peat. We present a biography and overview of his work. Dachnowski is best known today for the peat sampler that bears his name. The details of its operation are described here, and its place in modern peat studies is discussed.

Holocene Development of Subarctic Permafrost Peatlands in Finnmark, Northern Norway

NASA Astrophysics Data System (ADS)

Sannel, B.; Axelsson, P.; Kjellman, S.; Etzelmuller, B.; Westermann, S.

2017-12-01

Subarctic permafrost peatlands have acted as important carbon sinks throughout the Holocene. An improved knowledge of peat properties and sensitivity to past climate changes in these environments can help us better predict future responses under warmer climatic conditions, and associated permafrost carbon feedbacks. In this study analyses of plant macrofossils, bulk density, organic, carbon and nitrogen content, and AMS radiocarbon dating have been performed for four profiles collected from peat plateaus in Finnmark, northern Norway. Preliminary results suggest that peatland development started around 9800-9200 cal yr BP at the two continental sites, Suossjavri and Iskoras. Here, the long-term net carbon accumulation rates are around 12-17 gC m-2 yr-1, and the total carbon storage c. 113-156 kgC m-2. The other two sites, Lakselv and Karlebotn, are located in maritime settings close to the coast where there has been a time lag between deglaciation of the Fennoscandian Ice Sheet and emergence of land by isostatic uplift. At these sites peatland inception begun around 6200-5200 cal yr BP, and the carbon accumulation rates are c. 7-12 gC m-2 yr-1. Because of a shorter time period available for peat accumulation the carbon storage at these sites is lower, around 56-64 kgC m-2. All four peatlands developed as wet fens, and have remained permafrost-free throughout most of the Holocene. Permafrost aggradation, causing frost heave and a shift in the vegetation assemblage from wet fen to dry bog species, probably did not occur until during the onset of the Little Ice Age c. 1000-800 cal yr BP (at Iskoras and Karlebotn) or even later, around 100 cal yr BP (at Suossjavri and Lakselv). If the permafrost thaws in a future warmer climate, the carbon that has been stored in the frozen peat since the Little Ice Age can become available for decomposition and be emitted to the atmosphere either as carbon dioxide from expanding active layers or as methane from thermokarst lakes and fens.

Volatile and semivolatile organic compounds in laboratory peat fire emissions

EPA Science Inventory

Speciated volatile organic compounds (VOCs) and organic fine particulate matter (PM2.5) mass emission factors were determined from laboratory peat fire experiments. Peat samples originated from two wildlife reserves located near the coast of North Carolina, U.S. Gas and particula...

The Challenge of Peat Substitution in Organic Seedling Production: Optimization of Growing Media Formulation through Mixture Design and Response Surface Analysis

PubMed Central

Ceglie, Francesco Giovanni; Bustamante, Maria Angeles; Ben Amara, Mouna; Tittarelli, Fabio

2015-01-01

Peat replacement is an increasing demand in containerized and transplant production, due to the environmental constraints associated to peat use. However, despite the wide information concerning the use of alternative materials as substrates, it is very complex to establish the best materials and mixtures. This work evaluates the use of mixture design and surface response methodology in a peat substitution experiment using two alternative materials (green compost and palm fibre trunk waste) for transplant production of tomato (Lycopersicon esculentum Mill.); melon, (Cucumis melo L.); and lettuce (Lactuca sativa L.) in organic farming conditions. In general, the substrates showed suitable properties for their use in seedling production, showing the best plant response the mixture of 20% green compost, 39% palm fibre and 31% peat. The mixture design and applied response surface methodology has shown to be an useful approach to optimize substrate formulations in peat substitution experiments to standardize plant responses. PMID:26070163

Features of the Functioning Bacterial Ecosystems in the Antarctic

NASA Astrophysics Data System (ADS)

Yakushev, A. V.; Churilin, N.; Soina, V. S.; Vorobyova, E. A.; Mergelov, N. S.

2014-10-01

Studies of bacterial communities in the samples of Antarctic soils by different methods showed that, both in liquid soil suspensions and in situ, microbial complexes are functioning presumably by forming biofilms -- the phenomenon that is more expressed in such habitat than in soils of temperate zones. Functional (trophic) diversity and physiological state of hydrolytic bacteria was studied in the samples at the upper layer (0-2 cm) of gravel pavement with algae, in the underlying peat horizon (2-4 cm) with inclusions of dead biomass and its underlying mineral horizon (4-10 cm) with signs of fungal mycelium. The investigated samples of Antarctic soils revealed different trophic diversity and the maximum specific growth rate on mineral medium with different biopolymers as the sole carbon source (starch, chitin, pectin, xylan, dextran-500, tween-20, casein); this can testify to differences in the physiological state of hydrolytic bacteria in various soil horizons and their readiness for growth. The most remarkable characteristics of the studied Antarctic soil as compared to the soils of temperate zone, was the unusual ability of hydrolytic community to consume chitin in the mineral horizon; this can be explained by the presence of fungal mycelium. Also, an almost complete lack in consumption of tween-20 (a water-soluble analogue of fat) by bacterial community of Arctic soil horizons are not explained and needs further verification. The higher functional diversity was detected in the upper horizon of the gravel pavement, which "protects" microorganisms from exposure to extreme temperatures, UV radiation, and desiccation, but the maximum specific growth rate was higher in the lower mineral horizon; this can be explained by the specificity of bacterial colonizing processes and unique formation of Antarctic soil microprofiles in the Larsemann oasis. The obtained data indicate a specific environmental strategy in the samples of Antarctic soils: development in lower mineral horizons of microorganisms with a high metabolic readiness to life revival and high maximum growth rate.

Study Of Functioning of Bacterial Complexes in East Antarctic Soils

NASA Astrophysics Data System (ADS)

Yakushev, A. V.; Churilin, N. A.

2014-11-01

Studies of bacterial communities in the samples of Antarctic soils by different methods showed that, both in liquid soil suspensions and in situ, microbial complexes are functioning presumably by forming biofilms - the phenomenon that is more expressed in such habitat than in soils of temperate zones. Functional (trophic) diversity and physiological state of hydrolytic bacteria was studied in the samples at the upper layer (0-2 cm) of gravel pavement with algae, in the underlying peat horizon (2-4 cm) with inclusions of dead biomass and its underlying mineral horizon (4-10 cm) with signs of fungal mycelium. The investigated samples of Antarctic soils revealed different trophic diversity and the maximum specific growth rate on mineral medium with different biopolymers as the sole carbon source (starch, chitin, pectin, xylan, dextran-500, tween-20, casein); this can testify to differences in the physiological state of hydrolytic bacteria in various soil horizons and their readiness for growth. The most remarkable characteristics of the studied Antarctic soil as compared to the soils of temperate zone, was the unusual ability of hydrolytic community to consume chitin in the mineral horizon; this can be explained by the presence of fungal mycelium. Also, an almost complete lack in consumption of tween-20 (a water-soluble analogue of fat) by bacterial community of Arctic soil horizons are not explained and needs further verification. The higher functional diversity was detected in the upper horizon of the gravel pavement, which "protects" microorganisms from exposure to extreme temperatures, UV radiation, and desiccation, but the maximum specific growth rate was higher in the lower mineral horizon; this can be explained by the specificity of bacterial colonizing processes and unique formation of Antarctic soil microprofiles in the Larsemann oasis. The obtained data indicate a specific environmental strategy in the samples of Antarctic soils: development in lower mineral horizons of microorganisms with a high metabolic readiness to life revival and high maximum growth rate.

Global distribution of soil organic carbon - Part 1: Masses and frequency distributions of SOC stocks for the tropics, permafrost regions, wetlands, and the world

NASA Astrophysics Data System (ADS)

Köchy, M.; Hiederer, R.; Freibauer, A.

2015-04-01

The global soil organic carbon (SOC) mass is relevant for the carbon cycle budget and thus atmospheric carbon concentrations. We review current estimates of SOC stocks and mass (stock × area) in wetlands, permafrost and tropical regions and the world in the upper 1 m of soil. The Harmonized World Soil Database (HWSD) v.1.2 provides one of the most recent and coherent global data sets of SOC, giving a total mass of 2476 Pg when using the original values for bulk density. Adjusting the HWSD's bulk density (BD) of soil high in organic carbon results in a mass of 1230 Pg, and additionally setting the BD of Histosols to 0.1 g cm-3 (typical of peat soils), results in a mass of 1062 Pg. The uncertainty in BD of Histosols alone introduces a range of -56 to +180 Pg C into the estimate of global SOC mass in the top 1 m, larger than estimates of global soil respiration. We report the spatial distribution of SOC stocks per 0.5 arcminutes; the areal masses of SOC; and the quantiles of SOC stocks by continents, wetland types, and permafrost types. Depending on the definition of "wetland", wetland soils contain between 82 and 158 Pg SOC. With more detailed estimates for permafrost from the Northern Circumpolar Soil Carbon Database (496 Pg SOC) and tropical peatland carbon incorporated, global soils contain 1325 Pg SOC in the upper 1 m, including 421 Pg in tropical soils, whereof 40 Pg occurs in tropical wetlands. Global SOC amounts to just under 3000 Pg when estimates for deeper soil layers are included. Variability in estimates is due to variation in definitions of soil units, differences in soil property databases, scarcity of information about soil carbon at depths > 1 m in peatlands, and variation in definitions of "peatland".

Geological Evidence for the Destruction of Shinmachi, Hawaii, by the 1946 Aleutian and 1960 Chile Tsunamis?

NASA Astrophysics Data System (ADS)

Chague-Goff, C.; Goto, K.; Goff, J. R.; Gadd, P.; Dudley, W. C.; Sugawara, D.; Nakamura, N.

2016-12-01

Around 1900, Japanese workers brought to Big Island, Hawaii, to work on the sugar plantations, established the Shinmachi (`New Town') community on low-lying land on Hilo's waterfront. Although Shinmachi was obliterated by the 1946 Aleutian tsunami, it was rebuilt, only to be totally destroyed again by the 1960 Chile tsunami. Shinmachi was never rebuilt and the site is now part of the Wailoa State Park. Short cores were collected throughout the park in an attempt to recover the geological evidence of these two tsunamis. Two anomalous layers, a lower sand (Unit 1) and an upper fining upward fine sand to silt (Unit 2) intercalated within soil and peat and exhibiting sharp lower and upper contacts, were recorded at only a few locations, probably reflecting, at least partly, the effect of anthropogenic disturbance and a limited amount of accommodation space on recent Holocene lava flows. One core was analysed by ITRAX core scanner equipped with a magnetic susceptibility (MS) meter. Unit 1 exhibits high MS associated with high Fe, Mn and Rb counts, but low Si and K counts, reflecting the volcanic composition of the material, and probably an older flooding event from the river. Unit 2 on the other hand is characterised by a different suite of elements, including Si, K, Ti, Mn, Fe, Ca, Sr, Zr and As. These most likely represent the mineralogical and chemical composition of shallow marine sediments from Hilo Bay and/or brackish sediments from Wailoa River estuary. High concentrations of As in particular have previously been reported in sediments from Hilo Bay and Wailoa River estuary and attributed to the release of arsenic trioxide by a canec manufacturing plant between 1932-1963. In this study, As was absent below Unit 2, and can thus be used as chronological control. Unit 2 therefore most likely represents the 1946 tsunami deposit. There was no clear evidence for the 1960 tsunami, probably reflecting the limited amount of accommodation space in the area.

Using natural distributions of short-lived radium isotopes to quantify groundwater discharge and recharge

USGS Publications Warehouse

Krest, J.M.; Harvey, J.W.

2003-01-01

Radium activity in pore water of wetland sediments often differs from the amount expected from local production, decay, and exchange with solid phases. This disequilibrium results from vertical transport of radium with groundwater that flows between the underlying aquifer and surface water. In situations where groundwater recharge or discharge is significant, the rate of vertical water flow through wetland sediment can be determined from the radium disequilibrium by a combined model of transport, production, decay, and exchange with solid phases. We have developed and tested this technique at three sites in the freshwater portion of the Everglades by quantifying vertical advective velocities in areas with persistent groundwater recharge or discharge and estimating a coefficient of dispersion at a site that is subject to reversals between recharge and discharge. Groundwater velocities (v) were determined to be between 0 and -0.5 cm d-1 for a recharge site and 1.5 ?? 0.4 cm d-1 for a discharge site near Levee 39 in the Everglades. Strong gradients in 223Ra and 224Ra usually occurred at the base of the peat layer, which avoided the problems of other tracers (e.g., chloride) for which greatest sensitivity occurs near the peat surface - a zone readily disturbed by processes unrelated to groundwater flow. This technique should be easily applicable to any wetland system with different production rates of these isotopes in distinct sedimentary layers or surface water. The approach is most straightforward in systems where constant pore-water ionic strength can be assumed, simplifying the modeling of radium exchange.

Impact of long-term wetting on belowground respiration and methanogenesis in Luther Bog, Ontario

NASA Astrophysics Data System (ADS)

Goebel, Marie; Blodau, Christian

2016-04-01

Peatlands play a major role in the global carbon cycle. They store one-third of total world soil carbon, sequester carbon dioxide (CO2) and release CO2 and methane (CH4). Climate and land-use change are predicted to cause either wetter winters and wetter summers or wetter winters and drier summers in the area where northern peatlands are located. Feedback on processes in the peat is poorly understood on the time scale of decades. In this study, we investigated impacts of long-term wetting and long-term fluctuating water table on potential CO2 and CH4 production rates and organic matter quality of the fractions bulk peat, pore water and leachate. Bulk peat potential CO2 production rates of 2.38 to 25.55 μmol g-1 d-1 (aerobic) and 1.53 to 7.33 μmol g-1 d-1 (anaerobic) decreased with depth along with a decrease in organic matter quality. Potential CH4 production rates (0.002 to 2.60 μmol g-1 d-1) increased with anaerobic conditions and a lack of electron acceptors rather than being dependent on the availability of labile organic matter. This pattern was less evident in solute fraction samples where labile compounds in top layers were probably either too labile to be detected or water movement obscured differences between depths. Bulk peat potential anaerobic CO2 and CH4 production increased through long-term wetting. As wetting did not change organic matter quality or aerobic production rates, increased anaerobic production rates likely originate from microorganisms adapted to anaerobic conditions. All indicators of organic matter quality, FTIR ratios, SUVA254, E2:E3, HIX, FI and PARAFAC, provided similar results. Other than expected, wetting did not result in higher organic matter quality in bulk peat and leachate. Drier conditions in summer led to reduced organic matter quality. In pore water, long-term wetter conditions resulted in a higher organic matter quality. Slow-down of decomposition due to anaerobic conditions is unlikely, as this was not the case with respect to the other fractions. Mixing with groundwater could have transported organic matter of high quality to the wetted site. Potential CO2 production rates were not affected by long-term water table change. Organic matter quality of the wetted site may have been also overestimated in our study as vegetation change may have changed litter and peat quality as well. This study revealed that long-term wetting probably does not change organic matter quality as decisively as expected. Potential anaerobic CO2 and CH4 production rates rather increased as long as conditions were more constantly anoxic. Long-term lowered or fluctuating water table could potentially result in smaller future emissions due to a reduced organic matter quality, but also to less carbon sequestration.

Enriching of surface water in nutrients and DOC on the area of drained Kuwasy Mire in North-East Poland

NASA Astrophysics Data System (ADS)

Jaszczyński, Jacek; Sapek, Andrzej

2010-05-01

Key words: peatlands, drained areas, surface water, nutrients and DOC in water The object of this study was fundamental mineral component concentration (N-NO3, N-NH4, PO4, K, Na, Ca, Mg, Cl, Fe) and dissolved organic carbon concentration (DOC) in surface water in artificial canal running across drained fen area. Also pH, electrical conductivity and abssorbance A280 in water samples were measured. The investigations were localized on the area of drained and agricultural used Kuwasy Mire, which are situated in the middle basin of Biebrza River, in North-East Poland. Currently on the object there is superiority of peat-moorsh soils with moorsh layers to 25 cm of depth. The bog depth is determined from 60 to 140 cm. The most of area is occupied by soils with 110-120 cm organic layer which are intensive agricultural used. Mean annual ground water table amounted 55 cm. On the distance of 8 km (about 1100-1200 ha catchment area) fen space is crossed by Kuwaski Canal collecting water from draining network above describing peatland. Surface water samples were collected every month in three constant point of canal: at entrance on peatland (upper point) in the middle part (middle point) and in border part of peatland (lower point). The study was carried out in 2001-2009. The aim of this study was to determine enriching of surface water in individual mineral and organic components during flowing across peatland area. Mean concentration in whole research period for all investigated components was higher together with flowing of water in canal across fen area. The higest increments of mean concentration between upper a lower point of canal was connected with phosphorous and amonia. The concentrations of these compounds were adequately 4,8 i 2,6 times higher in lower part of canal. Mean concentrations of remaining compounds were 2-14% higher in water in lower point in comparision to upper point of canal. In course of interflow through peatland pH of water was decreasing but electrical conductivity and abssorbance A280 were increasing. When we take into consideration annual quantity of water flowing by canal only on biological level (0,5 m3/s) the increments load of PO4 in this distance amounted 3,6; N-NH4 - 4,6; N-NO3 - 3,0; DOC - 9,5 t.year-1. At mean interflow 3 m3/s the load of describing components was increasing to 21, 27, 20 i 57 t.year-1 in research part of canal.

Space Wire Upper Layer Protocols

NASA Technical Reports Server (NTRS)

Rakow, Glenn; Schnurr, Richard; Gilley, Daniel; Parkes, Steve

2004-01-01

This viewgraph presentation addresses efforts to provide a streamlined approach for developing SpaceWire Upper layer protocols which allows industry to drive standardized communication solutions for real projects. The presentation proposes a simple packet header that will allow flexibility in implementing a diverse range of protocols.

Predicting organic matter, nitrogen, and phosphorus concentrations in runoff from peat extraction sites using partial least squares regression

NASA Astrophysics Data System (ADS)

Tuukkanen, T.; Marttila, H.; Kløve, B.

2017-07-01

Organic matter and nutrient export from drained peatlands is affected by complex hydrological and biogeochemical interactions. Here partial least squares regression (PLSR) was used to relate various soil and catchment characteristics to variations in chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) concentrations in runoff. Peat core samples and water quality data were collected from 15 peat extraction sites in Finland. PLSR models constructed by cross-validation and variable selection routines predicted 92, 88, and 95% of the variation in mean COD, TN, and TP concentration in runoff, respectively. The results showed that variations in COD were mainly related to net production (temperature and water-extractable dissolved organic carbon (DOC)), hydrology (topographical relief), and solubility of dissolved organic matter (peat sulfur (S) and calcium (Ca) concentrations). Negative correlations for peat S and runoff COD indicated that acidity from oxidation of organic S stored in peat may be an important mechanism suppressing organic matter leaching. Moreover, runoff COD was associated with peat aluminum (Al), P, and sodium (Na) concentrations. Hydrological controls on TN and COD were similar (i.e., related to topography), whereas degree of humification, bulk density, and water-extractable COD and Al provided additional explanations for TN concentration. Variations in runoff TP concentration were attributed to erosion of particulate P, as indicated by a positive correlation with suspended sediment concentration (SSC), and factors associated with metal-humic complexation and P adsorption (peat Al, water-extractable P, and water-extractable iron (Fe)).

Net ecosystem CO2 exchange of a primary tropical peat swamp forest in Sarawak, Malaysia

NASA Astrophysics Data System (ADS)

Tang Che Ing, A.; Stoy, P. C.; Melling, L.

2014-12-01

Tropical peat swamp forests are widely recognized as one of the world's most efficient ecosystems for the sequestration and storage of carbon through both their aboveground biomass and underlying thick deposits of peat. As the peat characteristics exhibit high spatial and temporal variability as well as the structural and functional complexity of forests, tropical peat ecosystems can act naturally as both carbon sinks and sources over their life cycles. Nonetheless, few reports of studies on the ecosystem-scale CO2 exchange of tropical peat swamp forests are available to-date and their present roles in the global carbon cycle remain uncertain. To quantify CO2 exchange and unravel the prevailing factors and potential underlying mechanism regulating net CO2 fluxes, an eddy covariance tower was erected in a tropical peat swamp forest in Sarawak, Malaysia. We observed that the diurnal and seasonal patterns of net ecosystem CO2 exchange (NEE) and its components (gross primary productivity (GPP) and ecosystem respiration (RE)) varied between seasons and years. Rates of NEE declined in the wet season relative to the dry season. Conversely, both the gross primary productivity (GPP) and ecosystem respiration (RE) were found to be higher during the wet season than the dry season, in which GPP was strongly negatively correlated with NEE. The average annual NEE was 385 ± 74 g C m-2 yr-1, indicating the primary peat swamp forest functioned as net source of CO2 to the atmosphere over the observation period.

Emissions of volatile organic compounds and particulate matter from small-scale peat fire

EPA Science Inventory

Air pollution emitted from peat fires can negatively impact regional air quality, visibility, climate, and human health. Peat fires can smolder over long periods of time and, therefore, can release significantly greater amounts of carbon into the atmosphere per unit area compared...

Emissions of volatile organic compounds and particulate matter from small-scale peat fires

EPA Science Inventory

Air pollution emitted from peat fires can negatively impact regional air quality, visibility, climate, and human health. Peat fires can smolder over long periods of time and, therefore, can release significantly greater amounts of carbon into the atmosphere per unit area compared...

Ecohydrology of the wetland-forestland interface: hydrophobicity in leaf litter and its potential effect on surface evaporation

NASA Astrophysics Data System (ADS)

Probert, Samantha; Kettridge, Nicholas; Devito, Kevin; Hurley, Alexander

2017-04-01

Riparian wetlands represent an important ecotone at the interface of peatlands and forests within the Western Boreal Plain of Canada. Water storage and negative feedbacks to evaporation in these systems is crucial for the conservation and redistribution of water during dry periods and providing ecosystem resilience to disturbance. Litter cover can alter the relative importance of the physical processes that drive soil evaporation. Negative feedbacks to drying are created as the hydrophysical properties of the litter and soil override atmospheric controls on evaporation in dry conditions, subsequently dampening the effects of external forcings on the wetland moisture balance. In this study, water repellency in leaf litter has been shown to significantly correlate with surface-atmosphere interactions, whereby severely hydrophobic leaf litter is linked to the highest surface resistances to evaporation, and therefore lowest instantaneous evaporation. Decreasing moisture is associated with increasing hydrophobicity, which may reduce the evaporative flux further as the dry hydrophobic litter creates a hydrological disconnect between soil moisture and the atmosphere. In contrast, hydrophilic litter layers exhibited higher litter moistures, which is associated with reduced resistances to evaporation and enhanced evaporative fluxes. Water repellency of the litter layer has a greater control on evaporation than the presence or absence of litter itself. Litter removal had no significant effect on instantaneous evaporation or surface resistance to evaporation except under the highest evaporation conditions, where litter layers produced higher resistance values than bare peat soils. However, litter removal modified the dominant physical controls on evaporation: moisture loss in plots with leaf litter was driven by leaf and soil hydrophysical properties. Contrastingly, bare peat soils following litter removal exhibited cooler, wetter surfaces and were more strongly correlated to atmospheric controls. The interaction between evaporation, hydrophobicity and moisture of the soil surface, or litter, presents a potentially significant negative feedback to drying across wetland-forestland interfaces.

Peat Depth Assessment Using Airborne Geophysical Data for Carbon Stock Modelling

NASA Astrophysics Data System (ADS)

Keaney, Antoinette; McKinley, Jennifer; Ruffell, Alastair; Robinson, Martin; Graham, Conor; Hodgson, Jim; Desissa, Mohammednur

2013-04-01

The Kyoto Agreement demands that all signatory countries have an inventory of their carbon stock, plus possible future changes to this store. This is particularly important for Ireland, where some 16% of the surface is covered by peat bog. Estimates of soil carbon stores are a key component of the required annual returns made by the Irish and UK governments to the Intergovernmental Panel on Climate Change. Saturated peat attenuates gamma-radiation from underlying rocks. This effect can be used to estimate the thickness of peat, within certain limits. This project examines this relationship between peat depth and gamma-radiation using airborne geophysical data generated by the Tellus Survey and newly acquired data collected as part of the EU-funded Tellus Border project, together encompassing Northern Ireland and the border area of the Republic of Ireland. Selected peat bog sites are used to ground truth and evaluate the use of airborne geophysical (radiometric and electromagnetic) data and validate modelled estimates of soil carbon, peat volume and depth to bedrock. Data from two test line sites are presented: one in Bundoran, County Donegal and a second line in Sliabh Beagh, County Monaghan. The plane flew over these areas at different times of the year and at a series of different elevations allowing the data to be assessed temporally with different soil/peat saturation levels. On the ground these flight test lines cover varying surface land use zones allowing future extrapolation of data from the sites. This research applies spatial statistical techniques, including uncertainty estimation in geostatistical prediction and simulation, to investigate and model the use of airborne geophysical data to examine the relationship between reduced radioactivity and peat depth. Ground truthing at test line locations and selected peat bog sites involves use of ground penetrating radar, terrestrial LiDAR, peat depth probing, magnetometry, resistivity, handheld gamma-ray spectrometry, moisture content and rainfall monitoring combined with a real-time Differential Global Positioning System (DGPS) to monitor temporal and spatial variability of bog elevations. This research will assist in determining the accuracy and limitations of modelling soil carbon and changes in peat stocks by investigating the attenuation of gamma-radiation from underlying rocks. Tellus Border is supported by the EU INTERREG IVA programme, which is managed by the Special EU Programmes Body in Northern Ireland, the border Region of Ireland and western Scotland. The Tellus project was funded by the Northern Ireland Development of Enterprise Trade and Investment and by the Rural Development Programme through the Northern Ireland Programme for Building Sustainable Prosperity.

Holocene Tsunami Deposits From Large Tsunamis Along the Kuril Subduction Zone, Northeast Japan

NASA Astrophysics Data System (ADS)

Nanayama, F.; Furukawa, R.; Satake, K.; Soeda, Y.; Shigeno, K.

2003-12-01

Holocene tsunami deposits in eastern Hokkaido between Nemuro and Tokachi show that the Kuril subduction zone repeatedly produced earthquakes and tsunamis larger than those recorded in this region since AD 1804 (Nanayama et al., Nature, 424, 660-663, 2003). Twenty-two postulated tsunami sand layers from the past 9500 years are preserved on lake bottom near Kushiro City, and about ten postulated tsunami sand layers from the past 3000 years are preserved in peat layers on the coastal marsh of Kiritappu. We dated these ten tsunami deposits (named Ts1 to Ts10 from shallower to deeper) in peat layers by radiocarbon and tephrochronology, correlated them with historical earthquakes and tsunamis, and surveyed their spatial distribution to estimate the tsunamisO inland inundation limits. Ts10 and Ts9 are under regional tephra Ta-c2 (ca. 2.5 ka) and represent prehistorical events. Ts8 to Ts5 are between two regional tephra layers Ta-c2 and B-Tm (ca. 9th century). In particular, Ts5 is found just below B-Tm, so it is dated 9th century (Heian era). Ts4 is dated ca 13th century (Kamakura era), while Ts3, found just below Us-b and Ta-b (AD 1667-1663), is dated 17th century (Edo era). Ts2 is dated 19th century (Edo era) and may correspond to the AD 1843 Tempo Tokachi-oki earthquake (Mt 8.0) recorded in a historical document Nikkanki of Kokutai-ji temple at Akkeshi. Ts1 is inferred 20th century and may correspond to the tsunami from the AD 1960 Chilean earthquake (M 9.5) or the AD 1952 Tokachi-oki earthquake (Mt 8.2). Our detailed surveys indicate that Ts3 and Ts4 can be traced more than 3 km from the present coast line in Kirittapu marsh, much longer than the limits (< 1 km) of recent deposits Ts1 and Ts2 or documented inundation of the 19th and 20th century tsunamis. The recurrence intervals of great tsunami inundation are about 400 to 500 years, longer than that of typical interplate earthquakes along the Kuril subduction zone. The longer interval and the apparent large tsunami inundation indicate unusual origin of these tsunamis.

Scales and Patterns of Nitrate Transport and Transformation in the Hyporheic Zone of a Lowland River

NASA Astrophysics Data System (ADS)

Naden, E.; Krause, S.; Tecklenburg, C.; Munz, M.

2009-04-01

The Hyporheic Zone (HZ) represents the spatially and temporally variable part of the streambed that is affected by the mixture of groundwater and surface water and often characterised by strong redox gradients and high turnover rates of redox reactive substances. The HZ has often been understood as a complex bioreactor with a high potential to affect groundwater-surface water exchange as well control the chemical signature of waters along the hyporheic passage. Currently, 73% of groundwater and 28% of UK rivers sampled exhibit either high nitrate levels or rising trends (Defra, 2008) Because of the high metabolic rates that have often be observed, the HZ is by many expected to potentially ameliorate groundwater nitrate fluxes and thus to reduce nitrate pollution and benefit freshwater ecosystems. The objective of this pilot study was to set up a monitoring program on a typical lowland river within glacio-fluvial deposits and well connected to the shallow groundwater aquifer. This study aims to derive a conceptual model of hyporheic exchange and nutrient metabolism in an agriculturally used lowland system including the development of upscaling strategies that allow for the assessment of hyporheic uptake or contribution on a subcatchment scale. The research area covers a 250 metre stream reach of the River Tern (Shropshire, UK), a lowland groundwater dependent surface water body at risk of failing to achieve ‘good water' status under the WFD, primarily due to diffuse agricultural pollution. In two horizontal arrays 42 multi piezometers have been installed in the river bed offering sampling from between three and eight sampling points ranging from 5 cm to 200 cm depth. These allow the sampling of streambed porewater from more than 150 locations. Additionally, ten shallow groundwater boreholes (up to 3m depth) have been installed within the riparian floodplain. From June to September 2008 head measurements were taken at the streambed piezometers, riparian groundwater boreholes and the river in order to determine the groundwater flowfield and exchange with the surface water. At the same time interval streambed pore water and riparian groundwater were sampled from piezometers and boreholes alongside surface water samples from the river. The samples were analysed for dissolved oxygen and major anion concentrations. Initial results confirm indicate that the water sources mixing in the HZ are statistically distinctive. In contrast to the many observed head water streams the exchange between groundwater and surface water is not just determined by gradually changing hydraulic conductivities of the sediment material but strongly controlled by the spatial pattern of a discontinuous impermeable regional peat layer located in 50 cm depth on average. The peat layer is separating the fluxes within the streambed into two (partially connected) flow systems, with semi-confined conditions underneath and pattern of surface water mixing above the peat. Areas where the peat layer is disrupted are characterised by strong connection of both flow systems. Dependent on flow paths and residence times redox conditions and nitrate concentrations are showing substantial changes along the hyporheic flow path. The spatial very heterogeneous patterns of nitrate concentrations in the streambed were found controlled by complex flow processes at multiple scales covering small scale hyporheic exchange in pools, riffles and sand bars as well as large scale pattern of groundwater - surface water connectivity and riparian influences.

Comparison of pelletized biochar derived from two source materials as replacements for peat in potting substrates

USDA-ARS?s Scientific Manuscript database

Soilless substrates are primarily used in the production of containerized greenhouse and nursery crops, with sphagnum peat moss being a primary constituent of most substrates. We are examining biochars for several horticultural applications, including as peat moss replacements. Biochar was prepared ...

Characterisation of VOC, SVOC, and PM emissions from peat burnt in laboratory simulations

EPA Science Inventory

Peat, or organic soil, is a vast store of organic carbon, widely distributed from polar temperate to equatorial regions. Drainage for agriculture and drought are drying vast areas of peat, exposing it to increasing fire risk, which may be exacerbated by climate change. This has ...

Development of a Palliative Education Assessment Tool for Medical Student Education.

ERIC Educational Resources Information Center

Meekin, Sharon Abele; Klein, Jason E.; Fleischman, Alan R.; Fins, Joseph J.

2000-01-01

Describes the Palliative Education Assessment Tool (PEAT), an innovative assessment to facilitate curricular mapping of palliative care education. The PEAT comprises seven palliative care domains, each of which details specific objectives of knowledge, skills, and attitudes. PEAT enables educators to describe a specific multidimensional aspect of…

Posidonia oceanica (L.) based compost as substrate for potted basil production.

PubMed

Mininni, Carlo; Grassi, Francesco; Traversa, Andreina; Cocozza, Claudio; Parente, Angelo; Miano, Teodoro; Santamaria, Pietro

2015-08-15

Peat is the main component of growing media but is also a non-renewable resource; therefore European policy strongly encourages the use of peat alternatives such as compost. Posidonia is a Mediterranean seagrass that produces very conspicuous onshore deposits that can be composted. In this study, a commercial green compost and a Posidonia residue-based compost were tested in order to assess their potential use as substitutes or complements to peat. All macro and micro-element concentrations of the substrates were positively and significantly related to the percentage of composts in the growing media. Plant grown on peat showed higher content of P, Ca, K, Na, Cu, Mn, Zn and Fe, and a slightly higher biomass production in comparison to compost-based growing media. In contrast, plants grown on compost-based substrates showed lower uptake of Cd and Cr than peat. The results indicate that both composts can be used as a complement to the peat for substrate preparation, especially at a rate of 30%. The Posidonia-based compost showed better productive results in comparison to the green one. Basil grown on the two compost-based media showed reduced absorption level of potentially toxic metals in comparison to peat. © 2014 Society of Chemical Industry.

Stable carbon and nitrogen isotopes in vertical peat profiles of natural and drained boreal peatlands

NASA Astrophysics Data System (ADS)

Nykänen, Hannu; Mpamah, Promise; Rissanen, Antti; Pitkänen, Aki; Turunen, Jukka; Simola, Heikki

2015-04-01

Peatlands form a significant carbon pool in the global carbon cycle. Change in peat hydrology, due to global warming is projected to change microbiological processes and peat carbon pool. We tested if bulk stable carbon and nitrogen isotopes serve as indicators of severe long term drying in peatlands drained for forestry. Depth profile analysis of peat, for their carbon and nitrogen content as well as their carbon and nitrogen stable isotopic signatures, were conducted for peatlands in southern and eastern Finland, having ombrotrophic and minerotrophic natural and corresponding drained pairs or separate drained sites. The selection of sites allowed us to compare changes due to different fertility and changes due to long term artificial drying. Drainage lasting over 40 years has led to changes in hydrology, vegetation, nutrient mineralization and respiration. Furthermore, increased nutrient uptake and possible recycling of peat nitrogen and carbon trough vegetation back to the peat surface, also possibly has an effect on the stable isotopic composition of peat carbon and nitrogen. We think that drainage induced changes somehow correspond to those caused by changed hydrology due to climate change. We will present data from these measurements and discuss their implications for carbon and nitrogen flows in peatlands.

Saprophytic and Potentially Pathogenic Fusarium Species from Peat Soil in Perak and Pahang

PubMed Central

Karim, Nurul Farah Abdul; Mohd, Masratulhawa; Nor, Nik Mohd Izham Mohd; Zakaria, Latiffah

2016-01-01

Isolates of Fusarium were discovered in peat soil samples collected from peat swamp forest, waterlogged peat soil, and peat soil from oil palm plantations. Morphological characteristics were used to tentatively identify the isolates, and species confirmation was based on the sequence of translation elongation factor-1α (TEF-1α) and phylogenetic analysis. Based on the closest match of Basic Local Alignment Search Tool (BLAST) searches against the GenBank and Fusarium-ID databases, five Fusarium species were identified, namely F. oxysporum (60%), F. solani (23%), F. proliferatum (14%), F. semitectum (1%), and F. verticillioides (1%). From a neighbour-joining tree of combined TEF-1α and β-tubulin sequences, isolates from the same species were clustered in the same clade, though intraspecies variations were observed from the phylogenetic analysis. The Fusarium species isolated in the present study are soil inhabitants and are widely distributed worldwide. These species can act as saprophytes and decomposers as well as plant pathogens. The presence of Fusarium species in peat soils suggested that peat soils could be a reservoir of plant pathogens, as well-known plant pathogenic species such F. oxysporum, F. solani, F. proliferatum, and F. verticillioides were identified. The results of the present study provide knowledge on the survival and distribution of Fusarium species. PMID:27019679

Sequestration of arsenic in ombrotrophic peatlands

NASA Astrophysics Data System (ADS)

Rothwell, James; Hudson-Edwards, Karen; Taylor, Kevin; Polya, David; Evans, Martin; Allott, Tim

2014-05-01

Peatlands can be important stores of arsenic but we are lacking spectroscopic evidence of the sequestration pathways of this toxic metalloid in peatland environments. This study reports on the solid-phase speciation of anthropogenically-derived arsenic in atmospherically contaminated peat from the Peak District National Park (UK). Surface and sub-surface peat samples were analysed by synchrotron X-ray absorption spectroscopy on B18 beamline at Diamond Light Source (UK). The results suggest that there are contrasting arsenic sequestration mechanisms in the peat. The bulk arsenic speciation results, in combination with strong arsenic-iron correlations at the surface, suggest that iron (hydr)oxides are key phases for the immobilisation of arsenic at the peat surface. In contrast, the deeper peat samples are dominated by arsenic sulphides (arsenopyrite, realgar and orpiment). Given that these peats receive inputs solely from the atmosphere, the presence of these sulphide phases suggests an in-situ authigenic formation. Redox oscillations in the peat due to a fluctuating water table and an abundant store of legacy sulphur from historic acid rain inputs may favour the precipitation of arsenic sequestering sulphides in sub-surface horizons. Oxidation-induced loss of these arsenic sequestering sulphur species by water table drawdown has important implications for the mobility of arsenic and the quality of waters draining peatlands.

Resilient modulus characteristics of soil subgrade with geopolymer additive in peat

NASA Astrophysics Data System (ADS)

Zain, Nasuhi; Hadiwardoyo, Sigit Pranowo; Rahayu, Wiwik

2017-06-01

Resilient modulus characteristics of peat soil are generally very low with high potential of deformation and low bearing capacity. The efforts to improve the peat subgrade resilient modulus characteristics is required, one among them is by adding the geopolymer additive. Geopolymer was made as an alternative to replace portland cement binder in the concrete mix in order to promote environmentally friendly, low shrinkage value, low creep value, and fire resistant material. The use of geopolymer to improve the mechanical properties of peat as a road construction subgrade, hence it becomes important to identify the effect of geopolymer addition on the resilient modulus characteristics of peat soil. This study investigated the addition of 0% - 20% geopolymer content on peat soil derived from Ogan Komering Ilir, South Sumatera Province. Resilient modulus measurement was performed by using cyclic triaxial test to determine the resilience modulus model as a function of deviator stresses and radial stresses. The test results showed that an increase in radial stresses did not necessarily lead to an increase in modulus resilient, and on the contrary, an increase in deviator stresses led to a decrease in modulus resilient. The addition of geopolymer in peat soil provided an insignificant effect on the increase of resilient modulus value.

How does whole ecosystem warming of a peatland affect methane production and consumption?

NASA Astrophysics Data System (ADS)

Hopple, A.; Brunik, K.; Keller, J.; Pfeifer-Meister, L.; Woerndle, G.; Zalman, C.; Hanson, P.; Bridgham, S. D.

2017-12-01

Peatlands are among Earth's most important terrestrial ecosystems due to their massive soil carbon (C) stores and significant release of methane (CH4) into the atmosphere. Methane has a sustained-flux global warming potential 45-times greater than carbon dioxide (CO2), and the accuracy of Earth system model projections relies on our mechanistic understanding of peatland CH4 cycling in the context of environmental change. The objective of this study was to determine, under in situ conditions, how heating of the peat profile affects ecosystem-level anaerobic C cycling. We assessed the response of CO2 and CH4 production, as well as the anaerobic oxidation of CH4 (AOM), in a boreal peatland following 13 months of deep peat heating (DPH) and 16 months of subsequent whole-ecosystem warming (surface and deep heating; WEW) as part of the Spruce and Peatland Responses Under Changing Environments (SPRUCE) project in northern Minnesota, USA. The study uses a regression-based experimental design including 5 temperature treatments that warmed the entire 2 m peat profile from 0 to +9 °C above ambient temperature. Soil cores were collected at multiple depths (25-200 cm) from each experimental chamber at the SPRUCE site and anaerobically incubated at in situ temperatures for 1-2 weeks. Methane and CO2 production in surface peat were positively correlated with elevated temperature, but no consistent temperature response was found at depth (75-200 cm) following DPH. However, during WEW, we observed significant increases in both surface and deep peat methanogenesis with increasing temperature. Surface peat had greater CH4 production rates than deeper peat, implying that the increased CH4 emissions observed in the field were largely driven by surface peat warming. The CO2:CH4 ratio was inversely correlated with temperature across all depths following 16 months of WEW, indicating that the entire peat profile is becoming more methanogenic with warming. We also observed AOM throughout the whole peat profile, with the highest rates observed at the surface and initial data suggesting a positive correlation with increasing temperature. While SPRUCE will continue for many years, our initial results suggest that the vast C stores at depth in peatlands are minimally responsive to warming and any response will be driven largely by surface peat.

Effect of Different Peat Size and Pre-Consolidation Pressure of Reconstituted Peat on Effective Undrained Shear Strength Properties

NASA Astrophysics Data System (ADS)

Azhar, ATS; Norhaliza, W.; Ismail, B.; Ezree, AM; Nizam, ZM

2017-08-01

Shear strength of the soil is one of the most important parameters in engineering design, especially during the pre- or post-construction periods, since it is mainly used to measure and evaluate the foundation or slope stability of soil. Peat normally known as a soil that has a very low value of shear strength, and in order to determine and understand the shear strength of the peat, it is a difficult task in geotechnical engineering due to several factors such as types of fabrics, the origin of the soil, water content, organic matter and the degree of humification. The aim of this study is to determine the effective undrained shear strength properties of reconstituted peat of different sizes. All the reconstituted peat samples were formed with the size that passed the opening sieve of 0.425 mm (

Petrography and geochemistry of the San Miguel lignite, Jackson Group (Eocene), south Texas

USGS Publications Warehouse

Warwick, Peter D.; Crowley, Sharon S.; Ruppert, Leslie F.; Pontolillo, James

1996-01-01

The San Miguel lignite deposit (late Eocene, lower Jackson Group) of south Texas consists of four or more thin (generally < 1 m thick) lignite benches that are separated by claystone and mudstone partings. The partings are composed of altered volcanic air-fall ash that has been reworked by tidal or channel processes associated with a back-barrier depositional environment. The purpose of this study is to examine the relationship between the ash yield and the petrographic and geochemical characteristics of the San Miguel lignite as mined. Particular attention is given to 12 of the environmentally sensitive trace elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) that have been identified as possible hazardous air pollutants (HAPs) by the United States Clean Air Act Amendments of 1990. A total of 29 rock and lignite samples were collected and characterized by geochemical and petrographic methods. The major conclusions of the study are as follows: (1) The distribution of Mn is inversely related to the ash yield of the lignite samples. This indicates an organic affinity, or an association with finely disseminated minerals in the lignite that contain this element. (2) On a whole-coal basis, the concentration of the HAPs' element Pb is positively related to ash yield in lignite samples. This indicates an inorganic affinity for Pb. (3) Average whole-coal concentrations of As, Be, Sb, and U in the San Miguel samples are greater than published averages for these elements in other U.S. lignites. (4) The upper and lower lignite benches of the San Miguel deposit are both ash- and algal-rich, indicating that these intervals were probably deposited in wetter conditions than those in which the middle intervals formed. (5) The dominance of the eugelinite maceral subgroup over the huminite subgroup indicates that the San Miguel lignites were subjected to peat-forming conditions (either biogenic or chemical) that enabled degradation of wood cellular material into matrix gels, or that the plants that formed these lignite benches were less woody and more prone to formation of matrix gels. (6) An inertinite-rich layer (top of the B bed) might have formed from widespread oxidation of the San Miguel peat as a result of a volcanic ash fall which was subsequently reworked.

Anomalies of the upper water column in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Rivetti, Irene; Boero, Ferdinando; Fraschetti, Simonetta; Zambianchi, Enrico; Lionello, Piero

2017-04-01

The evolution of the upper water column in the Mediterranean Sea during more than 60 years is reconstructed in terms of few parameters describing the mixed layer and the seasonal thermocline. The analysis covers the period 1945-2011 using data from three public sources: MEDAR-MEDATLAS, World Ocean Database, MFS-VOS program. Five procedures for estimating the mixed layer depth are described, discussed and compared using the 20-year long time series of temperature profiles of the DYFAMED station in the Ligurian Sea. On this basis the so-called three segments profile model (which approximates the upper water column with three segments representing mixed layer, thermocline and deep layer) has been selected for a systematic analysis at Mediterranean scale. A widespread increase of the thickness and temperature of the mixed layer, increase of the depth and decrease of the temperature of the thermocline base have been observed in summer and autumn during the recent decades. It is shown that positive temperature extremes of the mixed layer and of its thickness are potential drivers of the mass mortalities of benthic invertebrates documented since 1983. Hotspots of mixed layer anomalies have been also identified. These results refine previous analyses showing that ongoing and future warming of upper Mediterranean is likely to increase mass mortalities by producing environmental conditions beyond the limit of tolerance of some benthic species.

Evolution of Meso-Cenozoic lithospheric thermal-rheological structure in the Jiyang sub-basin, Bohai Bay Basin, eastern North China Craton

NASA Astrophysics Data System (ADS)

Xu, Wei; Qiu, Nansheng; Wang, Ye; Chang, Jian

2018-01-01

The Meso-Cenozoic lithospheric thermal-rheological structure and lithospheric strength evolution of the Jiyang sub-basin were modeled using thermal history, crustal structure, and rheological parameter data. Results indicate that the thermal-rheological structure of the Jiyang sub-basin has exhibited obvious rheological stratification and changes over time. During the Early Mesozoic, the uppermost portion of the upper crust, middle crust, and the top part of the upper mantle had a thick brittle layer. During the early Early Cretaceous, the top of the middle crust's brittle layer thinned because of lithosphere thinning and temperature increase, and the uppermost portion of the upper mantle was almost occupied by a ductile layer. During the late Early Cretaceous, the brittle layer of the middle crust and the upper mantle changed to a ductile one. Then, the uppermost portion of the middle crust changed to a thin brittle layer in the late Cretaceous. During the early Paleogene, the thin brittle layer of the middle crust became even thinner and shallower under the condition of crustal extension. Currently, with the decrease in lithospheric temperature, the top of the upper crust, middle crust, and the uppermost portion of the upper mantle are of a brittle layer. The total lithospheric strength and the effective elastic thickness ( T e) in Meso-Cenozoic indicate that the Jiyang sub-basin experienced two weakened stages: during the late Early Cretaceous and the early Paleogene. The total lithospheric strength (approximately 4-5 × 1013 N m-1) and T e (approximately 50-60 km) during the Early Mesozoic was larger than that after the Late Jurassic (2-7 × 1012 N m-1 and 19-39 km, respectively). The results also reflect the subduction, and rollback of Pacific plate is the geodynamic mechanism of the destruction of the eastern North China Craton.

The geology of selected peat-forming environments in temperate and tropical latitudes

USGS Publications Warehouse

Cameron, C.C.; Palmer, C.A.; Esterle, J.S.

1990-01-01

We studied peat in several geologic and climatic settings: (1) a glaciated terrain in cold-temperate Maine and Minnesota, U.S.A.; (2) an island in a temperate maritime climate in the Atlantic Ocean off the coast of Maine, U.S.A., where sea level is rising rapidly and changing the environment of peat accumulation; (3) swamps along the warm-temperate U.S. Atlantic and Gulf Coastal Plains, where sea level has changed often, thus creating sites for accumulation; and (4) in a tropical climate along the coast of Sarawak, Malaysia, and the delta of the Batang Hari River, Sumatra, Indonesia (Figs. 1 and 2). With the exception of the deposits on the Atlantic and Gulf Coastal Plains, most of the deposits described are domed bogs in which peat accumulation continued above the surface of the surrounding soil. The bogs of the U.S. Atlantic and Gulf Coastal Plains have almost level surfaces. All domed bogs are not entirely ombrotrophic (watered only from precipitation); multidomed bogs that rise from irregular or hilly surfaces may be crossed by streams that supply water to the bogs. The geologic processes or organic sedimentation, namely terrestrialization and paludification, are similar in all peat deposits considered here. Differences in geomorphology affecting the quantity and that quality of peat that has ash contents of less than 25%, which are desirable for commercial purposes, depend chiefly on: (1) high humidity, which is favorable to luxuriant growth of peat-forming vegetation; (2) a depositional setting that permits extensive accumulation relatively free from inorganic contamination from sea water and streams and from dust and volcanic ash; and (3) a stable regional water table that controls the rate of decomposition under aerobic conditions and protects the deposit against the ravages of fire. Differences in peat textures are due to the type of vegetation and to the degree of decomposition. The rate of decomposition is largely the result of the amount of oxidation and aerobic microbial activity. Stratigraphic distribution of various textures and amounts of inorganic components within a peat deposit is largely determined by the vertical positions occupied by peat-forming environments, such as pond, marsh, swamp and heath where vegetation accumulated, and the depth to zones of unoxygenated water. Peat also differs in the rate of accumulation. On the basis of carbon-14 dating, an estimated 8 m of peat in the tropical Batang Hari River deposit in Sumatra has been accumulating at the rate of about 1.5 m/1,000 yr, whereas peat in the cold-temperate deposit in Maine has been accumulating at the rate of 0.66 m/1,000 yr. Accumulation rates in domed deposits such as these are affected not only by factors controlling volume of biomass and aerobic decay but also by stream erosion and fires that remove peat. Such disconformities (see Fig. 2) within the deposit may be recognized by sudden vertical changes in degree of decomposition and/or the presence of charcoal. The trace-element content of peat deposits is affected by the environments of their settings. Samples of peat that have an ash content of less than 25% dry weight and that are from small, almost level swamp deposits along the Atlantic Coastal Plain of North Carolina were compared with similar samples from small domed bogs in Maine, a glaciated area. Samples from Nort Carolina, which are from deposits in thick fluvial and nearshore marine sediments far from the bedrock source, are generally higher in Ti, Cr and Pb. The Maine samples from deposits in glacial drift close to the bedrock source contain more Zn, Mn, P, Ca, Na and Fe. The kind and amount of trace elements within the deposits appear to relate largely to depositional setting, to kinds of bedrock source, and to the modes of transportation from source to peat swamp. Trace-element concentrations in the extensive Sumatra peat deposit, which represents a potentially commercial coal bed, are similar to those found in Appalachian c

Evaluation of a peat moss plus soybean oil (PMSO) technology for reducing explosive residue transport to groundwater at military training ranges under field conditions.

PubMed

Fuller, Mark E; Schaefer, Charles E; Steffan, Robert J

2009-11-01

An evaluation of peat moss plus crude soybean oil (PMSO) for mitigation of explosive contamination of soil at military facilities was performed using large soil lysimeters under field conditions. Actual range soils were used, and two PMSO preparations with different ratios of peat moss:soybean oil (1:1, PO1; 1:2, PO2) were compared to a control lysimeter that received no PMSO. PMSO was applied as a 10 cm layer on top of the soil, and Composition B detonation residues from a 55-mm mortar round were applied at the surface of each of the lysimeters. Dissolution of the residues occurred during natural precipitation events over the course of 18 months. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) emanating from the Composition B residues were significantly reduced by the PO2 PMSO material compared to the untreated control. Soil pore water RDX concentrations and RDX fluxes were reduced over 100-fold compared to the control plots at comparable depths. Residual RDX in the soil profile was also significantly lower in the PMSO treated plots. PO1 PMSO resulted in lower reductions in RDX transport than the PO2 PMSO. The transport of the RDX breakdown product hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) was also greatly reduced by the PMSO materials. Results were in general agreement with a previously developed fate and transport model describing PMSO effectiveness. These results demonstrate the potential effectiveness of the inexpensive and environmentally benign PMSO technology for reducing the subsurface loading of explosives at training ranges and other military facilities.

Ecosystem and physiological controls over methane production in northern wetlands

NASA Technical Reports Server (NTRS)

Valentine, David W.; Holland, Elisabeth A.; Schimel, David S.

1994-01-01

Peat chemistry appears to exert primary control over methane production rates in the Canadian Northern Wetlands Study (NOWES) area. We determined laboratory methane production rate potentials in anaerobic slurries of samples collected from a transect of sites through the NOWES study area. We related methane production rates to indicators of resistance to microbial decay (peat C: N and lignin: N ratios) and experimentally manipulated substrate availability for methanogenesis using ethanol (EtOH) and plant litter. We also determined responses of methane production to pH and temperature. Methane production potentials declined along the gradient of sites from high rates in the coastal fens to low rates in the interior bogs and were generally highest in surface layers. Strong relationships between CH4 production potentials and peat chemistry suggested that methanogenesis was limited by fermentation rates. Methane production at ambient pH responded strongly to substrate additions in the circumneutral fens with narrow lignin: N and C: N ratios (delta CH4/delta EtOH = 0.9-2.3 mg/g) and weakly in the acidic bogs with wide C: N and lignin: N ratios (delta CH4/delta EtOH = -0.04-0.02 mg/g). Observed Q(sub 10) values ranged from 1.7 to 4.7 and generally increased with increasing substrate availability, suggesting that fermentation rates were limiting. Titration experiments generally demonstrated inhibition of methanogenesis by low pH. Our results suggest that the low rates of methane emission observed in interior bogs during NOWES likely resulted from pH and substrate quality limitation of the fermentation step in methane production and thus reflect intrinsically low methane production potentials. Low methane emission rates observed during NOWES will likely be observed in other northern wetland regions with similar vegetation chemistry.

Evaluating the Sonic Layer Depth Relative to the Mixed Layer Depth

DTIC Science & Technology

2008-07-24

upper ocean to trap acoustic energy in a surface duct while MLD characterizes upper ocean mixing. The SLD is computed from temperature and salinity...and compared over the annual cycle. The SLD characterizes the potential of the upper ocean to trap acoustic energy in a surface duct while MLD...exists a tropical cyclone formation [e.g., Mao et al., 2000], to Minimum acoustic Cutoff Frequency (MCF) above which phytoplankton bloom critical depth

Influences and interactions of inundation, peat, and snow on active layer thickness: Modeling Archive

DOE Data Explorer

Scott Painter; Ethan Coon; Cathy Wilson; Dylan Harp; Adam Atchley

2016-04-21

This Modeling Archive is in support of an NGEE Arctic publication currently in review [4/2016]. The Advanced Terrestrial Simulator (ATS) was used to simulate thermal hydrological conditions across varied environmental conditions for an ensemble of 1D models of Arctic permafrost. The thickness of organic soil is varied from 2 to 40cm, snow depth is varied from approximately 0 to 1.2 meters, water table depth was varied from -51cm below the soil surface to 31 cm above the soil surface. A total of 15,960 ensemble members are included. Data produced includes the third and fourth simulation year: active layer thickness, time of deepest thaw depth, temperature of the unfrozen soil, and unfrozen liquid saturation, for each ensemble member. Input files used to run the ensemble are also included.

Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

NASA Astrophysics Data System (ADS)

Sasaki, H.; Matsuno, K.; Fujiwara, A.; Onuka, M.; Yamaguchi, A.; Ueno, H.; Watanuki, Y.; Kikuchi, T.

2015-11-01

The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

Numerical Investigations of Wave-Induced Mixing in Upper Ocean Layer

NASA Astrophysics Data System (ADS)

Guan, Changlong

2017-04-01

The upper ocean layer is playing an important role in ocean-atmosphere interaction. The typical characteristics depicting the upper ocean layer are the sea surface temperature (SST) and the mixed layer depth (MLD). So far, the existing ocean models tend to over-estimate SST and to under-estimate MLD, due to the inadequate mixing in the mixing layer, which is owing to that several processes related mixing in physics are ignored in these ocean models. The mixing induced by surface gravity wave is expected to be able to enhance the mixing in the upper ocean layer, and therefore the over-estimation of SST and the under-estimate of MLD could be improved by including wave-induced mixing. The wave-induced mixing could be accomplished by the physical mechanisms, such as wave breaking (WB), wave-induced Reynolds stress (WR), and wave-turbulence interaction (WT). The General Ocean Turbulence Model (GOTM) is employed to investigate the effects of the three mechanisms concerning wave-induced mixing. The numerical investigation is carried out for three turbulence closure schemes, say, k-epsilon, k-omega and Mellor-Yamada (1982), with the observational data from OSC Papa station and wave data from ECMWF. The mixing enhancement by various waved-induced mixing mechanisms is investigated and verified.

Seasonal patterns of cytokinins and microclimate and the mediation of gas exchange among canopy layers of mature Acer saccharum trees.

PubMed

Reeves, Ian; Emery, R J Neil

2007-11-01

Seasonal patterns of cytokinins (CKs) and microclimate were examined in the upper, middle and lower canopy layers of mature Acer saccharum Marsh. (sugar maple) trees to elucidate the potential role of CKs in the mediation of gas exchange. The upper canopy showed a distinctly dissimilar microclimate from the middle and lower canopy layers with higher photosynthetically active radiation and wind speed, but showed no corresponding differences in transpiration (E) or stomatal conductance (g(s)). Although E and g(s) tended to be higher in the upper canopy than in the middle and lower canopies, the differences were not significant, indicating regulation beyond the passive response to changes in microclimate. The upper canopy accumulated significantly higher concentrations of CKs, predominantly as ribosides, and all canopy layers showed distinct seasonal patterns in CK profiles. Multiple regression models showed significant relationships between both g(s) and E and foliar CK concentration, although these relationships varied among canopy layers. The relationships were strongest in the middle and lower canopy layers where there was less fluctuation in leaf water status and less variability in abiotic variables. The relationships between gas exchange parameters and leaf CK concentration began to decouple near the end of the growing season as foliar phytohormone concentrations changed with the approach of dormancy.

Extensometer, water-level, and lithologic data from Bacon and Bethel Islands in Sacramento-San Joaquin Delta, California, September 1987 to August 1993

USGS Publications Warehouse

Kerr, Barry D.; Leighton, David A.

1999-01-01

Compaction, water-level, and lithologic data were collected at extensometer sites on Bacon and Bethel Islands, anchored at 436 and 536 feet below land surface, respectively. The data reported here are part of a study of the processes causing subsidence in the Sacramento?San Joaquin Delta. The depths were selected to ensure that they were well below the peat layer and the primary aquifer, which minimized the effects of peat loss and shallow ground-water withdrawal. Compaction and depth to ground water were measured monthly at Bacon Island from September 1987 through August 1993 and at Bethel Island from August 1988 through August 1993. After automatic digital data loggers were installed at Bacon Island in December 1988 and at Bethel Island in September 1989, hourly readings also were made. Calculated rates of compaction were 0.0015 and 0.0016 feet per year at Bacon and Bethel Islands, respectively. Cumulative compaction at the Bacon Island site from September 1987 to August 1993 was about 0.009 feet. Cumulative compaction at the Bethel Island site from August 1988 to August 1993 was about 0.008 feet.

Effects of environmental and anthropogenic determinants on changes in groundwater levels in selected peat bogs of Slowinski National Park, northern Poland

NASA Astrophysics Data System (ADS)

Chlost, Izabela; Cieśliński, Roman

2018-03-01

The present study focuses on two Baltic-type peat bogs in Slowinski National Park, namely that at Żarnowskie and at Kluki, located in the Lake Łebsko catchment and both characterised by a centrally located dome with a very marshy fringe area featuring an emerging marshy coniferous forest (Vaccinio uliginosi-Pinetum). The Żarnowskie bog is under active protection. A total of 24 flow barriers were installed in drainage ditches during the years 2006 and 2007. The purpose of these barriers was to put a halt to water outflow. In addition, 30 hectares of young pine forest were cleared in order to decrease loss of water via evapotranspiration. Kluki peat bog is only partially protected by Polish law. The lack of efforts to prevent outflow via the canal is due to the fact that the canal is utilised to drain meadows in the vicinity of the village of Łokciowe outside of the national park. Peat formation no longer occurs in this peat bog. The hydrological condition of the bog is catastrophic as a result of its main canal, referred to as Canal C9, which is 2.5 to 3.0 m deep and 10 m wide in places. Both peat bogs are monitored for fluctuations in groundwater. Research has shown that changes in water levels fluctuate based on season of the year and geographical location, which is illustrated quite well using the two studied peat bogs. The water retention rate of the Żarnowskie peat bog may be considered fairly high and is likely to improve due to protective measures enabled by Polish environmental laws. The water retention rate of the bog is consistently improving thanks to these measures, fluctuations in water level are small and the water level does not drop under 0.5 m below ground level even under extreme hydrometeorological conditions. This yields optimum conditions for renewed peat formation in this area. One potential threat is the Krakulice peat extraction facility, which is located in the southern part of the bog close to the boundary with the national park.

Effect of mixing geopolymer and peat on bearing capacity in Ogan Komering Ilir (OKI) by California bearing ratio (CBR) test

NASA Astrophysics Data System (ADS)

Raharja, Danang S.; Hadiwardoyo, Sigit P.; Rahayu, Wiwik; Zain, Nasuhi

2017-06-01

Geopolymer is binder material that consists of solid material and the activator solution. Geopolymer material has successfully replaced cement in the manufacture of concrete with aluminosilicate bonding system. Geopolymer concrete has properties similar to cement concrete with high compressive strength, low shrinkage value, relatively low creep value, as well as acid-resistant. Based on these, the addition of polymers in peat soils is expected to improve the bearing capacity of peat soils. A study on the influence of geopolymer addition in peat soils was done by comparing before and after the peat soil was mixed with geopolymer using CBR (California Bearing Ratio) test in unsoaked and soaked conditions. 10% mixture content of the peat dry was used, weighted with a variety of curing time 4 hours, 5 days, and 10 days. There were two methods of mixing: first, peat was mixed with fly ash geopolymer activators and mixed solution (waterglass, NaOH, water), and second, peat was mixed with fly ash and mixed geopolymer (waterglass, NaOH, water, fly ash). Changes were observed in specific gravity, dry density, acidity (pH), and the microscopic structure with Scanning Electron Microscope (SEM). Curing time did not significantly affect the CBR value. It even shows a tendency to decline with longer curing time. The first type mixture obtained CBR value of: 5.4% for 4 hours curing, 4.6% for 5 days curing and 3.6% for 10 days curing. The second type mixture obtained CBR value of: 6.1% for 4 hours curing, 5.2% for 5 days curing and 5.2% for 10 days curing. Furthermore, the specific gravity value, dry density, pH near neutral and swelling percentage increased. From both variants, the second type mixture shows better results than the first type mixture. The results of SEM (Scanning Electron Microscopy) show the structure of the peat which became denser with the fly ash particles filling the peat microporous. Also, the reaction of fly ash with geopolymer is indicated by the solid agglomerates that are larger than normal fly ash particle size.

Temperature-driven adaptation of the bacterial community in peat measured by using thymidine and leucine incorporation.

PubMed

Ranneklev, S B; Bååth, E

2001-03-01

The temperature-driven adaptation of the bacterial community in peat was studied, by altering temperature to simulate self-heating and a subsequent return to mesophilic conditions. The technique used consisted of extracting the bacterial community from peat using homogenization-centrifugation and measuring the rates of thymidine (TdR) or leucine (Leu) incorporation by the extracted bacterial community at different temperatures. Increasing the peat incubation temperature from 25 degrees C to 35, 45, or 55 degrees C resulted in a selection of bacterial communities whose optimum temperatures for activity correlated to the peat incubation temperatures. Although TdR and Leu incorporations were significantly correlated, the Leu/TdR incorporation ratios were affected by temperature. Higher Leu/TdR incorporation ratios were found at higher temperatures of incubation of the extracted bacterial community. Higher Leu/TdR incorporation ratios were also found for bacteria in peat samples incubated at higher temperatures. The reappearance of the mesophilic community and disappearance of the thermophilic community when the incubation temperature of the peat was shifted down were monitored by measuring TdR incorporation at 55 degrees C (thermophilic activity) and 25 degrees C (mesophilic activity). Shifting the peat incubation temperature from 55 to 25 degrees C resulted in a recovery of the mesophilic activity, with a subsequent disappearance of the thermophilic activity. The availability of substrate for bacterial growth varied over time and among different peat samples. To avoid confounding effects of substrate availability, a temperature adaptation index was calculated. This index consisted of the log(10) ratio of TdR incorporation at 55 and 25 degrees C. The temperature index decreased linearly with time, indicating that no thermophilic activity would be detected by the TdR technique 1 month after the temperature downshift. There were no differences between the slopes of the temperature adaptation indices over time for peat samples incubated at 55 degrees C 3 or 11 days before incubation at 25 degrees C. Thus, different levels of bacterial activity did not affect the temperature-driven adaptation of the bacterial community.

Temperature-Driven Adaptation of the Bacterial Community in Peat Measured by Using Thymidine and Leucine Incorporation

PubMed Central

Ranneklev, Sissel Brit; Bååth, Erland

2001-01-01

The temperature-driven adaptation of the bacterial community in peat was studied, by altering temperature to simulate self-heating and a subsequent return to mesophilic conditions. The technique used consisted of extracting the bacterial community from peat using homogenization-centrifugation and measuring the rates of thymidine (TdR) or leucine (Leu) incorporation by the extracted bacterial community at different temperatures. Increasing the peat incubation temperature from 25°C to 35, 45, or 55°C resulted in a selection of bacterial communities whose optimum temperatures for activity correlated to the peat incubation temperatures. Although TdR and Leu incorporations were significantly correlated, the Leu/TdR incorporation ratios were affected by temperature. Higher Leu/TdR incorporation ratios were found at higher temperatures of incubation of the extracted bacterial community. Higher Leu/TdR incorporation ratios were also found for bacteria in peat samples incubated at higher temperatures. The reappearance of the mesophilic community and disappearance of the thermophilic community when the incubation temperature of the peat was shifted down were monitored by measuring TdR incorporation at 55°C (thermophilic activity) and 25°C (mesophilic activity). Shifting the peat incubation temperature from 55 to 25°C resulted in a recovery of the mesophilic activity, with a subsequent disappearance of the thermophilic activity. The availability of substrate for bacterial growth varied over time and among different peat samples. To avoid confounding effects of substrate availability, a temperature adaptation index was calculated. This index consisted of the log10 ratio of TdR incorporation at 55 and 25°C. The temperature index decreased linearly with time, indicating that no thermophilic activity would be detected by the TdR technique 1 month after the temperature downshift. There were no differences between the slopes of the temperature adaptation indices over time for peat samples incubated at 55°C 3 or 11 days before incubation at 25°C. Thus, different levels of bacterial activity did not affect the temperature-driven adaptation of the bacterial community. PMID:11229900

Astronomical Tides and Turbulent Mixing in ROMS/TOMS

DTIC Science & Technology

2007-09-30

46. Carniel, S., L. Kantha, H. Prandke, J. Chiggiato , and M. Sclavo (2006). Turbulence in the Upper Layers of the Southern Adriatic Sea Under Various...H. Prandke, J. Chiggiato , and M. Sclavo (2007). Turbulence in the upper layers of the Southern Adriatic Sea under various meteorological conditions

Specific features of the development of soils of hydromorphic ecosystems in the northern taiga of Western Siberia under conditions of cryogenesis

NASA Astrophysics Data System (ADS)

Matyshak, G. V.; Bogatyrev, L. G.; Goncharova, O. Yu.; Bobrik, A. A.

2017-10-01

Differently directed and heterochronous cryogenic processes have contributed to the contrasting soil cover patterns and spatial heterogeneity of the properties of soils in hydromorphic ecosystems of the discontinuous permafrost zone of the northern taiga in Western Siberia. Frost heave and permafrost thawing within ecosystems of highmoor bogs have led to the development of specific cryogenic landforms, such as flat-topped and large peat mounds. A set of cryogenic soils is developed in these ecosystems; it includes different variants of cryozems, gleyzems (Cryosols), and peat soils (Histosols). The distribution of these soil types is controlled by the local topography and thawing depth, other factors being insignificant. Alternation of peat horizons of different types and ages, whirl-like patterns of horizon boundaries, considerable variations in the thickness of soil horizons, and inversions of soil horizons under the impact of frost cracking, frost heave, and cryoturbation are typical of the considered soils. Thawing depth is the most significant factor affecting the thickness of organic horizons, the soil pH, and the degree of decomposition of peat. As a result of the upward movement of bog ecosystems under the impact of frost heave, peat soils are subjected to considerable transformation: peat horizons undergo mineralization, and the thickness of organic horizons decreases; in some cases, eluvial-illuvial differentiation of the mineral horizons takes place, and peat podzols are developed. However, the opposite process of the return of the soils to the bog stage of pedogenesis with peat accumulation may take place in any time in the case of activation of thermokarst processes.

The Use of Hotspot Spatial Clustering and Multitemporal Satellite Imagery to Facilitate Peat Land Degradation in West Kalimantan, Indonesia (Case Study in Mensiku Miniwatershed of Kapuas River)

NASA Astrophysics Data System (ADS)

Yanuarsyah, I.; Suwarno, Y.; Hudjimartsu, S.

2016-11-01

Peat land in Indonesia is currently a matter of interest to economic activity. In addition to having the uniqueness of the ecosystem which is reserve a huge of biodiversity and carbon storage, peat land is grow an alternative expansion of agriculture and plantation. Mensiku miniwatershed is a subset of Kapuas Watershed with the domination of the peat soil type. It located in the upstream from the Kapuas River and supporting for the continuation of the river ecosystem. The research objective is to facilitate peat land degradation by using hotspot spatial clustering and multitemporal satellite imagery. There have three main processes which are image processing, geoprocessing and statistical process using DBSCAN to determine hotspot clustering. The trend of LUC changes for 14 years (2002 to 2016) shows that the downward occurred in secondary peat forest (0.9% per year) and swampy shrub (0.6% per year). The upward occurred in mixed farms (0.6% per year) and plantations (0.8% per year). degradation rate of peat land over 14 years about 4.6 km2 per year. Hotspot predominantly occurrence in secondary peat forest with 200-250 centimeter depth and Saprists type. DBSCAN clustering obtain 2 clusters in 2002, obtain 4 clusters in 2009 and obtain 1 clusters in 2016. Regarding LUC platform, average density value over 14 years about 0.063 hotspot per km2. DBSCAN is common used to examine the cluster and perform the distribution and density with spatial analysis