Sample records for refractory organic matter

  1. Molecular-level dynamics of refractory dissolved organic matter

    NASA Astrophysics Data System (ADS)

    Niggemann, J.; Gerdts, G.; Dittmar, T.

    2012-04-01

    Refractory dissolved organic matter (DOM) accounts for most of the global oceanic organic carbon inventory. Processes leading to its formation and factors determining its stability are still largely unknown. We hypothesize that refractory DOM carries a universal molecular signature. Characterizing spatial and temporal variability in this universal signature is a key to understanding dynamics of refractory DOM. We present results from a long-term study of the DOM geo-metabolome in the open North Sea. Geo-metabolomics considers the entity of DOM as a population of compounds, each characterized by a specific function and reactivity in the cycling of energy and elements. Ten-thousands of molecular formulae were identified in DOM by ultrahigh resolution mass spectrometry analysis (FT-ICR-MS, Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry). The DOM pool in the North Sea was influenced by a complex interplay of processes that produced, transformed and degraded dissolved molecules. We identified a stable fraction in North Sea DOM with a molecular composition similar to deep ocean DOM. Molecular-level changes in this stable fraction provide novel information on dynamics and interactions of refractory DOM.

  2. Refractory organic matter in coastal salt marshes-effect on C sequestration calculations.

    PubMed

    Leorri, Eduardo; Zimmerman, Andrew R; Mitra, Siddhartha; Christian, Robert R; Fatela, Francisco; Mallinson, David J

    2018-08-15

    The age and ability of salt marshes to accumulate and sequester carbon is often assessed using the carbon isotopic signatures (Δ 14 C and δ 13 C) of sedimentary organic matter. However, transfers of allochthonous refractory carbon (C RF ) from the watershed to marshes would not represent new C sequestration. To better understand how refractory carbon (C RF ) inputs affect assessments of marsh age and C sequestration, Δ 14 C and δ 13 C of both total organic carbon (TOC), C RF , and non-C RF organic matter fractions were measured in salt marshes from four contrasting systems on the North Atlantic coast. To our knowledge, no salt marsh sediment study has considered refractory or allochthonous carbon in carbon budget calculations or the impact on chronologies. Stable and radiogenic isotope data suggest that while TOC was dominated by autochthonous plant inputs, C RF was dominated by locally recycled or allochthonous C, the delivery of which was controlled by the size and slope of each watershed. Steep-gradient rivers analyzed delivered Δ 14 C-depleted C RF to their estuarine marshes, while the site located in the low-gradient river was associated with larger C RF content. Finally, the marsh isolated from riverine input contained the least fraction of TOC as C RF . Laterally transported C RF caused only a small offset in Δ 14 C in relation to TOC in low-gradient systems (average Δ 14 C offset was -44.4 and -24.2‰ at each location). However, the presence of allochthonous Δ 14 C-depleted C RF in sediments of steep-gradient rivers led to large overestimates of the time of organic matter deposition (i.e. apparent age was older than the 'true' time of deposition) (Δ 14 C offset ranged from -170.6 to -528.9‰). Further, reliance on TOC or loss on ignition analyses to calculate C sequestration by marshes might produce overestimates of at least as much as 10 to 20% since neither account for the lateral transport of allochthonous carbon. Copyright © 2018 Elsevier B

  3. Bio-refractory dissolved organic matter and colorants in cassava distillery wastewater: Characterization, coagulation treatment and mechanisms.

    PubMed

    Zhang, Ming; Wang, Zhou; Li, Penghui; Zhang, Hua; Xie, Li

    2017-07-01

    An important portion of organic matter and colorants still remain in the biologically treated distillery wastewater, leaving the dark brown and odorous downstream with the heavy loading of chemical oxygen demand and the potential of forming disinfection byproducts. However, those bio-recalcitrant colorants have not been clearly recognized. The current study investigated the features of the bio-refractory organic matter and colorants in a typical distillery effluent, cassava distillery wastewater; special attention was paid to their change and behaviors in the coagulation treatment following the bio-processes. The wastewater analyses denoted that the fraction of high molecular weight (1-50 kDa and >50 kDa) became predominant after the anaerobic-aerobic processes. Importantly, the lignin breakdown products, melanoidins and lignin phenols were confirmed to be the leading colored components, according to the parallel factor analysis of fluorescence excitation-emission matrixes results. Compared with lignin phenols, the former two types of colorants exhibited stronger bio-refractory activity and resulted in smaller color reduction after the aerobic treatment. Neither advanced oxidation nor adsorption could perform efficiently as post-treatment for decolorization in this study. Nevertheless, high removal of color and dissolved organic matter (∼94.0% and ∼78.3%, respectively) could be achieved by the FeCl 3 -involved coagulation under the optimal conditions. The ferric coagulant was found to preferably interact with the aromatic compounds (such as lignin derivatives) and melanoidins via either surface complexation or electric charge neutralization, or both. The findings presented herein might provide an insight into the evaluation of bio-refractory organic colorants and the Fe(III)-involved decolorization mechanisms of ethanol production wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Synthesis of refractory organic matter in the ionized gas phase of the solar nebula.

    PubMed

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Tissandier, Laurent

    2015-06-09

    In the nascent solar system, primitive organic matter was a major contributor of volatile elements to planetary bodies, and could have played a key role in the development of the biosphere. However, the origin of primitive organics is poorly understood. Most scenarios advocate cold synthesis in the interstellar medium or in the outer solar system. Here, we report the synthesis of solid organics under ionizing conditions in a plasma setup from gas mixtures (H2(O)-CO-N2-noble gases) reminiscent of the protosolar nebula composition. Ionization of the gas phase was achieved at temperatures up to 1,000 K. Synthesized solid compounds share chemical and structural features with chondritic organics, and noble gases trapped during the experiments reproduce the elemental and isotopic fractionations observed in primitive organics. These results strongly suggest that both the formation of chondritic refractory organics and the trapping of noble gases took place simultaneously in the ionized areas of the protoplanetary disk, via photon- and/or electron-driven reactions and processing. Thus, synthesis of primitive organics might not have required a cold environment and could have occurred anywhere the disk is ionized, including in its warm regions. This scenario also supports N2 photodissociation as the cause of the large nitrogen isotopic range in the solar system.

  5. The growth of Scenedesmus quadricauda in RO concentrate and the impacts on refractory organic matter, Escherichia coli, and trace organic compounds.

    PubMed

    Maeng, Sung Kyu; You, Song Hee; Nam, Joo-Youn; Ryu, Hodon; Timmes, Thomas C; Kim, Hyun-Chul

    2018-05-01

    This study achieves a better operational simplicity for the phycoremediation of reverse osmosis (RO) concentrate using Scenedesmus quadricauda microalgae. Under continuous illumination with CO 2 supplementation, algal growth in the RO concentrate resulted in a conversion of polymeric organic matter (a mixture of humic substances and polysaccharides) to biodegradable fractions and their prompt removal along with inorganic nutrients (NO 3 - and PO 4 3- ). The algal-induced degradation of humic-like substances which are typically refractory to microbial decomposition was demonstrated in an indirect manner. In this study, we also investigated the effects of algal treatment on the growth of Escherichia coli and removal of trace organic compounds (TOrCs) from the RO concentrate. Our results indicate that algal treatment of the RO concentrate using aeration with 10% (v/v) CO 2 under continuous illumination is highly feasible as a safe and inexpensive technology to remove non- or slowly-biodegradable organic matter, reduce enteric bacteria, and attenuate TOrCs in wastewater. However, the results should not be generalized, but critically discussed, due to limitations of using the synthetic RO concentrate in evaluating the performance of wastewater remediation with microalgae. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Synthesis of refractory organic matter in the ionized gas phase of the solar nebula

    PubMed Central

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Tissandier, Laurent

    2015-01-01

    In the nascent solar system, primitive organic matter was a major contributor of volatile elements to planetary bodies, and could have played a key role in the development of the biosphere. However, the origin of primitive organics is poorly understood. Most scenarios advocate cold synthesis in the interstellar medium or in the outer solar system. Here, we report the synthesis of solid organics under ionizing conditions in a plasma setup from gas mixtures (H2(O)−CO−N2−noble gases) reminiscent of the protosolar nebula composition. Ionization of the gas phase was achieved at temperatures up to 1,000 K. Synthesized solid compounds share chemical and structural features with chondritic organics, and noble gases trapped during the experiments reproduce the elemental and isotopic fractionations observed in primitive organics. These results strongly suggest that both the formation of chondritic refractory organics and the trapping of noble gases took place simultaneously in the ionized areas of the protoplanetary disk, via photon- and/or electron-driven reactions and processing. Thus, synthesis of primitive organics might not have required a cold environment and could have occurred anywhere the disk is ionized, including in its warm regions. This scenario also supports N2 photodissociation as the cause of the large nitrogen isotopic range in the solar system. PMID:26039983

  7. Land Application of Wastes: An Educational Program. Organic Matter - Module 17, Objectives, and Script.

    ERIC Educational Resources Information Center

    Clarkson, W. W.; And Others

    This module sketches out the impact of sewage organic matter on soils. For convenience, that organic matter is separated into the readily decomposable compounds and the more resistant material (volatile suspended solids, refractory organics, and sludges). The fates of those organics are reviewed along with loading rates and recommended soil…

  8. Natural organic matter properties in Swedish agricultural streams

    NASA Astrophysics Data System (ADS)

    Bieroza, Magdalena; Kyllmar, Katarina; Bergström, Lars; Köhler, Stephan

    2016-04-01

    We have analysed natural organic matter (NOM) properties in 18 agricultural streams in Sweden covering a broad range of environmental (climate, soil type), land use and water quality (nutrient and concentrations, pH, alkalinity) characteristics. Stream water samples collected every two weeks within an ongoing Swedish Monitoring Programme for Agriculture have been analysed for total/dissolved organic carbon, absorbance and fluorescence spectroscopy. A number of quantitative and qualitative spectroscopic parameters was calculated to help to distinguish between terrestrially-derived, refractory organic material and autochthonous, labile material indicative of biogeochemical transformations of terrestrial NOM and recent biological production. The study provides insights into organic matter properties and carbon budgets in agricultural streams and improves understanding of how agricultural catchments transform natural and anthropogenic fluxes of organic matter and nutrients to signals observed in receiving waters.

  9. Evidence of refractory organic matter preserved in the mudstones of Yellowknife Bay and the Murray Formations

    NASA Astrophysics Data System (ADS)

    Eigenbrode, J. L.; Steele, A.; Summons, R. E.; Sutter, B.; McAdam, A.; Franz, H. B.; Mahaffy, P. R.; Conrad, P. G.; Freissinet, C.; Glavin, D. P.; Millan, M.; Ming, D. W.

    2015-12-01

    Volatiles from high-temperature (above 500°C) pyrolysis of drilled and sieved deltaic/lacustrine mudstones at Yellowknife Bay and Pahrump Hills were detected by the Sample Analysis at Mars (SAM) instrument's evolved gas analysis experiment onboard the Curiosity rover in Gale Crater, Mars. Mass fragments detected from the mudstones are consistent with C1-C4 alkyl and single-ring aromatic components that evolve at different temperatures and often in multiple phases. Concurrent release of oxidized sulfur (sulfur dioxide and sulfur trioxide), sulfide gases (hydrogen sulfide, carbonyl sulfide, carbon disulfide, dimethylsulfide or thiol, and thiophene) suggest that either these gases are evolving directly from the mudstone or are products of gas phase reactions in the SAM oven, or both. Multiple chlorohydrocarbon releases are also observed in analysis of the Mojave mudstone indicating punctuated organic releases from the sample. The organic signatures observed are unique to specific samples and are not observed in blanks or all samples, nor can the SAM background explain them. These results suggest that geologically refractory organic matter has been preserved in some Hesperian mudstones despite possible acid-sulfate weathering (as suggested by jarosite in Mojave) and exposure to ionizing cosmic rays after exhumation. We will report on ongoing study of these samples.

  10. Time-resolved analysis of particle emissions from residential biomass combustion - Emissions of refractory black carbon, PAHs and organic tracers

    NASA Astrophysics Data System (ADS)

    Nielsen, Ingeborg E.; Eriksson, Axel C.; Lindgren, Robert; Martinsson, Johan; Nyström, Robin; Nordin, Erik Z.; Sadiktsis, Ioannis; Boman, Christoffer; Nøjgaard, Jacob K.; Pagels, Joakim

    2017-09-01

    Time-resolved particle emissions from a conventional wood stove were investigated with aerosol mass spectrometry to provide links between combustion conditions, emission factors, mixing state of refractory black carbon and implications for organic tracer methods. The addition of a new batch of fuel results in low temperature pyrolysis as the fuel heats up, resulting in strong, short-lived, variable emission peaks of organic aerosol-containing markers of anhydrous sugars, such as levoglucosan (fragment at m/z 60). Flaming combustion results in emissions dominated by refractory black carbon co-emitted with minor fractions of organic aerosol and markers of anhydrous sugars. Full cycle emissions are an external mixture of larger organic aerosol-dominated and smaller thinly coated refractory black carbon particles. A very high burn rate results in increased full cycle mass emission factors of 66, 2.7, 2.8 and 1.3 for particulate polycyclic aromatic hydrocarbons, refractory black carbon, total organic aerosol and m/z 60, respectively, compared to nominal burn rate. Polycyclic aromatic hydrocarbons are primarily associated with refractory black carbon-containing particles. We hypothesize that at very high burn rates, the central parts of the combustion zone become air starved, leading to a locally reduced combustion temperature that reduces the conversion rates from polycyclic aromatic hydrocarbons to refractory black carbon. This facilitates a strong increase of polycyclic aromatic hydrocarbons emissions. At nominal burn rates, full cycle emissions based on m/z 60 correlate well with organic aerosol, refractory black carbon and particulate matter. However, at higher burn rates, m/z 60 does not correlate with increased emissions of polycyclic aromatic hydrocarbons, refractory black carbon and organic aerosol in the flaming phase. The new knowledge can be used to advance source apportionment studies, reduce emissions of genotoxic compounds and model the climate impacts of

  11. Natural organic matter properties in Swedish agricultural streams

    NASA Astrophysics Data System (ADS)

    Bieroza, Magdalena; Kyllmar, Katarina; Bergström, Lars; Köhler, Stephan

    2017-04-01

    The following paper shows natural organic matter (NOM) properties of stream water samples collected from 8 agricultural streams and 12 agricultural observational fields in Sweden. The catchments and observational fields cover a broad range of environmental (climate, soil type), land use and water quality (nutrient and concentrations, pH, alkalinity) characteristics. Stream water samples collected every two weeks within an ongoing Swedish Monitoring Programme for Agriculture have been analysed for total/dissolved organic carbon, absorbance and fluorescence spectroscopy. A number of quantitative and qualitative spectroscopic parameters was calculated to help to distinguish between terrestrially-derived, refractory organic material and autochthonous, labile material indicative of biogeochemical transformations of terrestrial NOM and recent biological production. The study provides insights into organic matter properties and carbon budgets in agricultural streams and improves understanding of how agricultural catchments transform natural and anthropogenic fluxes of organic matter and nutrients. The insights from the grab sampling are supported by high-frequency turbidity, fulvic-like and tryptophan-like fluorescence measurements with in situ optical sensor.

  12. Dissolved organic matter in anoxic pore waters from Mangrove Lake, Bermuda

    USGS Publications Warehouse

    Orem, W.H.; Hatcher, P.G.; Spiker, E. C.; Szeverenyi, N.M.; Maciel, G.E.

    1986-01-01

    Dissolved organic matter and dissolved inorganic chemical species in anoxic pore water from Mangrove Lake, Bermuda sediments were studied to evaluate the role of pore water in the early diagenesis of organic matter. Dissolved sulphate, titration alkalinity, phosphate, and ammonia concentration versus depth profiles were typical of many nearshore clastic sediments and indicated sulphate reduction in the upper 100 cm of sediment. The dissolved organic matter in the pore water was made up predominantly of large molecules, was concentrated from large quantities of pore water by using ultrafiltration and was extensively tudied by using elemental and stable carbon isotope analysis and high-resolution, solid state 13C nuclear magnetic resonance and infrared spectroscopy. The results indicate that this material has a predominantly polysaccharide-like structure and in addition contains a large amount of oxygen-containing functional groups (e.g., carboxyl groups). The 13C nulcear magnetic resonance spectra of the high-molecular-weight dissolved organic matter resemble those of the organic matter in the surface sediments of Mangrove Lake. We propose that this high-molecular-weight organic matter in pore waters represents the partially degraded, labile organic components of the sedimentary organic matter and that pore waters serve as a conduit for removal of these labile organic components from the sediments. The more refractory components are, thus, selectively preserved in the sediments as humic substances (primarily humin). ?? 1986.

  13. Turnover time of fluorescent dissolved organic matter in the dark global ocean.

    PubMed

    Catalá, Teresa S; Reche, Isabel; Fuentes-Lema, Antonio; Romera-Castillo, Cristina; Nieto-Cid, Mar; Ortega-Retuerta, Eva; Calvo, Eva; Álvarez, Marta; Marrasé, Cèlia; Stedmon, Colin A; Álvarez-Salgado, X Antón

    2015-01-29

    Marine dissolved organic matter (DOM) is one of the largest reservoirs of reduced carbon on Earth. In the dark ocean (>200 m), most of this carbon is refractory DOM. This refractory DOM, largely produced during microbial mineralization of organic matter, includes humic-like substances generated in situ and detectable by fluorescence spectroscopy. Here we show two ubiquitous humic-like fluorophores with turnover times of 435±41 and 610±55 years, which persist significantly longer than the ~350 years that the dark global ocean takes to renew. In parallel, decay of a tyrosine-like fluorophore with a turnover time of 379±103 years is also detected. We propose the use of DOM fluorescence to study the cycling of resistant DOM that is preserved at centennial timescales and could represent a mechanism of carbon sequestration (humic-like fraction) and the decaying DOM injected into the dark global ocean, where it decreases at centennial timescales (tyrosine-like fraction).

  14. Biodegradability of algal-derived organic matter in a large artificial lake by using stable isotope tracers.

    PubMed

    Lee, Yeonjung; Lee, Bomi; Hur, Jin; Min, Jun-Oh; Ha, Sun-Yong; Ra, Kongtae; Kim, Kyung-Tae; Shin, Kyung-Hoon

    2016-05-01

    In order to understand the biodegradability of algal-derived organic matter, biodegradation experiments were conducted with (13)C and (15)N-labeled natural phytoplankton and periphytic algal populations in experimental conditions for 60 days. Qualitative changes in the dissolved organic matter were also determined using parallel factor analysis and the stable carbon isotopic composition of the hydrophobic dissolved organic matter through the experimental period. Although algal-derived organic matter is considered to be easily biodegradable, the initial amounts of total organic carbon newly produced by phytoplankton and periphytic algae remained approximately 16 and 44 % after 60 days, respectively, and about 22 and 43 % of newly produced particulate nitrogen remained. Further, the dissolved organic carbon derived from both algal populations increased significantly after 60 days. Although the dissolved organic matter gradually became refractory, the contributions of the algal-derived organic matter to the dissolved organic matter and hydrophobic dissolved organic matter increased. Our laboratory experimental results suggest that algal-derived organic matter produced by phytoplankton and periphytic algae could contribute significantly to the non-biodegradable organic matter through microbial transformations.

  15. Identification of Reactive and Refractory Components of Dissolved Organic Nitrogen by FT-ICR Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Cooper, W. T.; Podgorski, D. C.; Osborne, D. M.; Corbett, J.; Chanton, J.

    2010-12-01

    Dissolved organic nitrogen is an often overlooked but potentially significant bioavailable component of dissolved organic matter. Studies of bulk DON turnover have been reported, but the compositions of the reactive and refractory components of DON are largely unknown. Here we show the unique ability of atmospheric pressure photoionization (APPI) coupled to ultrahigh resolution mass spectrometry to identify the reactive and refractory components of DON. Figure 1 is an isolated 0.30 m/z window from an ultrahigh resolution APPI FT-ICR mass spectrum of DON in surface waters draining an agricultural area in South Florida. Using this optimized, negative-ion APPI strategy we have been able to identify the reactive and refractory components of DON in these nitrogen-rich waters. Similar results were observed with samples from soil porewaters in sedge-dominated fens and sphagnum-dominated bogs within the Glacial Lake Agassiz Peatlands (GLAP) of northern Minnesota. Surprisingly, microbes appear to initially use similar enzymatic pathways to degrade DON and DOC, often with little release of nitrogen. Figure 1. Isolated 0.30 m/z window at nominal mass 432 from negative-ion APPI FT-ICR mass spectrum of DOM from waters draining an agricultural area in South Florida. Peaks marked contain nitrogen.

  16. Water repellency and organic matter composition after a wildfire: new insights using thermal analysis

    NASA Astrophysics Data System (ADS)

    Neris, Jonay; Doerr, Stefan

    2014-05-01

    Water repellency, a key parameter in the hydrological and ecological behaviour of ecosystems, is one of the main soil properties affected by wildfire through its impact on organic matter (Shakesby and Doerr, 2006). This study examines the link between post-fire organic matter quantity and composition, soil water repellency and related hydrological properties in order to (i) examine the influence of different organic matter pools on soil hydrological properties and (ii) to explore the use of these links as a proxy for soil hydrological impacts of fire. Soil samples from five fire-affected burned and unburned control sites in Andisols terrain in Tenerife, previously studied for water repellency and hydrology-related properties (Neris et al., 2013), were selected and thermogravimetric analysis (TG) carried out to evaluate fire impacts on their organic matter composition. A decrease in the organic matter quantity as well as in the relative amount of the labile organic matter pool and an increase in the recalcitrant and/or refractory pool depending was observed in the burned soils. TG data, using 10 ºC temperature range steps, allowed reasonable prediction of soil properties evaluated, with R2 ranging from 0.4 to 0.8. The labile pool showed a broad and positive influence on most soil properties evaluated, whereas the refractory pool and the dehydration range affected the surface water holding capacity and water repellency. These results, in conjunction with the simplicity of the TG analysis suggest that, following a calibration step to link TG data to the site-specific post-fire soil properties, this method may be a useful tool for rapid and cost-effective soil hydrological response evaluation after the fire. References Neris, J., Tejedor, M., Fuentes, J., Jiménez, C., 2013. Infiltration, runoff and soil loss in Andisols affected by forest fire (Canary Islands, Spain). Hydrological Processes 27(19), 2814-2824. Shakesby, R.A., Doerr, S.H., 2006. Wildfire as a

  17. Origin of cometary and chondritic refractory organics: Ion irradiation experiments

    NASA Astrophysics Data System (ADS)

    Quirico, E.; Faure, M.; Faure, A.; Baklouti, D.; Boduch, P.; Rothard, H.; Ballanzat, E.; Dartois, E.; Brunetto, R.; Bonal, L.; Beck, P.; Schmitt, B.; Duprat, J.; Engrand, C.

    2017-09-01

    The formation process of Refractory Organic matter present in chondrites and Interplanetary Dust Particles (IDPs) of cometary and asteroidal origin is a debated issue. Earlier studies have advocated a formation step in a hot environment, however the potential role of ion irradiation has been so far poorly constrained. We present here experimental simulations that address this issue, comprising thermal degradation and ion irradiation experiments conducted at GANIL (Caen France) and CSNSM (Orsay France). We show that unlike thermal reactions, ion irradiation might lead to ROM-like material under very stringent conditions on both the nuclear dose and the nature of precursor. These very narrow conditions suggest that forming ROM without any action of thermal reactions is extremely difficult in astrophysical environments, either ISM or the proto-solar disk.

  18. Amino Acid Enantiomeric Ratios in Semi-Labile vs. Refractory Dissolved Organic Matter: Implications for a Microbial N Pump

    NASA Astrophysics Data System (ADS)

    Bour, A. L.; Broek, T.; Gier, E. J.; Mccarthy, M. D.

    2016-02-01

    Microbes are key moderators in the cycling of marine dissolved organic matter (DOM), most of which remains unidentifiable at the molecular level. A major current question, however, is to what degree heterotrophic bacteria directly mediate C and N sequestration in the deep sea. Amino acids (AA) represent almost all organic N that can be identified at the molecular level, while D-AA enantiomers represent unique source-specific biomarkers for prokaryotes, known to be highly enriched in ocean DOM. If increasing bacterial-sourced material ultimately leads to millennial scale sequestration of refractory DOM (RDOM), then one would expect a clear correlation between bacterial biomarkers and DOM radiocarbon (Δ14C) ages, in particular in the deep sea. Here we directly test this idea for the first time, by measuring D-AA abundance and distribution in isolated Δ14C young vs. old DOM from the central north pacific gyre. We used a coupled ultrafiltration/solid phase extraction approach to isolate semi-labile vs. RDOM, based on known molecular weight and Δ14C age correlations. The Δ14C ages of isolated material ranged from 205-275 ybp for surface semi-labile DOM, to 6680-6740 ybp for deep ocean RDOM. We measured enantiomeric (D/L) AA ratios, as well as AA molar percentages to estimate traditional degradation parameters (DI and RI), in semi-labile vs. RDOM fractions from the surface to deep ocean at HOT, Station ALOHA. We interpret our results in terms of the hypothesis of a microbial N pump, examining the similarity of microbial source signatures (D/L distributions) and calculated organic N contributions from heterotrophic bacteria, in the context of the Δ14C age of each fraction. Finally, we also evaluate these data vs. common AA molar percentage based indices of degradation.

  19. Characterization and source identification of organic matter in view of land uses and heavy rainfall in the Lake Shihwa, Korea.

    PubMed

    Lee, Yeonjung; Hur, Jin; Shin, Kyung-Hoon

    2014-07-15

    The characteristics and sources of organic matter in water of the Lake Shihwa, which receives inputs from rural, urban, and industrial areas, were evaluated by examining the biodegradable organic carbon concentration, fluorescence spectra, and carbon and nitrogen isotope ratios, especially during rainy season and dry season. The organic matter transported from rural areas was of refractory nature, while that of industrial origin decomposed rapidly. As compared to the dry season, the organic matter in the rainy season was characterized by a reduced labile fraction. During the dry season, the autochthonous organic matter dominated in the lake, however, the contributions of allochthonous organic sources by industrial and rural areas significantly increased at rainy season. This investigation revealed that the transport of organic matter of anthropogenic origin to the Lake Shihwa was mainly influenced by heavy rainfall. Moreover, each anthropogenic source could differently influence the occurrence of organic matter in water of the Lake Shihwa. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. INTERACTIONS BETWEEN PHOTOCHEMICAL AND MICROBIAL DECOMPOSITION IN MODIFYING THE BIOLOGICAL AVAILABILITY AND OPTICAL PROPERTIES OF ESTUARINE DISSOLVED ORGANIC MATTER

    EPA Science Inventory

    Direct photodecomposition and photochemically-mediated bacterial degradation (via photochemical modification of otherwise refractory DOM into biologically labile forms) provide
    important pathways for the loss of dissolved organic matter in coastal waters. Here we report
    lab...

  1. Investigating microbial cycling of recalcitrant organic matter in marine sediments using natural isotope respirometry in a novel, carbon-free bioreactor

    NASA Astrophysics Data System (ADS)

    Mahmoudi, N.; Beaupre, S. R.; Pearson, A.

    2016-02-01

    Marine sediments harbor complex microbial communities that play a key role in the cycling of carbon and nutrients. Reactions initiated by microbial enzymes at the molecular scale drive the rate and extent of organic matter degradation to CO2 and CH4. Organic matter is comprised of multiple carbon pools with different intrinsic turnover times. It is hypothesized that microbes will degrade younger pools with more labile compounds, while older pools with refractory compounds will remain unutilized. However, many studies have shown that microbes are capable of respiring older, refractory pools of organic matter in a number of environments. In order to better understand microbial carbon cycling and the fate of recalcitrant organic matter, we constructed a novel bioreactor system to measure carbon isotopes during microbial degradation of complex organic matter. This system enables us to measure the natural isotopic signature (δ13C and Δ14C ) of microbially-respired CO2, thereby allowing us to determine the age of the organic matter that is being respired. We investigated microbial carbon utilization in sediments from Falmouth, MA and observed a pattern of successive microbial respiration such that several peaks appear over the course of a 7-day incubation. Δ14C signatures of CO2 fractions collected during incubation ranged from -185 to +70‰ with the majority of CO2 appearing to be modern. This indicates that the microbial community is primarily are respiring labile organic matter from fast cycling pools. Interestingly, the observation of multiple peaks with similar Δ14C signatures suggests that organic matter is degraded in a step-wise manner by a succession of microbial taxa. Illumina sequencing of 16S rRNA genes will identify these successions of bacteria (and archaea), while enzymatic analyses may help determine the metabolic pathways that correspond to each peak. Our study will provide a molecular-level framework for organic matter degradation and provide

  2. Organic matter degradation in surface sediments of the Changjiang estuary: Evidence from amino acids.

    PubMed

    Wang, Kui; Chen, Jianfang; Jin, Haiyan; Li, Hongliang; Zhang, Weiyan

    2018-05-12

    Organic matter degradation is a key component of the processes of carbon preservation and burial in seafloor sediments. The aim of this study was to explore organic matter degradation state within the open-shelf Changjiang Estuary of the East China Sea, using an amino acids-based degradation index (DI) in conjunction with information about organic matter source (marine versus terrestrial), bottom water oxygenation state, and sediment grain size. The relative molar percentages of 17 individual amino acids (characterized using principal component analysis) in surface sediments indicate that organic matter is degraded to varying extents across the estuary seabed. Sediments with DI >0 (relatively labile) were found mostly within a coastal hypoxic area. Sediments of DI less than -1 (relatively refractory) were found near the Changjiang River mouth and the northern and southern parts of the central shelf. We consider DI to be a more reliable indicator of degradation than simple ratios of AAs. DI was inversely correlated with the proportion of terrestrial organic material (F t ) in the sediments, indicating that relatively fresh/labile organic matter was generally associated with marine sources. DI was significantly correlated with F t and bottom water apparent oxygen utilization (AOU bot ) together. The parameter DI and the (labile) amino acid tyrosine were highest in hypoxic areas, suggesting the presence of relatively fresh organic matter, probably due to a combination of marine-source inputs and better preservation of organic matter in the silt and clay sediments of these areas (as compared to sandy sediments). Less degraded organic matter with high amino acids was also favorable to benthic animals. Overall, sedimentary estuarine organic matter was least degraded in areas characterized by marine sources of organic matter, low-oxygen conditions, and fine-grained sediments. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Production of fluorescent dissolved organic matter in Arctic Ocean sediments.

    PubMed

    Chen, Meilian; Kim, Ji-Hoon; Nam, Seung-Il; Niessen, Frank; Hong, Wei-Li; Kang, Moo-Hee; Hur, Jin

    2016-12-16

    Little is known about the production of fluorescent dissolved organic matter (FDOM) in the anoxic oceanic sediments. In this study, sediment pore waters were sampled from four different sites in the Chukchi-East Siberian Seas area to examine the bulk dissolved organic carbon (DOC) and their optical properties. The production of FDOM, coupled with the increase of nutrients, was observed above the sulfate-methane-transition-zone (SMTZ). The presence of FDOM was concurrent with sulfate reduction and increased alkalinity (R 2  > 0.96, p < 0.0001), suggesting a link to organic matter degradation. This inference was supported by the positive correlation (R 2  > 0.95, p < 0.0001) between the net production of FDOM and the modeled degradation rates of particulate organic carbon sulfate reduction. The production of FDOM was more pronounced in a shallow shelf site S1 with a total net production ranging from 17.9 to 62.3 RU for different FDOM components above the SMTZ depth of ca. 4.1 mbsf, which presumably underwent more accumulation of particulate organic matter than the other three deeper sites. The sediments were generally found to be the sources of CDOM and FDOM to the overlying water column, unearthing a channel of generally bio-refractory and pre-aged DOM to the oceans.

  4. Production of fluorescent dissolved organic matter in Arctic Ocean sediments

    NASA Astrophysics Data System (ADS)

    Chen, Meilian; Kim, Ji-Hoon; Nam, Seung-Il; Niessen, Frank; Hong, Wei-Li; Kang, Moo-Hee; Hur, Jin

    2016-12-01

    Little is known about the production of fluorescent dissolved organic matter (FDOM) in the anoxic oceanic sediments. In this study, sediment pore waters were sampled from four different sites in the Chukchi-East Siberian Seas area to examine the bulk dissolved organic carbon (DOC) and their optical properties. The production of FDOM, coupled with the increase of nutrients, was observed above the sulfate-methane-transition-zone (SMTZ). The presence of FDOM was concurrent with sulfate reduction and increased alkalinity (R2 > 0.96, p < 0.0001), suggesting a link to organic matter degradation. This inference was supported by the positive correlation (R2 > 0.95, p < 0.0001) between the net production of FDOM and the modeled degradation rates of particulate organic carbon sulfate reduction. The production of FDOM was more pronounced in a shallow shelf site S1 with a total net production ranging from 17.9 to 62.3 RU for different FDOM components above the SMTZ depth of ca. 4.1 mbsf, which presumably underwent more accumulation of particulate organic matter than the other three deeper sites. The sediments were generally found to be the sources of CDOM and FDOM to the overlying water column, unearthing a channel of generally bio-refractory and pre-aged DOM to the oceans.

  5. Production of fluorescent dissolved organic matter in Arctic Ocean sediments

    PubMed Central

    Chen, Meilian; Kim, Ji-Hoon; Nam, Seung-Il; Niessen, Frank; Hong, Wei-Li; Kang, Moo-Hee; Hur, Jin

    2016-01-01

    Little is known about the production of fluorescent dissolved organic matter (FDOM) in the anoxic oceanic sediments. In this study, sediment pore waters were sampled from four different sites in the Chukchi-East Siberian Seas area to examine the bulk dissolved organic carbon (DOC) and their optical properties. The production of FDOM, coupled with the increase of nutrients, was observed above the sulfate-methane-transition-zone (SMTZ). The presence of FDOM was concurrent with sulfate reduction and increased alkalinity (R2 > 0.96, p < 0.0001), suggesting a link to organic matter degradation. This inference was supported by the positive correlation (R2 > 0.95, p < 0.0001) between the net production of FDOM and the modeled degradation rates of particulate organic carbon sulfate reduction. The production of FDOM was more pronounced in a shallow shelf site S1 with a total net production ranging from 17.9 to 62.3 RU for different FDOM components above the SMTZ depth of ca. 4.1 mbsf, which presumably underwent more accumulation of particulate organic matter than the other three deeper sites. The sediments were generally found to be the sources of CDOM and FDOM to the overlying water column, unearthing a channel of generally bio-refractory and pre-aged DOM to the oceans. PMID:27982085

  6. Effect of a seasonal diffuse pollution migration on natural organic matter behavior in a stratified dam reservoir.

    PubMed

    Yu, Soon Ju; Lee, Jae Yil; Ha, Sung Ryong

    2010-01-01

    This article aims to describe the influence of diffuse pollution on the temporal and spatial characteristics of natural organic matter (NOM) in a stratified dam reservoir, the Daecheong Dam, on the basis of intensive observation results and the dynamic water quality simulation using CE-QUAL-W2. Turbidity is regarded as a comprehensive representation of allochothonous organic matter from diffuse sources in storm season because the turbidity concentration showed reasonable significance in a statistical correlation with the UV absorbance at 254 nm and total phosphorus. CE-QUAL-W2 simulation results showed good consistency with the observed data in terms of dissolved organic matter (DOM) including refractory dissolved organic carbon (RDOC) and labile DOC and also well explained the internal movement of constituents and stratification phenomenon in the reservoir. Instead turbidity and NOM were related well in the upper region of the reservoir according to flow distance, gradually as changing to dissolved form of organic matter, RDOM affected organic matter concentration of reservoir water quality compared to turbidity. To control the increase of soluble organic matters in the dam reservoir, appropriate dam water discharge gate operation provided effective measurement. Because of the gate operation let avoid the accumulation of organic matter within a dam reservoir by shorten of turbid regime retention time.

  7. Experimental evidence for an effect of early-diagenetic interaction between labile and refractory marine sedimentary organic matter on nitrogen dynamics

    NASA Astrophysics Data System (ADS)

    Turnewitsch, Robert; Domeyer, Bettina; Graf, Gerhard

    2007-05-01

    In most natural sedimentary systems labile and refractory organic material (OM) occur concomitantly. Little, however, is known on how different kinds of OM interact and how such interactions affect early diagenesis in sediments. In a simple sediment experiment, we investigated how interactions of OM substrates of different degradability affect benthic nitrogen (N) dynamics. Temporal evolution of a set of selected biogeochemical parameters was monitored in sandy sediment over 116 days in three experimental set-ups spiked with labile OM (tissue of Mytilus edulis), refractory OM (mostly aged Zostera marina and macroalgae), and a 1:1 mixture of labile and refractory OM. The initial amounts of particulate organic carbon (POC) were identical in the three set-ups. To check for non-linear interactions between labile and refractory OM, the evolution of the mixture system was compared with the evolution of the simple sum of the labile and refractory systems, divided by two. The sum system is the experimental control where labile and refractory OM are virtually combined but not allowed to interact. During the first 30 days there was evidence for net dissolved-inorganic-nitrogen (DIN) production followed by net DIN consumption. (Here 'DIN' is the sum of ammonium, nitrite and nitrate.) After ˜ 30 days a quasi steady state was reached. Non-linear interactions between the two types of OM were reflected by three main differences between the early-diagenetic evolutions of nitrogen dynamics of the mixture and sum (control) systems: (1) In the mixture system the phases of net DIN production and consumption commenced more rapidly and were more intense. (2) The mixture system was shifted towards a more oxidised state of DIN products [as indicated by increased (nitrite + nitrate)/(ammonium) ratios]. (3) There was some evidence that more OM, POC and particulate nitrogen were preserved in the mixture system. That is, in the mixture system more particulate OM was preserved while a higher

  8. Redox effects on the microbial degradation of refractory organic matter in marine sediments

    NASA Astrophysics Data System (ADS)

    Reimers, Clare E.; Alleau, Yvan; Bauer, James E.; Delaney, Jennifer; Girguis, Peter R.; Schrader, Paul S.; Stecher, Hilmar A.

    2013-11-01

    Microbially mediated reduction-oxidation (redox) reactions are often invoked as being the mechanisms by which redox state influences the degradation of sedimentary organic matter (OM) in the marine environment. To evaluate the effects of elevated, oscillating and reduced redox potentials on the fate of primarily aged, mineral-adsorbed OM contained in continental shelf sediments, we used microbial fuel cells to control redox state within and around marine sediments, without amending the sediments with reducing or oxidizing substances. We subsequently followed electron fluxes in the redox elevated and redox oscillating treatments, and related sediment chemical, isotopic and bacterial community changes to redox conditions over a 748-day experimental period. The electron fluxes of the elevated and oscillating redox cells were consistent with models of organic carbon (OC) oxidation with time-dependent first-order rate constants declining from 0.023 to 0.005 y-1, in agreement with rate constants derived from typical OC profiles and down core ages of offshore sediments, or from sulfate reduction rate measurements in similar sediments. Moreover, although cumulative electron fluxes were higher in the continuously elevated redox treatment, incremental rates of electron harvesting in the two treatments converged over the 2 year experiment. These similar rates were reflected in chemical indicators of OM metabolism such as dissolved OC and ammonia, and particulate OC concentrations, which were not significantly different among all treatments and controls over the experimental time-scale. In contrast, products of carbonate and opal dissolution and metal mobilization showed greater enrichments in sediments with elevated and oscillating redox states. Microbial community composition in anode biofilms and surrounding sediments was assessed via high-throughput 16S rRNA gene sequencing, and these analyses revealed that the elevated and oscillatory redox treatments led to the

  9. Degradation of refractory organics in biotreated landfill leachate using high voltage pulsed discharge combined with TiO2.

    PubMed

    Zhang, Cheng; Liu, Jianyong; Yang, Xiaojian; Cao, Weimin; Qian, Guangren

    2017-03-15

    The effect of high voltage pulsed discharge (HVPD) combined with TiO 2 on the degradation of refractory organic compounds in actual biotreated landfill leachate was investigated. The optimal chemical oxygen demand (COD) removal efficiency could achieve to 58.9% using HVPD+TiO 2 within 30min at 40kV, 400Hz, and the conductivity of 4.05mscm -1 in gas-liquid pulsed discharge. The aromatic compounds decreased by 33.6% compared with HVPD alone according to the UV absorbance at 254nm. Moreover, the fluorescence intensity of humic and fulvic substances was greatly decreased. Active species such as OH radical and H 2 O 2 were enhanced in the presence of TiO 2 , resulting in more high molecular weight organic matter into small molecules or mineralized. In addition, possible degradation pathways was proposed based on acetophenone, which is effective for the degradation of organic matter in biotreated landfill leachate as long as the active species increased. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. TOWARD THE FORMATION OF CARBONACEOUS REFRACTORY MATTER IN HIGH TEMPERATURE HYDROCARBON-RICH ATMOSPHERES OF EXOPLANETS UPON MICROMETEOROID IMPACT

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

    Dangi, Beni B.; Kim, Yong S.; Krasnokutski, Serge A.

    2015-05-20

    We report on laboratory simulation experiments mimicking the chemical processing of model atmospheres of exoplanets containing C3 and C4 hydrocarbons at moderate temperatures of 400 K upon interaction of catalytic surfaces of micrometeoroids. By utilizing an ultrasonic levitator device and heating singly levitated particles under simulated microgravity conditions, Raman spectroscopy is utilized as a non-invasive tool to probe on line and in situ the conversion of C3 and C4 hydrocarbons to refractory carbonaceous matter on the surfaces of levitated particles. Secondary Ion Mass Spectrometry and electron microscopic imaging were also conducted to gain further insight into the elementary composition andmore » structures of the refractories formed. Our results provide compelling evidence that in the presence of a catalytic surface, which can be supplied in the form of micrometeoroids and atmospheric dust particles, hydrocarbon gases present in the atmospheres of exoplanets can be converted to refractory, carbon-rich carbonaceous matter of mainly graphitic structure with a carbon content of at least 90% at elevated temperatures. This finding might explain the low methane to carbon monoxide (CH{sub 4}–CO) ratio in the hot Neptune GJ 436b, where the abundant methane photochemically converts to higher order hydrocarbons and ultimately to refractory graphite-like carbon in the presence of a silicon surface.« less

  11. Influence of sediment-organic matter quality on growth and polychlorobiphenyl bioavailability in Echinodermata (Amphiura filiformis)

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

    Gunnarsson, J.S.; Granberg, M.E.; Nilsson, H.C.

    Sediment total organic carbon (TOC) content is considered to be a primary food source for benthic invertebrates and a major factor influencing the partitioning and bioavailability of sediment-associated organic contaminants. Most studies report that both toxicity and uptake of sediment-associated contaminants by benthic organisms are inversely proportional to sediment TOC content. The aim of this study was to determine the importance of the TOC quality for the bioavailability of sediment-associated organic contaminants and the growth of benthic macrofauna. The common infaunal brittle star Amphiura filiformis was exposed to a base sediment covered by a {sup 14}C-polychlorobipenyl (3,3{prime}4,4{prime}-{sup 14}C-tetrachlorobiphenyl (TCB)) contaminatedmore » top layer (0--2 cm), enriched to the same TOC content with 31 g TOC/m{sup 2} of different quality and origin. The following carbon sources, ranging from labile to refractory, were used: (1) green macroalga (Ulva lactuca), (2) brown macroalga (Ascophyllum nodosum), (3) eelgrass (Zostera Marina), (4) phytoplankton (Ceratium spp.), and (5) lignins of terrestrial origin. Characterization of the organic matter quality was accomplished by measuring the content of amino acids, lipids, C, N, and polyphenolic compounds. The reactivity of the sedimentary organic matter was assessed by means of respiration and dissolved inorganic nitrogen flux measurements. The experiment was carried out in 1-L glass jars, each containing four brittle stars and the contaminated and enriched sediment. The jars were circulated in a flow-through mode with filtered seawater. Somatic growth (regeneration of a precut arm) and bioaccumulation of {sup 14}C-TCB were measured at 10 sampling occasions during 48 d of exposure. Growth rates, TCB uptake rates, and steady-state concentrations differed significantly between treatments and were correlated to the qualities of the organic substrates. The greatest TCB accumulation and growth were observed in

  12. soil organic matter fractionation

    NASA Astrophysics Data System (ADS)

    Osat, Maryam; Heidari, Ahmad

    2010-05-01

    Carbon is essential for plant growth, due to its effects on other soil properties like aggregation. Knowledge of dynamics of organic matter in different locations in the soil matrix can provide valuable information which affects carbon sequestration and soil the other soil properties. Extraction of soil organic matter (SOM) fractions has been a long standing approach to elucidating the roles of soil organic matter in soil processes. Several kind fractionation methods are used and all provide information on soil organic matter function. Physical fractionation capture the effects on SOM dynamics of the spatial arrangement of primary and secondary organomineral particles in soil while chemical fractionation can not consider the spatial arrangement but their organic fractions are suitable for advanced chemical characterization. Three method of physical separation of soil have been used, sieving, sedimentation and densitometry. The distribution of organic matter within physical fractions of the soil can be assessed by sieving. Sieving separates soil particles based strictly on size. The study area is located on north central Iran, between 35° 41'- 36° 01' N and 50° 42'- 51° 14' E. Mean annual precipitation about 243.8 mm and mean annual air temperature is about 14.95 °C. The soil moisture and temperature regime vary between aridic-thermic in lower altitudes to xeric-mesic in upper altitudes. More than 36 surface soil samples (0-20 cm) were collected according to land-use map units. After preliminary analyzing of samples 10 samples were selected for further analyses in five size fractions and three different time intervals in September, January and April 2008. Fractionation carried out by dry sieving in five classes, 1-2 mm, 0.5-1 mm, 270 μm-0.5mm, 53-270 μm and <53 μm. Organic matter and C/N ratio were determined for all fractions at different time intervals. Chemical fractionation of organic matter also carried out according to Tan (2003), also Mineralogical

  13. Molecular characterization of dissolved organic matter (DOM): a critical review.

    PubMed

    Nebbioso, Antonio; Piccolo, Alessandro

    2013-01-01

    Advances in water chemistry in the last decade have improved our knowledge about the genesis, composition, and structure of dissolved organic matter, and its effect on the environment. Improvements in analytical technology, for example Fourier-transform ion cyclotron (FT-ICR) mass spectrometry (MS), homo and hetero-correlated multidimensional nuclear magnetic resonance (NMR) spectroscopy, and excitation emission matrix fluorimetry (EEMF) with parallel factor (PARAFAC) analysis for UV-fluorescence spectroscopy have resulted in these advances. Improved purification methods, for example ultrafiltration and reverse osmosis, have enabled facile desalting and concentration of freshly collected DOM samples, thereby complementing the analytical process. Although its molecular weight (MW) remains undefined, DOM is described as a complex mixture of low-MW substances and larger-MW biomolecules, for example proteins, polysaccharides, and exocellular macromolecules. There is a general consensus that marine DOM originates from terrestrial and marine sources. A combination of diagenetic and microbial processes contributes to its origin, resulting in refractory organic matter which acts as carbon sink in the ocean. Ocean DOM is derived partially from humified products of plants decay dissolved in fresh water and transported to the ocean, and partially from proteinaceous and polysaccharide material from phytoplankton metabolism, which undergoes in-situ microbial processes, becoming refractory. Some of the DOM interacts with radiation and is, therefore, defined as chromophoric DOM (CDOM). CDOM is classified as terrestrial, marine, anthropogenic, or mixed, depending on its origin. Terrestrial CDOM reaches the oceans via estuaries, whereas autochthonous CDOM is formed in sea water by microbial activity; anthropogenic CDOM is a result of human activity. CDOM also affects the quality of water, by shielding it from solar radiation, and constitutes a carbon sink pool. Evidence in support

  14. Source analysis of organic matter in swine wastewater after anaerobic digestion with EEM-PARAFAC.

    PubMed

    Zeng, Zhuo; Zheng, Ping; Ding, Aqiang; Zhang, Meng; Abbas, Ghulam; Li, Wei

    2017-03-01

    Swine wastewater is one of the most serious pollution sources, and it has attracted a great public concern in China. Anaerobic digestion technology is extensively used in swine wastewater treatment. However, the anaerobic digestion effluents are difficult to meet the discharge standard. The results from batch experiments showed that plenty of refractory organic matter remained in the effluents after mesophilic anaerobic digestion for 30 days. The effluent total COD (tCOD) and soluble COD (sCOD) were 483 and 324 mg/L, respectively, with the sCOD/tCOD ratio of 0.671. Fluorescence excitation-emission matrix (EEM) coupled with parallel factor analysis (PARAFAC) revealed that the dissolved organic matter in the effluents was tryptophan-like substance, humic acid substance, and fulvic acid substance. Based on the appearance time during anaerobic digestion, tryptophan-like substance and humic acid substance were inferred to originate from the raw swine wastewater, and the fulvic acid substance was inferred to be formed in the anaerobic digestion. This work has revealed the source of residual organic matter in anaerobic digestion of swine wastewater and has provided some valuable information for the post-treatment.

  15. Radiocarbon (14C) Constraints On The Fraction Of Refractory Dissolved Organic Carbon In Primary Marine Aerosol From The Northwest Atlantic

    NASA Astrophysics Data System (ADS)

    Beaupre, S. R.; Kieber, D. J.; Keene, W. C.; Long, M. S.; Frossard, A. A.; Kinsey, J. D.; Duplessis, P.; Chang, R.; Maben, J. R.; Lu, X.; Zhu, Y.; Bisgrove, J.

    2017-12-01

    Nearly all organic carbon in seawater is dissolved (DOC), with more than 95% considered refractory based on modeled average lifetimes ( 16,000 years) and characteristically old bulk radiocarbon (14C) ages (4000 - 6000 years) that exceed the timescales of overturning circulation. Although this refractory dissolved organic carbon (RDOC) is present throughout the oceans as a major reservoir of the global carbon cycle, its sources and sinks are poorly constrained. Recently, RDOC was proposed to be removed from the oceans through adsorption onto the surfaces of rising bubble plumes produced by breaking waves, ejection into the atmosphere via bubble bursting as a component of primary marine aerosol (PMA), and subsequent oxidation in the atmosphere. To test this mechanism, we used natural abundance 14C (5730 ± 40 yr half-life) to trace the fraction of RDOC in PMA produced in a high capacity generator at two biologically-productive and two oligotrophic hydrographic stations in the Northwest Atlantic Ocean during a research cruise aboard the R/V Endeavor (Sep - Oct 2016). The 14C signatures of PMA separately generated day and night from near-surface (5 m) and deep (2500 m) seawater were compared with corresponding 14C signatures in seawater of near-surface dissolved inorganic carbon (DIC, a proxy for recently produced organic matter), bulk deep DOC (a proxy for RDOC), and near-surface bulk DOC. Results constrain the selectivity of PMA formation from RDOC in natural mixtures of recently produced and refractory DOC. The implications of these results for PMA formation and RDOC biogeochemistry will be discussed.

  16. Origin of organic matter in the protosolar nebula and in comets

    NASA Technical Reports Server (NTRS)

    Greenberg, J. M.; Shalabiea, O. M.; Mendoza-Gomez, C. X.; Schutte, W.; Gerakines, P. A.

    1994-01-01

    Comet organics are traced to their origin in interstellar space. Possible sources of comet organics from solar nebula chemistry are briefly discussed. The infrared spectra of interstellar dust are compared with spectra of solar (space) irradiated laboratory organic residues and with meteorites. The spectra compare very favorably. The atomic composition of first generation laboratory organic residues compares favorably with that of comet Halley organics if divided into approrpriate 'volatile' (less refreactory) and 'refractory' (more refractory) complex organics.

  17. Analysis of organic grain coatings in primitive interplanetary dust particles: Implications for the origin of Solar System organic matter

    NASA Astrophysics Data System (ADS)

    Flynn, George

    Analysis of organic grain coatings in primitive interplanetary dust particles: Implications for the origin of Solar System organic matter Chondritic, porous interplanetary dust particles (CP IDPs), the most primitive samples of extraterrestrial material available for laboratory analysis [1], are unequilibrated aggregates of mostly submicron, anhydrous grains of a diverse mineralogy. They contain organic matter not produced by parent body aqueous processing [2], some carrying H and N isotopic anomalies consistent with molecular cloud or outer Solar System material [3]. Scanning Transmission X-Ray Microscope (STXM) imaging at the C K-edge shows the individual grains in 10 micron aggregate CP IDPs are coated by a layer of carbonaceous material 100 nm thick. This structure implies a three-step formation sequence. First, individual grains condensed from the cooling nebular gas. Then complex, refractory organic molecules covered the surfaces of the grains either by deposition, formation in-situ, or a combination of both processes. Finally, the grains collided and stuck together forming the first dust-size material in the Solar System. Ultramicrotome sections, 70 to 100 nm thick were cut from several CP IDPs, embedded in elemental S to avoid exposure to C-based embedding media. X-ray Absorption Near Edge Structure (XANES) spectra were derived from image stacks obtained using a STXM. "Cluster analysis" was used to compare the C-XANES spectra from each of the pixels in an image stack and identify pixels exhibiting similar spectra. When applied to a CP IDP, cluster analysis identifies most carbonaceous grain coatings in a particle as having similar C-XANES spectra. Two processes are commonly suggested in the literature for production of organic grain coatings. The similarity in thickness and C-XANES spectra of the coatings on different minerals in the same IDP indicates the first, mineral specific catalysis, was not the process that produced these organic rims. Our results

  18. Fate and wetting potential of bio-refractory organics in membrane distillation for coke wastewater treatment.

    PubMed

    Ren, Jing; Li, Jianfeng; Chen, Zuliang; Cheng, Fangqin

    2018-06-02

    Membrane distillation (MD) has been hindered in industrial applications due to the potential wetting or fouling caused by complicated organic compositions. This study investigated the correlations between the fate and wetting potential of bio-refractory organics in the MD process, where three coke wastewater samples pre-treated with bio-degradation and coagulation served as feed solutions. Results showed that although most of the bio-refractory organics in coke wastewater were rejected by the hydrophobic membrane, some volatile aromatic organics including benzenes, phenols, quinolines and naphthalenes passed through the membrane during the MD process. Interestingly, membrane wetting occurred coincidently with the penetration of phenolic and heterocyclic organics. The wetting rate was obviously correlated with the feed composition and membrane surface properties. Ultimately, novel insights into the anti-wetting strategy of MD with bio-refractory organics was proposed, illustrating that the polyaluminum chloride/polyacrylamide coagulation not only removed contaminants which could accelerate membrane wetting, but also retarded membrane wetting by the complexation with organics. The deposition of these complexes on the membrane surface introduced a secondary hydrophilic layer on the hydrophobic substrate, which established a composite membrane structure with superior wetting resistance. These new findings would be beneficial to wetting control in membrane distillation for wastewater treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Biochemical Characteristics of Organic Matter in a Guano Concretion of Late Miocene or Pliocene Age from Manchester Parish in Jamaica

    PubMed Central

    Spence, Adrian; Hanson, Richard E.; Johnson, Toni; Robinson, Claion; Annells, Richard N.

    2013-01-01

    The biogeochemical fate of organic matter (OM) entering soils is an important issue that must be examined to better understand its roles in nitrogen cycling and as a natural modulator of soil-atmospheric carbon fluxes. Despite these critical roles, there are uncertainties in estimating the contribution of this feedback mechanism due in part to a lack of molecular-level information regarding the origin and labile and refractory inventories of OM in soils. In this study, we used a multi-analytical approach to determine molecular-level information for the occurrence and stabilization of OM in a bird guano concretion of the Late Miocene or Pliocene age in Jamaica. We determined the specific organic structures persisting in the concretion and the possible contribution of fossil organic matter to the OM pool in modern environments. Our results indicate that aliphatic species, presumably of a highly polymethylenic nature [(CH2)n], may significantly contribute to the stable soil-C pool. Although not as significant, proteins and carbohydrates were also enriched in the sample, further suggesting that fossil organic matter may contribute to carbon and nitrogen pools in present day soil organic matter. PMID:23843688

  20. Biochemical characteristics of organic matter in a guano concretion of late miocene or pliocene age from manchester parish in Jamaica.

    PubMed

    Spence, Adrian; Hanson, Richard E; Johnson, Toni; Robinson, Claion; Annells, Richard N

    2013-01-01

    The biogeochemical fate of organic matter (OM) entering soils is an important issue that must be examined to better understand its roles in nitrogen cycling and as a natural modulator of soil-atmospheric carbon fluxes. Despite these critical roles, there are uncertainties in estimating the contribution of this feedback mechanism due in part to a lack of molecular-level information regarding the origin and labile and refractory inventories of OM in soils. In this study, we used a multi-analytical approach to determine molecular-level information for the occurrence and stabilization of OM in a bird guano concretion of the Late Miocene or Pliocene age in Jamaica. We determined the specific organic structures persisting in the concretion and the possible contribution of fossil organic matter to the OM pool in modern environments. Our results indicate that aliphatic species, presumably of a highly polymethylenic nature [(CH2)n], may significantly contribute to the stable soil-C pool. Although not as significant, proteins and carbohydrates were also enriched in the sample, further suggesting that fossil organic matter may contribute to carbon and nitrogen pools in present day soil organic matter.

  1. Electrocoagulation of bio-filtrated landfill leachate: Fractionation of organic matter and influence of anode materials.

    PubMed

    Dia, Oumar; Drogui, Patrick; Buelna, Gerardo; Dubé, Rino; Ihsen, Ben Salah

    2017-02-01

    Electrocoagulation (EC) was employed to treat residual organic matter from a landfill leachate pretreated by an aerated bio-filter system. Organic matter (humic acids (HA), fulvic acids (FA) and hydrophilic compounds (Hyl)) was fractionated using DAX-8 resin in order to estimate the efficiency of EC on each fraction. Initial characterization of the bio-filtrated landfill leachate showed that humic substances (HA + FA) represented nearly 90% of TOC. The effects of current densities, type of anode (Aluminum versus iron), and treatment time on the performance of COD removal were investigated. The best COD removal performances were recorded at a current density ranging between 8.0 and 10 mA cm -2 during 20 min of treatment time. Under these conditions, 70% and 65% of COD were removed using aluminum and iron electrodes, respectively. The fractionating of organic matter after EC treatment revealed that HA was completely removed using either aluminum or iron anode. However, FA and Hyl fractions were partially removed, with the percentages varying from 57 to 60% and 37-46%, respectively. FA and Hyl removal were quite similar using either aluminum or iron anode. Likewise, a significant decrease in 254-nm absorbance was recorded (UV 254 removal of 79-80%) using either type of anode. These results proved that EC is a suitable and efficient approach for treating the residual refractory organic matter from a landfill leachate previously treated by a biological system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Dissolved effluent organic matter: Characteristics and potential implications in wastewater treatment and reuse applications.

    PubMed

    Michael-Kordatou, I; Michael, C; Duan, X; He, X; Dionysiou, D D; Mills, M A; Fatta-Kassinos, D

    2015-06-15

    Wastewater reuse is currently considered globally as the most critical element of sustainable water management. The dissolved effluent organic matter (dEfOM) present in biologically treated urban wastewater, consists of a heterogeneous mixture of refractory organic compounds with diverse structures and varying origin, including dissolved natural organic matter, soluble microbial products, endocrine disrupting compounds, pharmaceuticals and personal care products residues, disinfection by-products, metabolites/transformation products and others, which can reach the aquatic environment through discharge and reuse applications. dEfOM constitutes the major fraction of the effluent organic matter (EfOM) and due to its chemical complexity, it is necessary to utilize a battery of complementary techniques to adequately describe its structural and functional character. dEfOM has been shown to exhibit contrasting effects towards various aquatic organisms. It decreases metal uptake, thus potentially reducing their bioavailability to exposed organisms. On the other hand, dEfOM can be adsorbed on cell membranes inducing toxic effects. This review paper evaluates the performance of various advanced treatment processes (i.e., membrane filtration and separation processes, activated carbon adsorption, ion-exchange resin process, and advanced chemical oxidation processes) in removing dEfOM from wastewater effluents. In general, the literature findings reveal that dEfOM removal by advanced treatment processes depends on the type and the amount of organic compounds present in the aqueous matrix, as well as the operational parameters and the removal mechanisms taking place during the application of each treatment technology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Refractory Access Disorders and the Organization of Concrete and Abstract Semantics: Do they Differ?

    PubMed Central

    Hamilton, A. Cris; Coslett, H. Branch

    2010-01-01

    Patients with “refractory semantic access deficits” demonstrate several unique features that make them important sources of insight into the organization of semantic representations. Here we attempt to replicate several novel findings from single-case studies reported in the literature. Patient UM– 103 displays the cardinal features of a “refractory semantic access deficit” and showed many of the same effects of semantic relatedness reported in the literature. However, when probing concrete and abstract words, this patient revealed very different patterns of performance compared to two previously reported patients. We discuss the implications of our data for models of semantic organization of abstract and concrete words. PMID:18569737

  4. What is soil organic matter worth?

    PubMed

    Sparling, G P; Wheeler, D; Vesely, E-T; Schipper, L A

    2006-01-01

    The conservation and restoration of soil organic matter are often advocated because of the generally beneficial effects on soil attributes for plant growth and crop production. More recently, organic matter has become important as a terrestrial sink and store for C and N. We have attempted to derive a monetary value of soil organic matter for crop production and storage functions in three contrasting New Zealand soil orders (Gley, Melanic, and Granular Soils). Soil chemical and physical characteristics of real-life examples of three pairs of matched soils with low organic matter contents (after long-term continuous cropping for vegetables or maize) or high organic matter content (continuous pasture) were used as input data for a pasture (grass-clover) production model. The differences in pasture dry matter yields (non-irrigated) were calculated for three climate scenarios (wet, dry, and average years) and the yields converted to an equivalent weight and financial value of milk solids. We also estimated the hypothetical value of the C and N sequestered during the recovery phase of the low organic matter content soils assuming trading with C and N credits. For all three soil orders, and for the three climate scenarios, pasture dry matter yields were decreased in the soils with lower organic matter contents. The extra organic matter in the high C soils was estimated to be worth NZ$27 to NZ$150 ha(-1) yr(-1) in terms of increased milk solids production. The decreased yields from the previously cropped soils were predicted to persist for 36 to 125 yr, but with declining effect as organic matter gradually recovered, giving an accumulated loss in pastoral production worth around NZ$518 to NZ$1239 ha(-1). This was 42 to 73 times lower than the hypothetical value of the organic matter as a sequestering agent for C and N, which varied between NZ$22,963 to NZ$90,849 depending on the soil, region, discount rates, and values used for carbon and nitrogen credits.

  5. SAR202 Genomes from the Dark Ocean Predict Pathways for the Oxidation of Recalcitrant Dissolved Organic Matter

    PubMed Central

    Landry, Zachary; Swan, Brandon K.; Herndl, Gerhard J.; Stepanauskas, Ramunas

    2017-01-01

    ABSTRACT Deep-ocean regions beyond the reach of sunlight contain an estimated 615 Pg of dissolved organic matter (DOM), much of which persists for thousands of years. It is thought that bacteria oxidize DOM until it is too dilute or refractory to support microbial activity. We analyzed five single-amplified genomes (SAGs) from the abundant SAR202 clade of dark-ocean bacterioplankton and found they encode multiple families of paralogous enzymes involved in carbon catabolism, including several families of oxidative enzymes that we hypothesize participate in the degradation of cyclic alkanes. The five partial genomes encoded 152 flavin mononucleotide/F420-dependent monooxygenases (FMNOs), many of which are predicted to be type II Baeyer-Villiger monooxygenases (BVMOs) that catalyze oxygen insertion into semilabile alicyclic alkanes. The large number of oxidative enzymes, as well as other families of enzymes that appear to play complementary roles in catabolic pathways, suggests that SAR202 might catalyze final steps in the biological oxidation of relatively recalcitrant organic compounds to refractory compounds that persist. PMID:28420738

  6. Morphometric brain characterization of refractory obsessive-compulsive disorder: diffeomorphic anatomic registration using exponentiated Lie algebra.

    PubMed

    Tang, Wanjie; Li, Bin; Huang, Xiaoqi; Jiang, Xiaoyu; Li, Fei; Wang, Lijuan; Chen, Taolin; Wang, Jinhui; Gong, Qiyong; Yang, Yanchun

    2013-10-01

    Few studies have used neuroimaging to characterize treatment-refractory obsessive-compulsive disorder (OCD). This study sought to explore gray matter structure in patients with treatment-refractory OCD and compare it with that of healthy controls. A total of 18 subjects with treatment-refractory OCD and 26 healthy volunteers were analyzed by MRI using a 3.0-T scanner and voxel-based morphometry (VBM). Diffeomorphic anatomical registration using exponentiated Lie algebra (DARTEL) was used to identify structural changes in gray matter associated with treatment-refractory OCD. A partial correlation model was used to analyze whether morphometric changes were associated with Yale-Brown Obsessive-Compulsive Scale scores and illness duration. Gray matter volume did not differ significantly between the two groups. Treatment-refractory OCD patients showed significantly lower gray matter density than healthy subjects in the left posterior cingulate cortex (PCC) and mediodorsal thalamus (MD) and significantly higher gray matter density in the left dorsal striatum (putamen). These changes did not correlate with symptom severity or illness duration. Our findings provide new evidence of deficits in gray matter density in treatment-refractory OCD patients. These patients may show characteristic density abnormalities in the left PCC, MD and dorsal striatum (putamen), which should be verified in longitudinal studies. © 2013. Published by Elsevier Inc. All rights reserved.

  7. Linking groundwater dissolved organic matter to sedimentary organic matter from a fluvio-lacustrine aquifer at Jianghan Plain, China by EEM-PARAFAC and hydrochemical analyses.

    PubMed

    Huang, Shuang-bing; Wang, Yan-xin; Ma, Teng; Tong, Lei; Wang, Yan-yan; Liu, Chang-rong; Zhao, Long

    2015-10-01

    The sources of dissolved organic matter (DOM) in groundwater are important to groundwater chemistry and quality. This study examined similarities in the nature of DOM and investigated the link between groundwater DOM (GDOM) and sedimentary organic matter (SOM) from a lacustrine-alluvial aquifer at Jianghan Plain. Sediment, groundwater and surface water samples were employed for SOM extraction, optical and/or chemical characterization, and subsequent fluorescence excitation-emission matrix (EEM) and parallel factor analyses (PARAFAC). Spectroscopic properties of bulk DOM pools showed that indices indicative of GDOM (e.g., biological source properties, humification level, aromaticity and molecule mobility) varied within the ranges of those of two extracted end-members of SOM: humic-like materials and microbe-associated materials. The coexistence of PARAFAC compositions and the sustaining internal relationship between GDOM and extracted SOM indicate a similar source. The results from principal component analyses with selected spectroscopic indices showed that GDOM exhibited a transition trend regarding its nature: from refractory high-humification DOM to intermediate humification DOM and then to microbe-associated DOM, with decreasing molecular weight. Correlations of spectroscopic indices with physicochemical parameters of the groundwater suggested that GDOM was released from SOM and was modified by microbial diagenetic processes. The current study demonstrated the associations of GDOM with SOM from a spectroscopic viewpoint and provided new evidence supporting SOM as the source of GDOM. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Organic matter in central California radiation fogs.

    PubMed

    Herckes, Pierre; Lee, Taehyoung; Trenary, Laurie; Kang, Gongunn; Chang, Hui; Collett, Jeffrey L

    2002-11-15

    Organic matter was studied in radiation fogs in the San Joaquin Valley of California during the California Regional Particulate Air Quality Study (CRPAQS). Total organic carbon (TOC) concentrations ranged from 2 to 40 ppm of C. While most organic carbon was found in solution as dissolved organic carbon (DOC), 23% on average was not dissolved inside the fog drops. We observe a clear variation of organic matter concentration with droplet size. TOC concentrations in small fog drops (<17 microm) were a factor of 3, on average, higher than TOC concentrations in larger drops. As much as half of the dissolved organic matter was determined to have a molecular weight higher than 500 Da. Deposition fluxes of organic matter in fog drops were high (0.5-4.3 microg of C m(-2) min(-1)), indicating the importance of fog processing as a vector for removal of organic matter from the atmosphere. Deposition velocities of organic matter, however, were usually found to be lower than deposition velocities for fogwater, consistent with the enrichment of the organic matter in smaller fog drops with lower terminal settling velocities.

  9. SAR202 Genomes from the Dark Ocean Predict Pathways for the Oxidation of Recalcitrant Dissolved Organic Matter.

    PubMed

    Landry, Zachary; Swan, Brandon K; Herndl, Gerhard J; Stepanauskas, Ramunas; Giovannoni, Stephen J

    2017-04-18

    Deep-ocean regions beyond the reach of sunlight contain an estimated 615 Pg of dissolved organic matter (DOM), much of which persists for thousands of years. It is thought that bacteria oxidize DOM until it is too dilute or refractory to support microbial activity. We analyzed five single-amplified genomes (SAGs) from the abundant SAR202 clade of dark-ocean bacterioplankton and found they encode multiple families of paralogous enzymes involved in carbon catabolism, including several families of oxidative enzymes that we hypothesize participate in the degradation of cyclic alkanes. The five partial genomes encoded 152 flavin mononucleotide/F420-dependent monooxygenases (FMNOs), many of which are predicted to be type II Baeyer-Villiger monooxygenases (BVMOs) that catalyze oxygen insertion into semilabile alicyclic alkanes. The large number of oxidative enzymes, as well as other families of enzymes that appear to play complementary roles in catabolic pathways, suggests that SAR202 might catalyze final steps in the biological oxidation of relatively recalcitrant organic compounds to refractory compounds that persist. IMPORTANCE Carbon in the ocean is massively sequestered in a complex mixture of biologically refractory molecules that accumulate as the chemical end member of biological oxidation and diagenetic change. However, few details are known about the biochemical machinery of carbon sequestration in the deep ocean. Reconstruction of the metabolism of a deep-ocean microbial clade, SAR202, led to postulation of new biochemical pathways that may be the penultimate stages of DOM oxidation to refractory forms that persist. These pathways are tied to a proliferation of oxidative enzymes. This research illuminates dark-ocean biochemistry that is broadly consequential for reconstructing the global carbon cycle. Copyright © 2017 Landry et al.

  10. Black Carbon in Estuarine (Coastal) High-molecular-weight Dissolved Organic Matter

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Dissolved organic matter (DOM) in the ocean constitutes one of the largest pools of organic carbon in the biosphere, yet much of its composition is uncharacterized. Observations of black carbon (BC) particles (by-products of fossil fuel combustion and biomass burning) in the atmosphere, ice, rivers, soils and marine sediments suggest that this material is ubiquitous, yet the contribution of BC to the ocean s DOM pool remains unknown. Analysis of high-molecular-weight DOM isolated from surface waters of two estuaries in the northwest Atlantic Ocean finds that BC is a significant component of DOM, suggesting that river-estuary systems are important exporters of BC to the ocean through DOM. We show that BC comprises 4-7% of the dissolved organic carbon (DOC) at coastal ocean sites, which supports the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition. Flux calculations suggest that BC could be as important as vascular plant-derived lignin in terms of carbon inputs to the ocean. Production of BC sequesters fossil fuel- and biomass-derived carbon into a refractory carbon pool. Hence, BC may represent a significant sink for carbon to the ocean.

  11. Soft X-Ray Photoionizing Organic Matter from Comet Wild 2: Evidence for the Production of Organic Matter by Impact Processes

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael E.; Wirick, S.; Flynn, G. J.; Jacobsen, C.; Na

    2011-01-01

    The Stardust mission collected both mineral and organic matter from Comet Wild 2 [1,2,3,4]. The organic matter discovered in Comet Wild 2 ranges from aromatic hydrocarbons to simple aliphatic chains and is as diverse and complex as organic matter found in carbonaceous chondrites and interplanetary dust particles.[3,5,6,7,8,9]. Compared to insoluble organic matter from carbonaceous chondrites the organic matter in Comet Wild 2 more closely resembles organic matter found in the IDPS both hydrous and anhydrous. Common processes for the formation of organic matter in space include: Fischer-Tropsch, included with this aqueous large body and moderate heating alterations; UV irradiation of ices; and; plasma formation and collisions. The Fischer-Tropsch could only occur on large bodies processes, and the production of organic matter by UV radiation is limited by the penetration depth of UV photons, on the order of a few microns or less for most organic matter, so once organic matter coats the ices it is formed from, the organic production process would stop. Also, the organic matter formed by UV irradiation would, by the nature of the process, be in-sensitive to photodissocation from UV light. The energy of soft X-rays, 280-300 eV occur within the range of extreme ultraviolet photons. During the preliminary examination period we found a particle that nearly completely photoionized when exposed to photons in the energy range 280-310eV. This particle experienced a long exposure time to the soft x-ray beam which caused almost complete mass loss so little chemical information was obtain. During the analysis of our second allocation we have discovered another particle that photoionized at these energies but the exposure time was limited and more chemical information was obtained.

  12. Cometary dust: the diversity of primitive refractory grains

    PubMed Central

    Ishii, H. A.

    2017-01-01

    Comet dust is primitive and shows significant diversity. Our knowledge of the properties of primitive cometary particles has expanded significantly through microscale investigations of cosmic dust samples (anhydrous interplanetary dust particles (IDPs), chondritic porous (CP) IDPs and UltraCarbonaceous Antarctic micrometeorites, Stardust and Rosetta), as well as through remote sensing (Spitzer IR spectroscopy). Comet dust are aggregate particles of materials unequilibrated at submicrometre scales. We discuss the properties and processes experienced by primitive matter in comets. Primitive particles exhibit a diverse range of: structure and typology; distribution of constituents; concentration and form of carbonaceous and refractory organic matter; Mg- and Fe-contents of the silicate minerals; sulfides; existence/abundance of type II chondrule fragments; high-temperature calcium–aluminium inclusions and ameboid-olivine aggregates; and rarely occurring Mg-carbonates and magnetite, whose explanation requires aqueous alteration on parent bodies. The properties of refractory materials imply there were disc processes that resulted in different comets having particular selections of primitive materials. The diversity of primitive particles has implications for the diversity of materials in the protoplanetary disc present at the time and in the region where the comets formed. This article is part of the themed issue ‘Cometary science after Rosetta’. PMID:28554979

  13. Reduction in the exchange of coastal dissolved organic matter and microgels by inputs of extra riverine organic matter.

    PubMed

    Shiu, Ruei-Feng; Lee, Chon-Lin; Chin, Wei-Chun

    2017-12-15

    Rivers drive large amounts of terrestrial and riverine organic matter into oceans. These organic materials may alter the self-assembly of marine dissolved organic matter (DOM) polymers into microgels and can even affect the behavior of existing natural microgels. We used Suwannee River humic acid, fulvic acid, and natural organic matter as a model of riverine organic matter (ROM) to investigate the impacts of ROM input on DOM polymer and microgel conversion. Our results indicated that the release of extra ROM, even at low concentrations (0.1-10 mg L -1 ), into the marine organic matter pool decreased the size of self-assembled DOM polymers (from 4-5 μm to < 1 μm) and dispersed the existing natural microgels into smaller particles (from 4-5 μm to 2-3 μm). The particle size of the microgel phase was also less sensitive than that of the DOM polymers to external changes (addition of ROM). This size reduction in DOM aggregation and existing microgels may be closely tied to the surface chemistry of the organic matter, such as negative surface charge stabilization and Ca 2+ cross-linking bridges. These findings reveal that ROM inputs may therefore impede the self-assembly of DOM polymers into particulate organic matter and reduce the sedimentation flux of organic carbon and other elements from surface water to the deep ocean, thereby disturbing the biological pump, the downward transportation of nutrients, and the marine organic carbon cycle. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. The contentious nature of soil organic matter.

    PubMed

    Lehmann, Johannes; Kleber, Markus

    2015-12-03

    The exchange of nutrients, energy and carbon between soil organic matter, the soil environment, aquatic systems and the atmosphere is important for agricultural productivity, water quality and climate. Long-standing theory suggests that soil organic matter is composed of inherently stable and chemically unique compounds. Here we argue that the available evidence does not support the formation of large-molecular-size and persistent 'humic substances' in soils. Instead, soil organic matter is a continuum of progressively decomposing organic compounds. We discuss implications of this view of the nature of soil organic matter for aquatic health, soil carbon-climate interactions and land management.

  15. Interstellar organic matter in meteorites

    NASA Technical Reports Server (NTRS)

    Yang, J.; Epstein, S.

    1983-01-01

    Deuterium-enriched hydrogen is present in organic matter in such meteorites as noncarbonaceous chondrites. The majority of the unequilibrated primitive meteorites contain hydrogen whose D/H ratios are greater than 0.0003, requiring enrichment (relative to cosmic hydrogen) by isotope exchange reactions taking place below 150 K. The D/H values presented are the lower limits for the organic compounds derived from interstellar molecules, since all processes subsequent to their formation, including terrestrial contamination, decrease their D/H ratios. In contrast, the D/H ratios of hydrogen associated with hydrated silicates are relatively uniform for the meteorites analyzed. The C-13/C-12 ratios of organic matter, irrespective of D/H ratio, lie well within those observed for the earth. Present findings suggest that other interstellar material, in addition to organic matter, is preserved and is present in high D/H ratio meteorites.

  16. Contributions of organic and inorganic matter to sediment ...

    EPA Pesticide Factsheets

    A mixing model derived from first principles describes the bulk density (BD) of intertidal wetland sediments as a function of loss on ignition (LOI). The model assumes the bulk volume of sediment equates to the sum of self-packing volumes of organic and mineral components or BD = 1/[LOI/k1 + (1-LOI)/k2], where k1 and k2 are the self-packing densities of the pure organic and inorganic components, respectively. The model explained 78% of the variability in total BD when fitted to 5075 measurements drawn from 33 wetlands distributed around the conterminous United States. The values of k1 and k2 were estimated to be 0.085 ± 0.0007 g cm-3 and 1.99 ± 0.028 g cm-3, respectively. Based on the fitted organic density (k1) and constrained by primary production, the model suggests that the maximum steady state accretion arising from the sequestration of refractory organic matter is ≤ 0.3 cm yr-1. Thus, tidal peatlands are unlikely to survive indefinitely a higher rate of sea-level rise in the absence of a significant source of mineral sediment. Application of k2 to a mineral sediment load typical of East and eastern Gulf Coast estuaries gives a vertical accretion rate from inorganic sediment of 0.2 cm yr-1. Total steady state accretion is the sum of the parts and therefore should not be greater than 0.5 cm yr-1 under the assumptions of the model. Accretion rates could deviate from this value depending on variation in plant productivity, root:shoot ratio, suspended sedim

  17. Impact of natural (storm) and anthropogenic (trawling) sediment resuspension on particulate organic matter in coastal environments

    NASA Astrophysics Data System (ADS)

    Pusceddu, A.; Grémare, A.; Escoubeyrou, K.; Amouroux, J. M.; Fiordelmondo, C.; Danovaro, R.

    2005-12-01

    In order to assess the impact of natural and anthropogenic sediment resuspension on quantity, biochemical composition and bioavailability of particulate organic matter (POM), two field investigations were carried out in two shallow coastal areas of the Mediterranean Sea. In the Gulf of Lions, we investigated the impact of a storm resuspension of sediment, whereas in the Thermaikos Gulf we investigated the impact of bottom trawling. Resuspension in the Gulf of Lions determined the increase of sedimentation rates, modified the composition of the organic fraction of settling particles and decreased the labile fraction of POM, as indicated by a drop in the enzymatically hydrolysable amino acid fraction. The increase in the refractory fraction, following short-term storm-induced resuspension, increased also the contribution of glycine and decreased the contribution of aspartic acid contents to the total amino acid pools. Trawling activities in Thermaikos Gulf determined a significant increase in suspended POM concentrations and important changes in its biochemical composition. After trawling, the protein to carbohydrate ratio decreased (as a result of a major input of sedimentary carbohydrates at the water-sediment interface) and the fraction of enzymatically hydrolysable biopolymeric C decreased by ≈30%, thus reducing the bioavailability of resuspended organic particles. Results of the present study indicate that changes in suspended POM, induced by storms and trawling activities, can have similar consequences on benthic systems and on food webs. In fact, the potential benefit of increased organic particle concentration for suspension feeders, is depressed by the shift of suspended food particles towards a more refractory composition.

  18. Subcritical water extraction of organic matter from sedimentary rocks.

    PubMed

    Luong, Duy; Sephton, Mark A; Watson, Jonathan S

    2015-06-16

    Subcritical water extraction of organic matter containing sedimentary rocks at 300°C and 1500 psi produces extracts comparable to conventional solvent extraction. Subcritical water extraction of previously solvent extracted samples confirms that high molecular weight organic matter (kerogen) degradation is not occurring and that only low molecular weight organic matter (free compounds) are being accessed in analogy to solvent extraction procedures. The sedimentary rocks chosen for extraction span the classic geochemical organic matter types. A type I organic matter-containing sedimentary rock produces n-alkanes and isoprenoidal hydrocarbons at 300°C and 1500 psi that indicate an algal source for the organic matter. Extraction of a rock containing type II organic matter at the same temperature and pressure produces aliphatic hydrocarbons but also aromatic compounds reflecting the increased contributions from terrestrial organic matter in this sample. A type III organic matter-containing sample produces a range of non-polar and polar compounds including polycyclic aromatic hydrocarbons and oxygenated aromatic compounds at 300°C and 1500 psi reflecting a dominantly terrestrial origin for the organic materials. Although extraction at 300°C and 1500 psi produces extracts that are comparable to solvent extraction, lower temperature steps display differences related to organic solubility. The type I organic matter produces no products below 300°C and 1500 psi, reflecting its dominantly aliphatic character, while type II and type III organic matter contribute some polar components to the lower temperature steps, reflecting the chemical heterogeneity of their organic inventory. The separation of polar and non-polar organic compounds by using different temperatures provides the potential for selective extraction that may obviate the need for subsequent preparative chromatography steps. Our results indicate that subcritical water extraction can act as a suitable

  19. Warming-Induced Changes to the Molecular Composition of Soil Organic Matter

    NASA Astrophysics Data System (ADS)

    Feng, X.; Simpson, M. J.; Simpson, A. J.; Wilson, K. P.; Williams, D.

    2007-12-01

    Soil organic matter (SOM) contains two times more carbon than the atmosphere and the potential changes to SOM quantity and quality with global warming are a major concern. It is commonly believed that global warming will accelerate the decomposition of labile SOM compounds while refractory SOM constituents will remain stable. However, experimental evidence of molecular-level changes to SOM composition with global warming is currently lacking. Here we employ SOM biomarkers and nuclear magnetic resonance (NMR) spectroscopy to study SOM composition and degradation in a soil warming experiment in southern Ontario, Canada. The soil warming experiment consisted of a control and a treatment plot in a mixed forest that had a temperature difference of about 5 degrees C for 14 months. Before soil warming the control and treatment plots had the same organic carbon (OC) content and SOM composition. Soil warming significantly increased soil OC content and the abundance of cutin-derived carbon originating from leaf tissues and decreased carbohydrates that are regarded as easily degradable. Lignin components, which are believed to be part of the stable and slowly-cycling SOM, were observed to be in an advanced stage of degradation. This observation is corroborated by increases in fungal biomass in the warmed soil because fungi are considered the primary decomposer of lignin in the soil environment. An NMR study of SOM in the warmed and control plots indicates that alkyl carbon, mainly originating from plant cuticles in the soil, increased in the warmed soil while O-alkyl carbon, primarily occurring in carbohydrates, decreased. Aromatic and phenolic carbon regions, which include the main structures found in lignin, decreased in the warmed soil. These data collectively suggest that there is a great potential for lignin degradation with soil warming, and that the refractory (aromatic) soil carbon storage may be reduced as a result of increased fungal growth in a warmer climate.

  20. How important are intertidal ecosystems for global biogeochemical cycles? Molecular and isotopic evidence for major outwelling of photo-bleached dissolved organic matter from mangroves.

    NASA Astrophysics Data System (ADS)

    Dittmar, T.; Cooper, W. T.; Koch, B. P.; Kattner, G.

    2006-05-01

    Organic matter, which is dissolved in low concentrations in the vast waters of the oceans, contains a total amount of carbon similar to atmospheric carbon dioxide. To understand global biogeochemical cycles it is crucial to quantify the sources of marine dissolved organic carbon (DOC). We investigated the impact of mangroves, the dominant intertidal vegetation of the tropics, on marine DOC inventories. Stable carbon- isotopes, ultrahigh-resolution mass spectrometry (FTICRMS), lignin-derived phenols and proton nuclear magnetic resonance spectroscopy showed that mangroves are the main source of terrigenous DOC on the shelf off Northern Brazil. Sunlight efficiently destroyed aromatic molecules during transport offshore, removing about one third of mangrove-derived DOC. The remainder was refractory and may thus be distributed over the oceans. On a global scale, we estimate that mangroves account for more than 10 percent of the terrestrially- derived, refractory DOC transported to the ocean, while they cover less than 0.1 percent of the continents' surface.

  1. Organic matters: investigating the sources, transport, and fate of organic matter in Fanno Creek, Oregon

    USGS Publications Warehouse

    Sobieszczyk, Steven; Keith, Mackenzie K.; Goldman, Jami H.; Rounds, Stewart A.

    2015-01-01

    The U.S. Geological Survey (USGS), in cooperation with Clean Water Services, recently completed an investigation into the sources, transport, and fate of organic matter in the Fanno Creek watershed. The information provided by this investigation will help resource managers to implement strategies aimed at decreasing the excess supply of organic matter that contributes to low dissolved-oxygen levels in Fanno Creek and downstream in the Tualatin River during summer. This fact sheet summarizes the findings of the investigation.

  2. Alteration of organic matter during infaunal polychaete gut passage and links to sediment organic geochemistry. Part I: Amino acids

    NASA Astrophysics Data System (ADS)

    Woulds, Clare; Middelburg, Jack J.; Cowie, Greg L.

    2012-01-01

    labelled glycine. Possible mechanisms for this enrichment include accumulation through inclusion in tissues with long residence times, preferential preservation (i.e. selection against) during metabolism, production from other labelled amino acids during varied metabolic processes, and accumulation in refractory by-products of secondary bacterial production. Overall, similarities were observed between amino-acid decay patterns in faunated microcosms, afaunal controls, and those previously reported in marine sediments. Thus, while polychaete gut passage did produce compound-selective accumulation and losses of certain amino acids in polychaete tissues and faecal matter, the impact of polychaete gut passage on sediment organic geochemistry was difficult to deconvolve from microbial decay. Despite processing large volumes of organic matter, polychaetes may not have distinctive influence on sediment compositions, possibly because metabolic processes concerning amino acids may be broadly similar across a wide range of organisms.

  3. Organic and inorganic speciation of particulate matter formed during different combustion phases in an improved cookstove.

    PubMed

    Leavey, Anna; Patel, Sameer; Martinez, Raul; Mitroo, Dhruv; Fortenberry, Claire; Walker, Michael; Williams, Brent; Biswas, Pratim

    2017-10-01

    Residential solid fuel combustion in cookstoves has established health impacts including bladder and lung cancers, cataracts, low birth weight, and pneumonia. The chemical composition of particulate matter (PM) from 4 commonly-used solid fuels (coal, dung, ambient/dry applewood, and oakwood pellets), emitted from a gasifier cookstove, as well as propane, were examined. Temporal changes between the different cookstove burn-phases were also explored. Normalized concentrations of non-refractory PM 1 , total organics, chloride, ammonium, nitrate, sulfate, and 41 particle-phase polycyclic aromatic hydrocarbons (PAHs) were measured using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a Thermal desorption Aerosol Gas chromatograph (TAG), respectively. Coal demonstrated the highest fraction of organic matter in its particulate emission composition (98%), followed by dung (94%). Coal and dung also demonstrated the highest numbers and concentrations of PAHs. While dry applewood emitted ten times lower organic matter compared to ambient applewood, a higher fraction of these organics was composed of PAHs, especially the more toxic ones such as benzo(a)pyrene (9.63ng/L versus 0.04ng/L), and benzo(b)fluoranthene (31.32ng/L versus 0.19ng/L). Data from the AMS demonstrated no clear trends for any of the combustion fuels over the different combustion phases unlike the previously reported trends observed for the physical characteristics. Of the solid fuels, pellets demonstrated the lowest emissions. Emissions from propane were below the quantification limit of the instruments. This work highlights the benefits of incorporating additional metrics into the cookstove evaluation process, thus enriching the existing PM data inventory. Copyright © 2017. Published by Elsevier Inc.

  4. The effects of organic matter-mineral interactions and organic matter chemistry on diuron sorption across a diverse range of soils.

    PubMed

    Smernik, Ronald J; Kookana, Rai S

    2015-01-01

    Sorption of non-ionic organic compounds to soil is usually expressed as the carbon-normalized partition coefficient (KOC), because it is assumed that the main factor that influences the amount sorbed is the organic carbon content of the soil. However, KOC can vary by a factor of at least ten across a range of soils. We investigated two potential causes of variation in diuron KOC - organic matter-mineral interactions and organic matter chemistry - for a diverse set of 34 soils from Sri Lanka, representing a wide range of soil types. Treatment with hydrofluoric acid (HF-treatment) was used to concentrate soil organic matter. HF-treatment increased KOC for the majority of soils (average factor 2.4). We attribute this increase to the blocking of organic matter sorption sites in the whole soils by minerals. There was no significant correlation between KOC for the whole soils and KOC for the HF-treated soils, indicating that the importance of organic matter-mineral interactions varied greatly amongst these soils. There was as much variation in KOC across the HF-treated soils as there was across the whole soils, indicating that the nature of soil organic matter is also an important contributor to KOC variability. Organic matter chemistry, determined by solid-state (13)C nuclear magnetic resonance (NMR) spectroscopy, was correlated with KOC for the HF-treated soils. In particular, KOC increased with the aromatic C content (R=0.64, p=1×10(-6)), and decreased with O-alkyl C (R=-0.32, p=0.03) and alkyl C (R=-0.41, p=0.004) content. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Removal of refractory organics in nanofiltration concentrates of municipal solid waste leachate treatment plants by combined Fenton oxidative-coagulation with photo--Fenton processes.

    PubMed

    Li, Jiuyi; Zhao, Lei; Qin, Lele; Tian, Xiujun; Wang, Aimin; Zhou, Yanmei; Meng, Liao; Chen, Yong

    2016-03-01

    Removal of the refractory organic matters in leachate brines generated from nanofiltration unit in two full-scale municipal solid waste landfill leachate treatment plants was investigated by Fenton oxidative-coagulation and ultraviolet photo - Fenton processes in this study. Fenton oxidative-coagulation was performed under the condition of an initial pH of 5.0 and low H2O2/Fe(2+) ratios. After precipitate separation, the remaining organic constituents were further oxidized by photo - Fenton process. For both leachate brines with varying pollution strength, more than 90% COD and TOC reductions were achieved at H2O2/Fe(2+) dosages of 35 mM/8 mM and 90 mM/10 mM, respectively. The effluent COD ranged 120-160 mg/L under the optimal operating conditions, and the biodegradability was increased significantly. Fenton oxidative-coagulation was demonstrated to contribute nearly 70% overall removal of organic matters. In the combined processes, the efficiency of hydrogen peroxide varied from 216 to 228%, which may significantly reduce the operating cost of conventional Fenton method. Six phthalic acid esters and thirteen polycyclic aromatic hydrocarbons were found in leachate brines, and, on the average, around 80% phthalic acid esters and 90% polycyclic aromatic hydrocarbons were removed by the combined treatments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Molybdenum isotope fractionation during adsorption to organic matter

    USGS Publications Warehouse

    King, Elizabeth K.; Perakis, Steven; Pett-Ridge, Julie C.

    2018-01-01

    Organic matter is of emerging interest as a control on molybdenum (Mo) biogeochemistry, and information on isotope fractionation during adsorption to organic matter can improve interpretations of Mo isotope variations in natural settings. Molybdenum isotope fractionation was investigated during adsorption onto insolubilized humic acid (IHA), a surrogate for organic matter, as a function of time (2–170 h) and pH (2–7). For the time series experiment performed at pH 4.2, the average Mo isotope fractionation between the solution and the IHA (Δ98Mosolution-IHA) was 1.39‰ (± 0.16‰, 2σ, based on 98Mo/95Mo relative to the NIST 3134 standard) at steady state. For the pH series experiment, Mo adsorption decreased as pH increased from 2.0 to 6.9, and the Δ98Mosolution-IHA increased from 0.82‰ to 1.79‰. We also evaluated natural Mo isotope patterns in precipitation, foliage, organic horizon, surface mineral soil, and bedrock from 12 forested sites in the Oregon Coast Range. The average Mo isotope offset observed between precipitation and organic (O) horizon soil was 2.1‰, with light Mo isotopes adsorbing preferentially to organic matter. Fractionation during adsorption to organic matter is similar in magnitude and direction to prior observations of Mo fractionation during adsorption to Fe- and Mn- (oxyhydr)oxides. Our finding that organic matter influences Mo isotope composition has important implications for the role of organic matter as a driver of trace metal retention and isotopic fractionation.

  7. Molybdenum isotope fractionation during adsorption to organic matter

    NASA Astrophysics Data System (ADS)

    King, E. K.; Perakis, S. S.; Pett-Ridge, J. C.

    2018-02-01

    Organic matter is of emerging interest as a control on molybdenum (Mo) biogeochemistry, and information on isotope fractionation during adsorption to organic matter can improve interpretations of Mo isotope variations in natural settings. Molybdenum isotope fractionation was investigated during adsorption onto insolubilized humic acid (IHA), a surrogate for organic matter, as a function of time (2-170 h) and pH (2-7). For the time series experiment performed at pH 4.2, the average Mo isotope fractionation between the solution and the IHA (Δ98Mosolution-IHA) was 1.39‰ (±0.16‰, 2σ, based on 98Mo/95Mo relative to the NIST 3134 standard) at steady state. For the pH series experiment, Mo adsorption decreased as pH increased from 2.0 to 6.9, and the Δ98Mosolution-IHA increased from 0.82‰ to 1.79‰. We also evaluated natural Mo isotope patterns in precipitation, foliage, organic horizon, surface mineral soil, and bedrock from 12 forested sites in the Oregon Coast Range. The average Mo isotope offset observed between precipitation and organic (O) horizon soil was 2.1‰, with light Mo isotopes adsorbing preferentially to organic matter. Fractionation during adsorption to organic matter is similar in magnitude and direction to prior observations of Mo fractionation during adsorption to Fe- and Mn- (oxyhydr)oxides. Our finding that organic matter influences Mo isotope composition has important implications for the role of organic matter as a driver of trace metal retention and isotopic fractionation.

  8. An original data treatment for infrared spectra of organic matter, application to extracted soil organic matter

    NASA Astrophysics Data System (ADS)

    Gomes Rossin, Bruna; Redon, Roland; Raynaud, Michel; Nascimento, Nadia Regina; Mounier, Stéphane

    2017-04-01

    Infrared spectra of extracted organic matter are easy and rapid to do, but generally hard to interpreted over the presence or not of certain organic functions. Indeed, the organic matter is a complex mixture of molecules often having absorption overlapping and it is also difficult to have a well calibrated or normalised spectra due to the difficulty to have a well known solid content or homogeneity for a sample (Monakhova et al. 2015, Tadini et al. 2015, Bardy et al. 2008). In this work, the IRTF (InfraRed Fourier Transform) spectra were treated by an original algorithm developed to obtain the principal components of the IRTF spectra and their contributions for each sample. This bilinear decomposition used a PCA initialisation and the principal components were estimated from vectors calculated by PCA and linearly combined to provide non-negative signals minimizing a criterion based on cross-correlation. Hence, using this decomposition, it is possible to define IRTF signal of organic matter fractions like humic acid or fulvic acid depending on their origin like surface of depth of soil profiles. The method was used on a set of sample from Upper Negro River Basin (Amazon, Brazil) (Bueno,2009), where three soils sequences from surface to two meter depth containing 10 slices each. The sequences were sampled on a podzol well drain, a hydromorphic podzol and a cryptopodzol. From the IRTF data five representative component spectra were defined for all the extracted organic matter , and using other chemical composition information, a mechanism of organic matter fate is proposed to explain the observed results. Bardy, M., E. Fritsch, S. Derenne, T. Allard, N. R. do Nascimento, and G. T. Bueno. 2008. "Micromorphology and Spectroscopic Characteristics of Organic Matter in Waterlogged Podzols of the Upper Amazon Basin." Geoderma 145 (3-4): 222-30. Bueno, G.T. Appauvrissement et podzolisation des latérites du baissin du Rio Negro et gênese dês Podzols dans le haut bassin

  9. Fecal Microbiota Transplantation for Refractory Clostridium difficile Colitis in Solid Organ Transplant Recipients

    PubMed Central

    Friedman-Moraco, R. J.; Mehta, A. K.; Lyon, G. M.; Kraft, C. S.

    2015-01-01

    Fecal microbiota transplantation (FMT) has been shown to be safe and efficacious in individuals with refractory Clostridium difficile . It has not been widely studied in individuals with immunosuppression due to concerns about infectious complications. We describe two solid organ transplant recipients, one lung and one renal, in this case report that both had resolution of their diarrhea caused by C. difficile after FMT. Both recipients required two FMTs to achieve resolution of their symptoms and neither had infectious complications. Immunosuppressed individuals are at high risk for acquisition of C. difficile and close monitoring for infectious complications after FMT is necessary, but should not preclude its use in patients with refractory disease due to C. difficile . Sequential FMT may be used to achieve cure in these patients with damaged microbiota from antibiotic use and immunosuppression. PMID:24433460

  10. Shape-preserving transformations of organic matter and compositions thereof

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

    Kaehr, Bryan J.; Meyer, Kristin; Townson, Jason L.

    The present invention relates to methods of transforming organic matter into organic-inorganic composites, inorganic replicas, or conductive replicas. Organic matter, such as biological cells and tissue and organs, can be converted into such composites and replicas using the methods described herein. In particular, such methods transform organic matter (into inorganic, organic-inorganic, or conductive constructs), while simultaneously preserving microscopic and/or macroscopic structural detail.

  11. Spectral mapping of soil organic matter

    NASA Technical Reports Server (NTRS)

    Kristof, S. J.; Baumgardner, M. F.; Johannsen, C. J.

    1974-01-01

    Multispectral remote sensing data were examined for use in the mapping of soil organic matter content. Computer-implemented pattern recognition techniques were used to analyze data collected in May 1969 and May 1970 by an airborne multispectral scanner over a 40-km flightline. Two fields within the flightline were selected for intensive study. Approximately 400 surface soil samples from these fields were obtained for organic matter analysis. The analytical data were used as training sets for computer-implemented analysis of the spectral data. It was found that within the geographical limitations included in this study, multispectral data and automatic data processing techniques could be used very effectively to delineate and map surface soils areas containing different levels of soil organic matter.

  12. [Prevalence of target organ damage and factors associated with cardiovascular events in subjects with refractory hypertension].

    PubMed

    Armario, Pedro; Oliveras, Anna; Hernández Del Rey, Raquel; Poch, Esteban; Larrouse, María; Roca-Cusachs, Alex; de la Sierra, Alejandro

    2009-06-27

    To asses the prevalence of target organ damage (TOD) and factors associated with cardiovascular events in subjects with refractory hypertension. Cross-sectional study of 146 patients with clinical diagnosis of refractory hypertension. TOD was defined as the presence of microalbuminuria (MA), renal failure (RF), left ventricular hypertrophy (LVH) or left atrial enlargement (LAE). Cardiovascular events were defined as the antecedent of stroke, coronary heart disease, heart failure or peripheral arterial disease. 24-h ambulatory blood pressure monitoring was (ABPM) performed with a validated Spacelabs 90207. The prevalence of LVH was 62.3%, and LAE was observed in 27.7% of the subjects. The prevalence of RF was 28.1% and MA was found in 41,4%. An association between MA and LVH was observed. After adjusting by age, the urinary albumin excretion (UAE) correlated with clinical blood pressure (BP) and BP during 24-h ABPM, whereas LVMI correlated with ambulatory BP but not with clinical BP. The prevalence of previous cardiovascular events was 22% and in the multivariate regression analysis, UAE was the only independent factor associated with the antecedent of cardiovascular events. In subjects with refractory hypertension, the prevalence of TOD was high, and an association between heart and renal organ damage was observed. UAE was independently associated with the antecedent of cardiovascular disease.

  13. Soil organic matter composition affected by potato cropping managements

    USDA-ARS?s Scientific Manuscript database

    Organic matter is a small but important soil component. As a heterogeneous mixture of geomolecules and biomolecules, soil organic matter (SOM) can be fractionated into distinct pools with different solubility and lability. Water extractable organic matter (WEOM) fraction is the most labile and mobil...

  14. 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.

  15. Isolation and chemical characterization of dissolved and colloidal organic matter

    USGS Publications Warehouse

    Aiken, G.; Leenheer, J.

    1993-01-01

    Commonly used techniques for the concentration and isolation of organic matter from water, such as preparative chromatography, ultrafiltration and reverse osmosis, and the methods used to analyze the organic matter obtained by these methods are reviewed. The development of methods to obtain organic matter that is associated with fractions of the dissolved organic carbon other than humic substances, such as organic bases, hydrophilic organic acids and colloidal organic matter are discussed. Methods specifically used to study dissolved organic nitrogen and dissolved organic phosphorous are also discussed. -from Authors

  16. 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.

  17. Non-Destructive High-Resolution Organic Matter Record on Lake Sediment using Steady-State Solid Phase Fluorescence: Organic Matter Quality and Quantity Assessment.

    NASA Astrophysics Data System (ADS)

    Quiers, M.; Perrette, Y.; Etienne, D.; Develle, A. L.; Jacq, K.

    2017-12-01

    The use of organic proxies increases in paleoenvironmental reconstructions from natural archives. Major advances have been achieved by the development of new highly informative molecular proxies usually linked to specific compounds. While studies focused on targeted compounds, offering a high information degree, advances on bulk organic matter are limited. However, this bulk is the main contributor to carbon cycle and has been shown to be a driver of many mineral or organic compounds transfer and record. Development of target proxies need complementary information on bulk organic matter to understand biases link to controlling factors or analytical methods, and provide a robust interpretation. Fluorescence methods have often been employed to characterize and quantify organic matter. However, these technics are mainly developed for liquid samples, inducing material and resolution loss when working on natural archives (either stalagmite or sediments). High-resolution solid phase fluorescence (SPF) was developed on speleothems. This method allows now to analyse organic matter quality and quantity if procedure to constrain the optical density are adopted. In fact, a calibration method using liquid phase fluorescence (LPF) was developed for speleothem, allowing to quantify organic carbon at high-resolution. We report here an application of such a procedure SPF/LPF measurements on lake sediments. In order to avoid sediment matrix effects on the fluorescence signal, a calibration using LPF measurements was realised. First results using this method provided organic matter quality record of different organic matter compounds (humic-like, protein-like and chlorophylle-like compounds) at high resolution for the sediment core. High resolution organic matter fluxes are obtained in a second time, applying pragmatic chemometrics model (non linear models, partial least square models) on high resolution fluorescence data. SPF method can be considered as a promising tool for high

  18. Effects of chronic metal exposure and sediment organic matter on digestive absorption efficiency of cadmium by the deposit-feeding polychaete Capitella species I

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

    Selck, H.; Forbes, V.E.; Decho, A.W.

    1999-06-01

    Organic matter such as humic acid and bacterial slime exopolymer are common in estuarine and coastal sediments, where they are ingested by animals that process particulate detritus. Both humic acid (HA; refractory) and exopolymer (EPS; easily digestible) bind metals and therefore might represent a source of particulate-bound metals to deposit-feeding organisms. This study examined how cadmium preexposure, gut passage time (GPT), and quality and quantity of the organic coating on sediment particles interact to determine cadmium absorption efficiency (Cd-AE) in Capitella sp. I. Pulse-chase experiments using [sup 109]Cd and [sup 51]Cr were used to determine Cd-AE in individual worms. Wormsmore » were given a pulse of carbon-cleaned, HA-coated or EPS-coated sediment particles. The third treatment was divided into three EPS concentrations (high, medium, and low). A 5-d preexposure to cadmium did not affect the egestion rates during either the preexposure period or the chase phase. Worms given a pulse of carbon-cleaned particles exhibited higher egestion rates during the chase phase than worms given a pulse of organic-coated particles, and no differences were seen in egestion rate between worms exposed to HA- and high-EPS-coated particles. Egestion rates decreased with increasing EPS concentration. The presence of refractory organic material decreased the absorption efficiency of cadmium from sediment relative to Cd-AE from carbon-cleaned sediment but not relative to Cd-AE from sediment coated with a high concentration of EPS. The Cd-AE increased linearly with increasing exopolymer coating on sediment particles. Overall, Cd-AE increased with increasing gut passage time in worms that were not preexposed, although Cd-AE from HA-coated particles was independent of gut passage time. Preexposure to cadmium reversed the relationship between gut passage time and cadmium absorption efficiency. Thus, the implications are that sedimentary organic matter and worm physiology might

  19. Organic matter in hydrothermal metal ores and hydrothermal fluids

    USGS Publications Warehouse

    Orem, W.H.; Spiker, E. C.; Kotra, R.K.

    1990-01-01

    Massive polymetallic sulfides are currently being deposited around active submarine hydrothermal vents associated with spreading centers. Chemoautolithotrophic bacteria are responsible for the high production of organic matter also associated with modern submarine hydrothermal activity. Thus, there is a significant potential for organic matter/metal interactions in these systems. We have studied modern and ancient hydrothermal metal ores and modern hydrothermal fluids in order to establish the amounts and origin of the organic matter associated with the metal ores. Twenty-six samples from modern and ancient hydrothermal systems were surveyed for their total organic C contents. Organic C values ranged from 0.01% to nearly 4.0% in these samples. Metal ores from modern and ancient sediment-covered hydrothermal systems had higher organic C values than those from modern and ancient hydrothermal systems lacking appreciable sedimentary cover. One massive pyrite sample from the Galapagos spreading center (3% organic C) had stable isotope values of -27.4% (??13C) and 2.1% (??15N), similar to those in benthic siphonophors from active vents and distinct from seep sea sedimentary organic matter. This result coupled with other analyses (e.g. 13C NMR, pyrolysis/GC, SEM) of this and other samples suggests that much of the organic matter may originate from chemoautolithotrophic bacteria at the vents. However, the organic matter in hydrothermal metal ores from sediment covered vents probably arises from complex sedimentary organic matter by hydrothermal pyrolysis. The dissolved organic C concentrations of hydrothermal fluids from one site (Juan de Fuca Ridge) were found to be the same as that of background seawater. This result may indicate that dissolved organic C is effectively scavenged from hydrothermal fluids by biological activity or by co-precipitation with metal ores. ?? 1990.

  20. Accretion and Preservation of Organic Matter in Carbonaceous Chondrites as Revealed by NanoSIMS Imaging.

    NASA Astrophysics Data System (ADS)

    Remusat, L.; Guan, Y.; Eiler, J.

    2008-12-01

    Carbonaceous chondrites are the most primitive known meteorites. Their parent bodies accreted several discrete components of the early solar system: CAIs, other silicates, oxides, sulfides, ice, organics, and noble gases. Radioactive decay of short live radionucleides quickly heated these parent bodies and drove thermal metamorphism and aqueous alteration of their constituents. Despite this post-acretionary modification, at least some components of the organic matter in the carbaceous chondrites retained distinctive isotopic and molecular properties that may relate to their pre-acretionary origins in the protosolar nebula or in the molecular cloud that gave birth to it [1]. These processes that gave rise to early solar-system organic matter and the extent to which it was modified by parent body processes are still a matter of debate [2]. We have acquired NanoSIMS images of matrices of several CI, CM, CR and CV chondrites to document, in- situ, the distribution of organics and their textural and chemical relationships to co-existing inorganic components. Importantly, we performed these analyses on essentially unmodified fragments of matrix material pressed into indium, rather than on extracts, which have been the focus of most previous work on meteoritic organic matter. Specifically, we simultaneously collected H, D, 12C, 18O, 26CN, 28Si and 32S with a spatial resolution of 200 nm. Inorganic constituents of the imaged domains were determined by SEM imaging and EDS analysis. We identify two textural classes of organic constituents: diffuse organic matter and organic particles ~ 1 micron in diameter. The particles are common and do not exhibit any textural association with any inorganic matrix constituent. This distribution is consistent with previous observations by fluorescence optical microscopy [3]. These organic particles are likely primarily composed of insoluble organic matter (IOM) that grew prior to accretion as pure organic particules and was preserved in

  1. The influence of algal organic matter produced by Microcystis aeruginosa on coagulation-ultrafiltration treatment of natural organic matter.

    PubMed

    Xu, Jie; Zhao, Yanxia; Gao, Baoyu; Han, Songlin; Zhao, Qian; Liu, Xiaoli

    2018-04-01

    Cyanobacterial bloom causes the release of algal organic matter (AOM), which inevitably affects the treatment processes of natural organic matter (NOM). This study works on treating micro-polluted surface water (SW) by emerging coagulant, namely titanium sulfate (Ti(SO 4 ) 2 ), followed by Low Pressure Ultrafiltration (LPUF) technology. In particular, we explored the respective influence of extracellular organic matter (EOM) and intracellular organic matter (IOM) on synergetic EOM-NOM/IOM-NOM removal, functional mechanisms and subsequent filtration performance. Results show that the IOM inclusion in surface water body facilitated synergic IOM-NOM composite pollutants removal by Ti(SO 4 ) 2 , wherein loosely-aggregated flocs were produced, resulting in floc cake layer with rich porosity and permeability during LPUF. On the contrary, the surface water invaded by EOM pollutants increased Ti(SO 4 ) 2 coagulation burden, with substantially deteriorated both UV 254 -represented and dissolved organic matter (DOC) removal. Corresponded with the weak Ti(SO 4 ) 2 coagulation for EOM-NOM removal was the resultant serious membrane fouling during LPUF procedure, wherein dense cake layer was formed due to the compact structure of flocs. Although the IOM enhanced NOM removal with reduced Ti(SO 4 ) 2 dose and yielded mitigated membrane fouling, larger percentage of irreversible fouling was seen than NOM and EOM-NOM cases, which was most likely due to the substances with small molecular weight, such as microcystin, adhering in membrane pores. This research would provide theoretical basis for dose selection and process design during AOM-NOM water treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Self-organization of dissolved organic matter to micelle-like microparticles in river water.

    PubMed

    Kerner, Martin; Hohenberg, Heinz; Ertl, Siegmund; Reckermann, Marcus; Spitzy, Alejandro

    2003-03-13

    In aquatic systems, the concept of the 'microbial loop' is invoked to describe the conversion of dissolved organic matter to particulate organic matter by bacteria. This process mediates the transfer of energy and matter from dissolved organic matter to higher trophic levels, and therefore controls (together with primary production) the productivity of aquatic systems. Here we report experiments on laboratory incubations of sterile filtered river water in which we find that up to 25% of the dissolved organic carbon (DOC) aggregates abiotically to particles of diameter 0.4-0.8 micrometres, at rates similar to bacterial growth. Diffusion drives aggregation of low- to high-molecular-mass DOC and further to larger micelle-like microparticles. The chemical composition of these microparticles suggests their potential use as food by planktonic bacterivores. This pathway is apparent from differences in the stable carbon isotope compositions of picoplankton and the microparticles. A large fraction of dissolved organic matter might therefore be channelled through microparticles directly to higher trophic levels--bypassing the microbial loop--suggesting that current concepts of carbon conversion in aquatic systems require revision.

  3. Frontal gray matter abnormalities predict seizure outcome in refractory temporal lobe epilepsy patients.

    PubMed

    Doucet, Gaelle E; He, Xiaosong; Sperling, Michael; Sharan, Ashwini; Tracy, Joseph I

    2015-01-01

    Developing more reliable predictors of seizure outcome following temporal lobe surgery for intractable epilepsy is an important clinical goal. In this context, we investigated patients with refractory temporal lobe epilepsy (TLE) before and after temporal resection. In detail, we explored gray matter (GM) volume change in relation with seizure outcome, using a voxel-based morphometry (VBM) approach. To do so, this study was divided into two parts. The first one involved group analysis of differences in regional GM volume between the groups (good outcome (GO), e.g., no seizures after surgery; poor outcome (PO), e.g., persistent postoperative seizures; and controls, N = 24 in each group), pre- and post-surgery. The second part of the study focused on pre-surgical data only (N = 61), determining whether the degree of GM abnormalities can predict surgical outcomes. For this second step, GM abnormalities were identified, within each lobe, in each patient when compared with an ad hoc sample of age-matched controls. For the first analysis, the results showed larger GM atrophy, mostly in the frontal lobe, in PO patients, relative to both GO patients and controls, pre-surgery. When comparing pre-to-post changes, we found relative GM gains in the GO but not in the PO patients, mostly in the non-resected hemisphere. For the second analysis, only the frontal lobe displayed reliable prediction of seizure outcome. 81% of the patients showing pre-surgical increased GM volume in the frontal lobe became seizure free, post-surgery; while 77% of the patients with pre-surgical reduced frontal GM volume had refractory seizures, post-surgery. A regression analysis revealed that the proportion of voxels with reduced frontal GM volume was a significant predictor of seizure outcome (p = 0.014). Importantly, having less than 1% of the frontal voxels with GM atrophy increased the likelihood of being seizure-free, post-surgery, by seven times. Overall, our results suggest that using pre

  4. Frontal gray matter abnormalities predict seizure outcome in refractory temporal lobe epilepsy patients

    PubMed Central

    Doucet, Gaelle E.; He, Xiaosong; Sperling, Michael; Sharan, Ashwini; Tracy, Joseph I.

    2015-01-01

    Developing more reliable predictors of seizure outcome following temporal lobe surgery for intractable epilepsy is an important clinical goal. In this context, we investigated patients with refractory temporal lobe epilepsy (TLE) before and after temporal resection. In detail, we explored gray matter (GM) volume change in relation with seizure outcome, using a voxel-based morphometry (VBM) approach. To do so, this study was divided into two parts. The first one involved group analysis of differences in regional GM volume between the groups (good outcome (GO), e.g., no seizures after surgery; poor outcome (PO), e.g., persistent postoperative seizures; and controls, N = 24 in each group), pre- and post-surgery. The second part of the study focused on pre-surgical data only (N = 61), determining whether the degree of GM abnormalities can predict surgical outcomes. For this second step, GM abnormalities were identified, within each lobe, in each patient when compared with an ad hoc sample of age-matched controls. For the first analysis, the results showed larger GM atrophy, mostly in the frontal lobe, in PO patients, relative to both GO patients and controls, pre-surgery. When comparing pre-to-post changes, we found relative GM gains in the GO but not in the PO patients, mostly in the non-resected hemisphere. For the second analysis, only the frontal lobe displayed reliable prediction of seizure outcome. 81% of the patients showing pre-surgical increased GM volume in the frontal lobe became seizure free, post-surgery; while 77% of the patients with pre-surgical reduced frontal GM volume had refractory seizures, post-surgery. A regression analysis revealed that the proportion of voxels with reduced frontal GM volume was a significant predictor of seizure outcome (p = 0.014). Importantly, having less than 1% of the frontal voxels with GM atrophy increased the likelihood of being seizure-free, post-surgery, by seven times. Overall, our results suggest that using pre

  5. A simple approach to estimate daily loads of total, refractory, and labile organic carbon from their seasonal loads in a watershed

    Treesearch

    Ying Ouyang; Johnny M. Grace; Wayne C. Zipperer; Jeff Hatten; Janet Dewey

    2018-01-01

    Loads of naturally occurring total organic carbons (TOC), refractory organic carbon (ROC), and labile organic carbon (LOC) instreams control the availability of nutrients and the solubility and toxicity of contaminants and affect biological activities throughabsorption of light and complex metals with production of carcinogenic compounds....

  6. Isotopic compositions of cometary matter returned by Stardust.

    PubMed

    McKeegan, Kevin D; Aléon, Jerome; Bradley, John; Brownlee, Donald; Busemann, Henner; Butterworth, Anna; Chaussidon, Marc; Fallon, Stewart; Floss, Christine; Gilmour, Jamie; Gounelle, Matthieu; Graham, Giles; Guan, Yunbin; Heck, Philipp R; Hoppe, Peter; Hutcheon, Ian D; Huth, Joachim; Ishii, Hope; Ito, Motoo; Jacobsen, Stein B; Kearsley, Anton; Leshin, Laurie A; Liu, Ming-Chang; Lyon, Ian; Marhas, Kuljeet; Marty, Bernard; Matrajt, Graciela; Meibom, Anders; Messenger, Scott; Mostefaoui, Smail; Mukhopadhyay, Sujoy; Nakamura-Messenger, Keiko; Nittler, Larry; Palma, Russ; Pepin, Robert O; Papanastassiou, Dimitri A; Robert, François; Schlutter, Dennis; Snead, Christopher J; Stadermann, Frank J; Stroud, Rhonda; Tsou, Peter; Westphal, Andrew; Young, Edward D; Ziegler, Karen; Zimmermann, Laurent; Zinner, Ernst

    2006-12-15

    Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single (17)O-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is (16)O-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion.

  7. Research Highlight: Water-extractable organic matter from sandy loam soils

    USDA-ARS?s Scientific Manuscript database

    Labile organic matter plays important roles in soil health and nutrient cycling because of its dynamic nature. Water-extractable organic matter is part of the soil labile organic matter. In an article recently published in Agricultural & Environmental Letters, researchers report on the level and na...

  8. Dissolved organic matter reduces algal accumulation of methylmercury

    USGS Publications Warehouse

    Luengen, Allison C.; Fisher, Nicholas S.; Bergamaschi, Brian A.

    2012-01-01

    Dissolved organic matter (DOM) significantly decreased accumulation of methylmercury (MeHg) by the diatom Cyclotella meneghiniana in laboratory experiments. Live diatom cells accumulated two to four times more MeHg than dead cells, indicating that accumulation may be partially an energy-requiring process. Methylmercury enrichment in diatoms relative to ambient water was measured by a volume concentration factor (VCF). Without added DOM, the maximum VCF was 32 x 104, and the average VCF (from 10 to 72 h) over all experiments was 12.6 x 104. At very low (1.5 mg/L) added DOM, VCFs dropped by approximately half. At very high (20 mg/L) added DOM, VCFs dropped 10-fold. Presumably, MeHg was bound to a variety of reduced sulfur sites on the DOM, making it unavailable for uptake. Diatoms accumulated significantly more MeHg when exposed to transphilic DOM extracts than hydrophobic ones. However, algal lysate, a labile type of DOM created by resuspending a marine diatom in freshwater, behaved similarly to a refractory DOM isolate from San Francisco Bay. Addition of 67 μM L-cysteine resulted in the largest drop in VCFs, to 0.28 x 104. Although the DOM composition influenced the availability of MeHg to some extent, total DOM concentration was the most important factor in determining algal bioaccumulation of MeHg.

  9. Matrix protected organic matter in a river dominated margin: A possible mechanism to sequester terrestrial organic matter?

    NASA Astrophysics Data System (ADS)

    Mead, Ralph N.; Goñi, Miguel A.

    2008-06-01

    The provenance of organic matter in surface sediments from the northern Gulf of Mexico was investigated by analyzing the compositions of lipid biomarkers ( n-alkanes, fatty acids, sterols) liberated after a series of chemical treatments designed to remove different organo-mineral matrix associations (i.e. freely extractable, base-hydrolyzable, unhydrolyzable). Bulk analyses of the organic matter (carbon content, carbon:nitrogen ratios, stable and radiocarbon isotopic analyses) were also performed on the intact sediments and their non-hydrolyzable, demineralized residue. We found recognizable lipids from distinct sources, including terrestrial vascular plants, bacteria and marine algae and zooplankton, within each of the isolated fractions. Based on the lipid signatures and bulk compositions, the organic matter within the unhydrolyzable fractions appeared to be the most diagenetically altered, was the oldest in age, and had the highest abundance of terrigenous lipids. In contrast, the base-hydrolyzable fraction was the most diagentically unaltered, had the youngest ages and was most enriched in N and marine lipids. Our results indicate that fresh, autochthonous organic matter is the most important contributor to base-hydrolyzable lipids, whereas highly altered allochthonous sources appear to be predominant source of unhydrolyzable lipids in the surface sediments from the Atchafalaya River shelf. Overall, the lipid biomarker signatures of intact sediments were biased towards the autochthonous source because many of the organic compounds indicative of degraded, terrigenous sources were protected from extraction and saponification by organo-mineral matrices. It is only after these protective matrices were removed by treatment with HCl and HF that these compounds became evident.

  10. Measuring organic matter in Everglades wetlands and the Everglades Agricultural Area

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

    Wright, Alan L.; Hanlon, Edward A.

    Here, organic matter is a complex material that represents the long-term decay products from plants and other organisms in the soil. When organic matter is allowed to build up in a soil, the soil color at the surface usually turns a darker color, often with a red or brown hue. Typically in Florida mineral soils, organic matter content is quite low, within the range of 1 to 5%. However, in some soils that remain flooded for most of the year, organic matter can build up with time and actually become the soil. Such is the case for the organic soils,more » or histosols, found in southern Florida. These organic soils comprise much of the Water Conservation Areas, Everglades National Park (ENP), Big Cypress Basin, and the Everglades Agricultural Area (EAA). It is important to document organic matter accumulation in the Everglades to gauge the effectiveness of wetland creation and succession. For the EAA, the drained soils lose organic matter due to oxidation, so measurement of the organic matter content of these soils over the course of time indicates the oxidation potential and mineral incorporation from bedrock. Due to the wide diversity of soil types and methods of measuring soil organic matter, there is a need to devise a more universal method applicable to many types of histosols in south Florida. The intent of this publication is: 1.To describe a simple laboratory method for determining the organic matter content of the organic soils of southern Florida and demonstrate the importance of using this new procedure for improved accuracy and precision; 2.To utilize this updated laboratory procedure for field sites across Everglades wetlands and the EAA; and 3. To recommend this procedure be used by growers, state and federal agencies, and university and agency researchers dealing with the management of organic soils in southern Florida. Growers can use this improvement to organic matter measurement to keep lab testing costs low while getting a better, more

  11. Mercury dilution by autochthonous organic matter in a fertilized mangrove wetland.

    PubMed

    Machado, Wilson; Sanders, Christian J; Santos, Isaac R; Sanders, Luciana M; Silva-Filho, Emmanoel V; Luiz-Silva, Wanilson

    2016-06-01

    A dated sediment core from a highly-fertilized mangrove wetland located in Cubatão (SE Brazil) presented a negative correlation between mercury (Hg) and organic carbon contents. This is an unusual result for a metal with well-known affinity to organic matter. A dilution of Hg concentrations by autochthonous organic matter explained this observation, as revealed by carbon stable isotopes signatures (δ(13)C). Mercury dilution by the predominant mangrove-derived organic matter counterbalanced the positive influences of algal-derived organic matter and clay contents on Hg levels, suggesting that deleterious effects of Hg may be attenuated. Considering the current paradigm on the positive effect of organic matter on Hg concentrations in coastal sediments and the expected increase in mangrove organic matter burial due to natural and anthropogenic stimulations of primary production, predictions on the influences of organic matter on Hg accumulation in mangrove wetlands deserve caution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Distribution, Source and Fate of Dissolved Organic Matter in Shelf Seas

    NASA Astrophysics Data System (ADS)

    Carr, N.; Mahaffey, C.; Hopkins, J.; Sharples, J.; Williams, R. G.; Davis, C. E.

    2016-02-01

    Dissolved organic matter (DOM) is a complex array of molecules containing carbon (DOC), nitrogen (DON) and phosphorous (DOP), and represents the largest pool of organic matter in the marine environment. DOM in the sea originates from a variety of sources, including allochthonous inputs of terrestrial DOM from land via rivers, and autochthonous inputs through in-situ biotic processes that include phytoplankton exudation, grazing and cell lysis. Marine DOM is a substrate for bacterial growth and can act as a source of nutrients for autotrophs. However, a large component of DOM is biologically refractory. This pool is carbon-rich and nutrient-poor, and can transport and store its compositional elements over large areas and on long time scales. The role of DOM in the shelf seas is currently unclear, despite these regions acting as conduits between the land and open ocean, and also being highly productive ecosystems. Using samples collected across the Northwest European Shelf Sea, we studied the distribution, source, seasonality and potential fate of DOM using a combination of analytical tools, including analysis of amino acids, DOM absorbance spectra and excitation emission matrices, in conjunction with parallel factor analysis (PARAFAC). Strong cross shelf and seasonal gradients in DOM source and lability were found. We observed a strong seasonally dependent significant correlation between salinity and terrestrial DOM in the bottom mixed layer, an enrichment of DOM at the shelf edge in winter and a three-fold increase in fresh marine DOM coinciding with the timing of a spring bloom. Together, our findings illustrate the dynamic nature of DOM in shelf seas over a seasonal cycle and, highlight the potential for DOM to play a key role in the carbon cycle in these regions.

  13. Diversity of bacterial communities and dissolved organic matter in a temperate estuary.

    PubMed

    Osterholz, Helena; Kirchman, David L; Niggemann, Jutta; Dittmar, Thorsten

    2018-06-14

    Relationships between bacterial community and dissolved organic matter (DOM) include microbial uptake, transformation and secretion, all of which influence DOM composition. In this study, we explore diversity and similarity metrics of dissolved organic molecules (Fourier-transform ion cyclotron resonance mass spectrometry) and bacterial communities (tag-sequencing of 16S rRNA genes) along the salinity gradient of the Delaware Estuary (USA). We found that even though mixing, discharge and seasonal changes explained most of the variation in DOM and bacterial communities, there was still a relationship, albeit weak, between the composition of DOM and bacterial communities in the estuary. Overall, many DOM molecular formulas (MFs) and bacterial operational taxonomic units (OTUs) reoccurred over years and seasons while the frequency of MF-OTU correlations varied. Diversity based on MFs and OTUs was significantly correlated, decreasing towards the open ocean. However, while the diversity of bacterial OTUs dropped markedly with low salinity, MF diversity decreased strongly only at high salinities. We hypothesize that the different turnover times of DOM and bacteria lead to different abundance distributions of OTUs and MFs. A significant portion of the detected DOM is of a more refractory nature with lifetimes largely exceeding the mixing time of the estuary, while bacterial community turnover times in the Delaware Estuary are estimated at several days.

  14. Characteristics of dissolved organic matter in the Upper Klamath River, Lost River, and Klamath Straits Drain, Oregon and California

    USGS Publications Warehouse

    Goldman, Jami H.; Sullivan, Annett B.

    2017-12-11

    Concentrations of particulate organic carbon (POC) and dissolved organic carbon (DOC), which together comprise total organic carbon, were measured in this reconnaissance study at sampling sites in the Upper Klamath River, Lost River, and Klamath Straits Drain in 2013–16. Optical absorbance and fluorescence properties of dissolved organic matter (DOM), which contains DOC, also were analyzed. Parallel factor analysis was used to decompose the optical fluorescence data into five key components for all samples. Principal component analysis (PCA) was used to investigate differences in DOM source and processing among sites.At all sites in this study, average DOC concentrations were higher than average POC concentrations. The highest DOC concentrations were at sites in the Klamath Straits Drain and at Pump Plant D. Evaluation of optical properties indicated that Klamath Straits Drain DOM had a refractory, terrestrial source, likely extracted from the interaction of this water with wetland peats and irrigated soils. Pump Plant D DOM exhibited more labile characteristics, which could, for instance, indicate contributions from algal or microbial exudates. The samples from Klamath River also had more microbial or algal derived material, as indicated by PCA analysis of the optical properties. Most sites, except Pump Plant D, showed a linear relation between fluorescent dissolved organic matter (fDOM) and DOC concentration, indicating these measurements are highly correlated (R2=0.84), and thus a continuous fDOM probe could be used to estimate DOC loads from these sites.

  15. Molecular Analyzer for Complex Refractory Organic-Rich Surfaces (MACROS)

    NASA Technical Reports Server (NTRS)

    Getty, Stephanie A.; Cook, Jamie E.; Balvin, Manuel; Brinckerhoff, William B.; Li, Xiang; Grubisic, Andrej; Cornish, Timothy; Ferrance, Jerome; Southard, Adrian

    2017-01-01

    The Molecular Analyzer for Complex Refractory Organic-rich Surfaces, MACROS, is a novel instrument package being developed at NASA Goddard Space Flight Center. MACROS enables the in situ characterization of a sample's composition by coupling two powerful techniques into one compact instrument package: (1) laser desorption/ionization time-of-flight mass spectrometry (LDMS) for broad detection of inorganic mineral composition and non-volatile organics, and (2) liquid-phase extraction methods to gently isolate the soluble organic and inorganic fraction of a planetary powder for enrichment and detailed analysis by liquid chromatographic separation coupled to LDMS. The LDMS is capable of positive and negative ion detection, precision mass selection, and fragment analysis. Two modes are included for LDMS: single laser LDMS as the broad survey mode and two step laser mass spectrometry (L2MS). The liquid-phase extraction will be done in a newly designed extraction module (EM) prototype, providing selectivity in the analysis of a complex sample. For the sample collection, a diamond drill front end will be used to collect rock/icy powder. With all these components and capabilities together, MACROS offers a versatile analytical instrument for a mission targeting an icy moon, carbonaceous asteroid, or comet, to fully characterize the surface composition and advance our understanding of the chemical inventory present on that body.

  16. GROUNDWATER TRANSPORT OF HYDROPHOBIC ORGANIC COMPOUNDS IN THE PRESENCE OF DISSOLVED ORGANIC MATTER

    EPA Science Inventory

    The effects of dissolved organic matter (DOM) on the transport of hydrophobic organic compounds in soil columns were investigated. Three compounds (naphthalene, phenanthrene and DDT) that spanned three orders of magnitude in water solubility were used. Instead of humic matter, mo...

  17. Opposing effects of different soil organic matter fractions on crop yields.

    PubMed

    Wood, Stephen A; Sokol, Noah; Bell, Colin W; Bradford, Mark A; Naeem, Shahid; Wallenstein, Matthew D; Palm, Cheryl A

    2016-10-01

    Soil organic matter is critical to sustainable agriculture because it provides nutrients to crops as it decomposes and increases nutrient- and water-holding capacity when built up. Fast- and slow-cycling fractions of soil organic matter can have different impacts on crop production because fast-cycling fractions rapidly release nutrients for short-term plant growth and slow-cycling fractions bind nutrients that mineralize slowly and build up water-holding capacity. We explored the controls on these fractions in a tropical agroecosystem and their relationship to crop yields. We performed physical fractionation of soil organic matter from 48 farms and plots in western Kenya. We found that fast-cycling, particulate organic matter was positively related to crop yields, but did not have a strong effect, while slower-cycling, mineral-associated organic matter was negatively related to yields. Our finding that slower-cycling organic matter was negatively related to yield points to a need to revise the view that stabilization of organic matter positively impacts food security. Our results support a new paradigm that different soil organic matter fractions are controlled by different mechanisms, potentially leading to different relationships with management outcomes, like crop yield. Effectively managing soils for sustainable agriculture requires quantifying the effects of specific organic matter fractions on these outcomes. © 2016 by the Ecological Society of America.

  18. Effect of photodegradation and biodegradation on the concentration and composition of dissolved organic matter in diverse waterbodies

    NASA Astrophysics Data System (ADS)

    Manalilkada Sasidharan, S.; Dash, P.; Singh, S.; Lu, Y.

    2017-12-01

    The objective of this research was to quantify the effects of photodegradation and biodegradation on the dissolved organic matter (DOM) concentration and composition in five distinct waterbodies with diverse types of watershed land use and land cover in the southeastern United States. The water bodies included an agricultural pond, a lake in a predominantly forested watershed, a man-made reservoir, an estuary, and a bay. Two sets of samples were prepared from these water bodies by dispensing filtered water samples to unfiltered samples in 10:1 ratio. The first set was kept in the sunlight during the day (12 hours), and colored dissolved organic matter (CDOM) absorption and fluorescence were measured periodically over a 30-day period for examining the effects of combined photo- and biodegradation. The second set of samples was kept in the dark for examining the effects of biodegradation alone, and CDOM absorption and fluorescence were measured at the same time as the sunlight-exposed samples. Subsequently, spectrometric results in tandem with multivariate statistical analysis were used to interpret the lability vs. composition of DOM. Parallel factor analysis (PARAFAC) revealed the presence of four DOM components (C1-C4). C1 and C4 were microbial tryptophan-like, labile lighter components, while C2 and C3 were terrestrial humic like or fulvic acid type, larger aromatic refractory components. The principal component analysis (PCA) also revealed two distinct groups of DOM - C1 and C4 vs. C2 and C3. The negative PC1 loadings of C2, C3, HIX, a254 and SUVA indicated humic-like or fulvic-like structurally complex refractory aromatic DOM originated from higher plants in forested areas. C1, C4, SR, FI and BI had positive PC1 loadings, which indicated structurally simpler labile DOM were derived from agricultural areas or microbial activity. There was a decrease in dissolved organic carbon (DOC) due to combined photo- and biodegradation, and transformation of components C2

  19. Defining organic matter quality in sediment systems: a suggested classification scheme

    NASA Astrophysics Data System (ADS)

    Alderson, Danielle; Evans, Martin; Rothwell, James; Boult, Stephen

    2015-04-01

    The quantity and quality of the mineral component of sediments is a core focus of sedimentological investigation in terrestrial systems. This is not to say that the organic component of collected sediments is simply ignored; the organic component is often scrutinised, but in some fields in a restricted manner, limited to basic characteristics such as the ratio of organic to mineral content derived from loss on ignition. There is no doubt that this information is useful; however, these types of analysis indicate the quantity of organic matter relative to a particular temporal scale or volume, rather than treating the organic fraction as a separate entity worthy of substantial investigation. The quality of the organic component is being increasingly considered in a number of fields, with molecular, thermal, spectroscopic and bulk methods being used. However, models and theories on organic matter processing in a variety of environmental systems, have been developed without clearly defining organic matter quality, because most results do not depend on an outright measure of quality (Bosatta and Agren, 1999). With approaches and techniques varying between fields, there is a need to consider a more systematic approach to the analysis and definition of organic matter quality. The disparities in the definition of the quality of organic matter, and thus how it may be measured have vital implications for the study of carbon cycling, biogeochemical processing, and ultimately ecosystem structure and function. The quality and quantity of organic matter have an influence on the chemistry and biology of systems and may reveal a wealth of past or contemporary environmental information. In this paper we provide a classification of organic matter quality and examples of potential applications and suitable techniques for the analysis of the main classes of organic matter character. A more consistent approach to organic matter characterisation has the potential to aid understanding of

  20. Carotenoids are the likely precursor of a significant fraction of marine dissolved organic matter

    PubMed Central

    Arakawa, Neal; Aluwihare, Lihini I.; Simpson, Andre J.; Soong, Ronald; Stephens, Brandon M.; Lane-Coplen, Daniel

    2017-01-01

    The ocean’s biota sequester atmospheric carbon dioxide (CO2) in part by producing dissolved organic matter (DOM) that persists in the ocean for millennia. This long-term accumulation of carbon may be facilitated by abiotic and biotic production of chemical structures that resist degradation, consequently contributing disproportionately to refractory DOM. Compounds that are selectively preserved in seawater were identified in solid-phase extracted DOM (PPL-DOM) using comprehensive gas chromatography (GC) coupled to mass spectrometry (MS). These molecules contained cyclic head groups that were linked to isoprenoid tails, and their overall structures closely resembled carotenoid degradation products (CDP). The origin of these compounds in PPL-DOM was further confirmed with an in vitro β-carotene photooxidation experiment that generated water-soluble CDP with similar structural characteristics. The molecular-level identification linked at least 10% of PPL-DOM carbon, and thus 4% of total DOM carbon, to CDP. Nuclear magnetic resonance spectra of experimental CDP and environmental PPL-DOM overlapped considerably, which indicated that even a greater proportion of PPL-DOM was likely composed of CDP. The CDP-rich DOM fraction was depleted in radiocarbon (14C age > 1500 years), a finding that supports the possible long-term accumulation of CDP in seawater. By linking a specific class of widespread biochemicals to refractory DOM, this work provides a foundation for future studies that aim to examine how persistent DOM forms in the ocean. PMID:28959723

  1. Molecular formulae of marine and terrigenous dissolved organic matter detected by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

    NASA Astrophysics Data System (ADS)

    Koch, Boris P.; Witt, Matthias; Engbrodt, Ralph; Dittmar, Thorsten; Kattner, Gerhard

    2005-07-01

    The chemical structure of refractory marine dissolved organic matter (DOM) is still largely unknown. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS) was used to resolve the complex mixtures of DOM and provide valuable information on elemental compositions on a molecular scale. We characterized and compared DOM from two sharply contrasting aquatic environments, algal-derived DOM from the Weddell Sea (Antarctica) and terrigenous DOM from pore water of a tropical mangrove area in northern Brazil. Several thousand molecular formulas in the mass range of 300-600 Da were identified and reproduced in element ratio plots. On the basis of molecular elemental composition and double-bond equivalents (DBE) we calculated an average composition for marine DOM. O/C ratios in the marine samples were lower (0.36 ± 0.01) than in the mangrove pore-water sample (0.42). A small proportion of chemical formulas with higher molecular mass in the marine samples were characterized by very low O/C and H/C ratios probably reflecting amphiphilic properties. The average number of unsaturations in the marine samples was surprisingly high (DBE = 9.9; mangrove pore water: DBE = 9.4) most likely due to a significant contribution of carbonyl carbon. There was no significant difference in elemental composition between surface and deep-water DOM in the Weddell Sea. Although there were some molecules with unique marine elemental composition, there was a conspicuous degree of similarity between the terrigenous and algal-derived end members. Approximately one third of the molecular formulas were present in all marine as well as in the mangrove samples. We infer that different forms of microbial degradation ultimately lead to similar structural features that are intrinsically refractory, independent of the source of the organic matter and the environmental conditions where degradation took place.

  2. Fluorescence spectroscopy for monitoring reduction of natural organic matter and halogenated furanone precursors by biofiltration.

    PubMed

    Peleato, Nicolás M; McKie, Michael; Taylor-Edmonds, Lizbeth; Andrews, Susan A; Legge, Raymond L; Andrews, Robert C

    2016-06-01

    The application of fluorescence spectroscopy to monitor natural organic matter (NOM) reduction as a function of biofiltration performance was investigated. This study was conducted at pilot-scale where a conventional media filter was compared to six biofilters employing varying enhancement strategies. Overall reductions of NOM were identified by measuring dissolved organic carbon (DOC), and UV absorbance at 254 nm, as well as characterization of organic sub-fractions by liquid chromatography-organic carbon detection (LC-OCD) and parallel factors analysis (PARAFAC) of fluorescence excitation-emission matrices (FEEM). The biofilter using granular activated carbon media, with exhausted absorptive capacity, was found to provide the highest removal of all identified PARAFAC components. A microbial or processed humic-like component was found to be most amenable to biodegradation by biofilters and removal by conventional treatment. One refractory humic-like component, detectable only by FEEM-PARAFAC, was not well removed by biofiltration or conventional treatment. All biofilters removed protein-like material to a high degree relative to conventional treatment. The formation potential of two halogenated furanones, 3-chloro-4(dichloromethyl)-2(5H)-furanone (MX) and mucochloric acid (MCA), as well as overall treated water genotoxicity are also reported. Using the organic characterization results possible halogenated furanone and genotoxicity precursors are identified. Comparison of FEEM-PARAFAC and LC-OCD results revealed polysaccharides as potential MX/MCA precursors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Biodesulfurization of refractory organic sulfur compounds in fossil fuels.

    PubMed

    Soleimani, Mehran; Bassi, Amarjeet; Margaritis, Argyrios

    2007-01-01

    The stringent new regulations to lower sulfur content in fossil fuels require new economic and efficient methods for desulfurization of recalcitrant organic sulfur. Hydrodesulfurization of such compounds is very costly and requires high operating temperature and pressure. Biodesulfurization is a non-invasive approach that can specifically remove sulfur from refractory hydrocarbons under mild conditions and it can be potentially used in industrial desulfurization. Intensive research has been conducted in microbiology and molecular biology of the competent strains to increase their desulfurization activity; however, even the highest activity obtained is still insufficient to fulfill the industrial requirements. To improve the biodesulfurization efficiency, more work is needed in areas such as increasing specific desulfurization activity, hydrocarbon phase tolerance, sulfur removal at higher temperature, and isolating new strains for desulfurizing a broader range of sulfur compounds. This article comprehensively reviews and discusses key issues, advances and challenges for a competitive biodesulfurization process.

  4. Influence of anoxic pore water dissolved organic matter on the fate and transport of hydrophobic organic pollutants

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

    Hunchak-Kariouk, K.

    1992-01-01

    Pore water dissolved organic matter is an overlooked pool of organic matter important to the environmental fate of hydrophobic organic pollutants. The association of polychlorinated biphenyls, polyaromatic hydrocarbons and chlorinated pesticides with pore water dissolved organic matter influences their distribution and mobility within the bottom sediment environment. Steep physical, biological and chemical gradients at the sediment/water interface isolate the pore water and create unique conditions within the sediment. This study indicates that any disturbance of this environment will alter the distribution and mobility of organic pollutants by changing their association to the pore water dissolved organic matter. A small volumemore » closed equilibration method was developed to measure the solubility enhancement of 2,2' 4,4'-tetrachlorobiphenyl (TeCB) by natural dissolved organic matter. Chemical coated micro-glass beads were equilibrated with anoxic and laboratory aerated (oxic) pore water samples in flame sealed ampules. The TeCB enhanced solubilities were used to determine the pore water dissolved organic matter partition coefficient, K[sub pwdom]. The measured TeCB solubility and K[sub pwdom] were much smaller for anoxic than oxic pore waters. The dissolved organic matter sorptive capacity for the TeCB increased as the water was aerated. This change is attributed to coagulative fractionation and structural changes of the pore water dissolved organic matter during aeration and was characterized by differences in the dissolved organic matter concentration, UV absorption at 254 nm, interfacial surface tension, and sorption capacity of molecular weight fractions of anoxic and oxic pore water dissolved organic matter. The increase in partitioning indicates that there will be an increase in the mobility of the TeCB as an anoxic bottom sediment environment is disturbed and aerated.« less

  5. High dimensional reflectance analysis of soil organic matter

    NASA Technical Reports Server (NTRS)

    Henderson, T. L.; Baumgardner, M. F.; Franzmeier, D. P.; Stott, D. E.; Coster, D. C.

    1992-01-01

    Recent breakthroughs in remote-sensing technology have led to the development of high spectral resolution imaging sensors for observation of earth surface features. This research was conducted to evaluate the effects of organic matter content and composition on narrowband soil reflectance across the visible and reflective infrared spectral ranges. Organic matter from four Indiana agricultural soils, ranging in organic C content from 0.99 to 1.72 percent, was extracted, fractionated, and purified. Six components of each soil were isolated and prepared for spectral analysis. Reflectance was measured in 210 narrow bands in the 400- to 2500-nm wavelength range. Statistical analysis of reflectance values indicated the potential of high dimensional reflectance data in specific visible, near-infrared, and middle-infrared bands to provide information about soil organic C content, but not organic matter composition. These bands also responded significantly to Fe- and Mn-oxide content.

  6. Fluctuations of dissolved organic matter in river used for drinking water and impacts on conventional treatment plant performance.

    PubMed

    Volk, Christian; Kaplan, Louis A; Robinson, Jeff; Johnson, Bruce; Wood, Larry; Zhu, Hai Wei; LeChevallier, Mark

    2005-06-01

    Natural organic matter (NOM) in drinking water supplies can provide precursors for disinfectant byproducts, molecules that impact taste and odors, compounds that influence the efficacy of treatment, and other compounds that are a source of energy and carbon for the regrowth of microorganisms during distribution. NOM, measured as dissolved organic carbon (DOC), was monitored daily in the White River and the Indiana-American water treatment plant over 22 months. Other parameters were either measured daily (UV-absorbance, alkalinity, color, temperature) or continuously (turbidity, pH, and discharge) and used with stepwise linear regressions to predict DOC concentrations. The predictive models were validated with monthly samples of the river water and treatment plant effluent taken over a 2-year period after the daily monitoring had ended. Biodegradable DOC (BDOC) concentrations were measured in the river water and plant effluent twice monthly for 18 months. The BDOC measurements, along with measurements of humic and carbohydrate constituents within the DOC and BDOC pools, revealed that carbohydrates were the organic fraction with the highest percent removal during treatment, followed by BDOC, humic substances, and refractory DOC.

  7. Adsorption of natural dissolved organic matter at the oxide/water interface

    USGS Publications Warehouse

    Davis, James A.

    1982-01-01

    Natural organic matter is readily adsorbed by alumina and kaolinite in the pH range of natural waters. Adsorption occurs by complex formation between surface hydroxyls and the acidic functional groups of the organic matter. Oxides with relatively acidic surface hydroxyls, e.g. silica, do not react strongly with the organic matter. Under conditions typical for natural waters, almost complete surface coverage by adsorbed organic matter may be expected for alumina, hydrous iron oxides and the edge sites of aluminosilicates. Potentiometric titration and electrophoresis indicate that most of the acidic functional groups of the adsorbed organic matter are neutralized by protons from solution. The organic coating is expected to have a great influence on subsequent adsorption of inorganic cations and anions.

  8. Influence of land use on soil organic matter

    NASA Astrophysics Data System (ADS)

    Rogeon, H.; Lemée, L.; Chabbi, A.; Ambles, A.

    2009-04-01

    Soil organic matter (SOM) is actually of great environmental interest as the amount of organic matter stored in soils represents one of the largest reservoirs of organic carbon on the global scale [1]. Indeed, soil carbon storage capacity represents 1500 to 2000 Gt for the first meter depth, which is twice the concentration of atmospheric CO2 [2]. Furthermore, human activities, such as deforestation (which represents a flux of 1.3 Gt C/year), contribute to the increase in atmospheric CO2 concentration for about one percent a year [3]. Therefore, carbon dioxide sequestration in plant and carbon storage in soil and biomass could be considered as a complementary solution against climate change. The stock of carbon in soils is greatly influenced by land use (ca 70 Gt for a forest soil or a grassland against 40 Gt for an arable land). Furthermore the molecular composition of SOM should be also influenced by vegetation. In this context, four horizons taken between 0-120 cm from the same profile of a soil under grassland and forest located in the vicinity of Poitiers (INRA Lusignan, ORE Prairie) were compared. For the surface horizon, the study is improved with the results from the cultivated soil from INRA Versailles. Soil organic matter was characterized using IR spectroscopy, elemental analysis and thermal analysis. Granulometric fractionation into sand (50-2000 μm), silt (2-50 μm) and clay (<2 μm) was conducted. The organic matter associated with the mineral fractions was thus characterized using thermochemolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS). The total lipidic fractions were extracted with CH2Cl2/MeOH using an accelerated solvent extraction (ASE). In the three soils, lipids are concentrated into the superficial horizon (0-30 cm) which indicates a low mobilisation. Lipids from the superficial horizon are more abundant for the arable soil (1010 ppm) than for the two other (400 ppm). Lipids from the forest and the grassland were

  9. Evolution of molecular weight and fluorescence of effluent organic matter (EfOM) during oxidation processes revealed by advanced spectrographic and chromatographic tools.

    PubMed

    Chen, Zhiqiang; Li, Mo; Wen, Qinxue; Ren, Nanqi

    2017-11-01

    Effluent organic matter (EfOM) is an emerging concern to receiving aquatic environment due to its refractory property. The degradation of EfOM in ozonation and other two advanced oxidation processes (AOPs), UV/H 2 O 2 and UV/persulfate (PS), was investigated in this study. Fluorescence spectra coupled with parallel factor analysis (PARAFAC) and two-dimensional correlation gel permeation chromatography (2D-GPC) were used to track the evolution of EfOM during each oxidation process. Results showed that the degradation of EfOM indicated by dissolved organic carbon (DOC), UV 254 and fluorescence components, fitted well with pseudo-first-order kinetic model during the oxidation processes. Ozonation showed higher degradation efficiency than AOPs, while UV/PS was more effective than UV/H 2 O 2 with equimolar oxidants dosage. Ozone and SO· 4 - were more reactive with terrestrial humic-like substances, while hydroxyl radical preferentially reacted with protein-like substances. Organic molecules with higher molecular weight (MW) were susceptible to ozone or radicals. Ozonation could transform higher MW (MW of 3510 and 575) organic matters into lower MW organic matters (MW of 294), while reductions of all the organics were observed in both AOPs. Due to the higher reaction rates between ozone and EfOM, ozonation maybe serve as a pre-treatment for AOPs to reduce the radical and energy consumption and improve mineralization of EfOM by AOPs. The decline in DOC, UV 254 , fluorescence and reduction in oxidants increased with the increase of oxidants dosage, and linear correlations among them were found during the ozonation and AOPs. Copyright © 2017. Published by Elsevier Ltd.

  10. Composition and Biolability of Dissolved Organic Matter Leached from the Dominant Endmembers of the Siberian Arctic

    NASA Astrophysics Data System (ADS)

    Borgen, M.; Spencer, R. G.; Mann, P. J.; Vonk, J. E.; Bulygina, E. B.; Holmes, R. M.

    2012-12-01

    Terrigenous dissolved organic matter (DOM) has historically been thought to be refractory as it is mobilized into and transported through Arctic fluvial networks. However, a growing body of evidence suggests that this DOM, largely leached from vegetation, soils, and litter during the annual freshet, is highly biolabile. This study examined DOM leached from these dominant endmembers of the Kolyma River watershed in the Siberian Arctic. As leachates progressed through time, measurements of dissolved organic carbon (DOC), optical parameters to assess DOM composition, and biodegradation incubations were undertaken. This suite of measurements allowed examination of the rate and composition of leached DOC into the aquatic system and quantification of the biolability of the DOM from the diverse range of endmembers examined. Of all the endmembers, vascular plants leached the greatest amount of DOC and results will be presented relating DOC concentration and DOM composition to initial source material. Furthermore, controls on DOM biolability, enzymatic activity, and the ultimate fate of terriginous DOC in Siberian fluvial systems will be discussed.

  11. Advanced solid-state NMR spectroscopy of natural organic matter.

    PubMed

    Mao, Jingdong; Cao, Xiaoyan; Olk, Dan C; Chu, Wenying; Schmidt-Rohr, Klaus

    2017-05-01

    Solid-state NMR is essential for the characterization of natural organic matter (NOM) and is gaining importance in geosciences and environmental sciences. This review is intended to highlight advanced solid-state NMR techniques, especially a systematic approach to NOM characterization, and their applications to the study of NOM. We discuss some basics of how to acquire high-quality and quantitative solid-state 13 C NMR spectra, and address some common technical mistakes that lead to unreliable spectra of NOM. The identification of specific functional groups in NOM, primarily based on 13 C spectral-editing techniques, is described and the theoretical background of some recently-developed spectral-editing techniques is provided. Applications of solid-state NMR to investigating nitrogen (N) in NOM are described, focusing on limitations of the widely used 15 N CP/MAS experiment and the potential of improved advanced NMR techniques for characterizing N forms in NOM. Then techniques used for identifying proximities, heterogeneities and domains are reviewed, and some examples provided. In addition, NMR techniques for studying segmental dynamics in NOM are reviewed. We also briefly discuss applications of solid-state NMR to NOM from various sources, including soil organic matter, aquatic organic matter, organic matter in atmospheric particulate matter, carbonaceous meteoritic organic matter, and fossil fuels. Finally, examples of NMR-based structural models and an outlook are provided. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. The Case Against Charge Transfer Interactions in Dissolved Organic Matter Photophysics.

    PubMed

    McKay, Garrett; Korak, Julie A; Erickson, Paul R; Latch, Douglas E; McNeill, Kristopher; Rosario-Ortiz, Fernando L

    2018-01-16

    The optical properties of dissolved organic matter influence chemical and biological processes in all aquatic ecosystems. Dissolved organic matter optical properties have been attributed to a charge-transfer model in which donor-acceptor complexes play a primary role. This model was evaluated by measuring the absorbance and fluorescence response of organic matter isolates to changes in solvent temperature, viscosity, and polarity, which affect the position and intensity of spectra for known donor-acceptor complexes of organic molecules. Absorbance and fluorescence spectral shape were largely unaffected by these changes, indicating that the distribution of absorbing and emitting species was unchanged. Overall, these results call into question the wide applicability of the charge-transfer model for explaining organic matter optical properties and suggest that future research should explore other models for dissolved organic matter photophysics.

  13. Relationship between soluble microbial products (SMP) and effluent organic matter (EfOM): characterized by fluorescence excitation emission matrix coupled with parallel factor analysis.

    PubMed

    Yu, Huarong; Qu, Fangshu; Sun, Lianpeng; Liang, Heng; Han, Zhengshuang; Chang, Haiqing; Shao, Senlin; Li, Guibai

    2015-02-01

    Effluent organic matter (EfOM) originating from wastewater treatment plant (WWTP) is of significant concern, as it not only influences the discharge quality of WWTP but also exerts a significant effect on the efficiency of the downstream advanced treatment facilities. Soluble microbial products (SMP) is a major part of EfOM. In order to further understand the relationship between soluble microbial products (SMP) and EfOM, and in turn, to propose measures for EfOM control, the formation of SMP and EfOM in identical activated sludge sequencing batch reactors (SBR) with different feed water was investigated using fluorescence excitation and emission spectroscopy matrix coupled with parallel factor analysis (EEM-PARAFAC) as well as other organic matter quantification tools. Results showed that EfOM contained not only SMP but also a considerable amount of allochthonous organic matter that derived not merely from natural organic matter (NOM). Four components in EfOM/SMP were identified by EEM-PARAFAC. Tyrosine-like substances in EfOM (Component 3, λex/em=270/316 nm) were mainly originated from utilization associated products (UAP) of SMP. Tryptophan-like substances (Component 2, λex/em=280/336 nm) as well as fulvic-like and humic-like substances in EfOM (Component 1, λex/em=240(290)/392 nm and Component 4, λex/em=260(365)/444 nm) were majorly derived from the refractory substances introduced along with the influent, among which Component 2 was stemmed from sources other than NOM. As solid retention time (SRT) increased, Component 2 and polysaccharides in SMP/EfOM decreased, while Component 4 in SMP increased. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Factors influencing organic carbon preservation in marine sediments

    NASA Technical Reports Server (NTRS)

    Canfield, D. E.

    1994-01-01

    The organic matter that escapes decomposition is buried and preserved in marine sediments, with much debate as to whether the amount depends on bottom-water O2 concentration. One group argues that decomposition is more efficient with O2, and hence, organic carbon will be preferentially oxidized in its presence, and preserved in its absence. Another group argues that the kinetics of organic matter decomposition are similar in the presence and absence of O2, and there should be no influence of O2 on preservation. A compilation of carbon preservation shows that both groups are right, depending on the circumstances of deposition. At high rates of deposition, such as near continental margins, little difference in preservation is found with varying bottom-water O2. It is important that most carbon in these sediments decomposes by anaerobic pathways regardless of bottom-water O2. Hence, little influence of bottom-water O2 on preservation would, in fact, be expected. As sedimentation rate drops, sediments deposited under oxygenated bottom water become progressively more aerobic, while euxinic sediments remain anaerobic. Under these circumstances, the relative efficiencies of aerobic and anaerobic decomposition could affect preservation. Indeed, enhanced preservation is observed in low-O2 and euxinic environments. To explore in detail the factors contributing to this enhanced carbon preservation, aspects of the biochemistries of the aerobic and anaerobic process are reviewed. Other potential influences on preservation are also explored. Finally, a new model for organic carbon decomposition, the "pseudo-G" model, is developed. This model couples the degradation of refractory organic matter to the overall metabolic activity of the sediment, and has consequences for carbon preservation due to the mixing together of labile and refractory organic matter by bioturbation.

  15. Evolution of Morphological and Physical Properties of Laboratory Interstellar Organic Residues with Ultraviolet Irradiation

    NASA Astrophysics Data System (ADS)

    Piani, L.; Tachibana, S.; Hama, T.; Tanaka, H.; Endo, Y.; Sugawara, I.; Dessimoulie, L.; Kimura, Y.; Miyake, A.; Matsuno, J.; Tsuchiyama, A.; Fujita, K.; Nakatsubo, S.; Fukushi, H.; Mori, S.; Chigai, T.; Yurimoto, H.; Kouchi, A.

    2017-03-01

    Refractory organic compounds formed in molecular clouds are among the building blocks of the solar system objects and could be the precursors of organic matter found in primitive meteorites and cometary materials. However, little is known about the evolutionary pathways of molecular cloud organics from dense molecular clouds to planetary systems. In this study, we focus on the evolution of the morphological and viscoelastic properties of molecular cloud refractory organic matter. We found that the organic residue, experimentally synthesized at ˜10 K from UV-irradiated H2O-CH3OH-NH3 ice, changed significantly in terms of its nanometer- to micrometer-scale morphology and viscoelastic properties after UV irradiation at room temperature. The dose of this irradiation was equivalent to that experienced after short residence in diffuse clouds (≤104 years) or irradiation in outer protoplanetary disks. The irradiated organic residues became highly porous and more rigid and formed amorphous nanospherules. These nanospherules are morphologically similar to organic nanoglobules observed in the least-altered chondrites, chondritic porous interplanetary dust particles, and cometary samples, suggesting that irradiation of refractory organics could be a possible formation pathway for such nanoglobules. The storage modulus (elasticity) of photo-irradiated organic residues is ˜100 MPa irrespective of vibrational frequency, a value that is lower than the storage moduli of minerals and ice. Dust grains coated with such irradiated organics would therefore stick together efficiently, but growth to larger grains might be suppressed due to an increase in aggregate brittleness caused by the strong connections between grains.

  16. Enhancement of the natural organic matter removal from drinking water by nanofiltration.

    PubMed

    Matilainen, A; Liikanen, R; Nyström, M; Lindqvist, N; Tuhkanen, T

    2004-03-01

    Finnish surface waters are abundant in natural organic matter. Natural organic matter can be removed from drinking water in a water treatment process by coagulation and filtration. The standard treatment operations are not able to remove the smallest molar mass fraction of organic matter and the intermediate molar mass matter is only partly removed. The removal of residual natural organic matter from drinking water by nanofiltration was evalueted in this study. Three different nanofiltration membranes were compared in filtering six pre-treated surface waters. The total organic carbon content of the feed waters varied from 2.0 to 4.2 mg l(-1). Other water quality parameters measured were conductivity, alkalinity, hardness, UV-absorbance, SUVA, E2/E3 value and molecular size distribution by high-performance size-exclusion chromatography. The natural organic matter removal efficiencies of the membranes were good and varied between 100% and 49%, and between 85% and 47% according to molecular size distribution and total organic carbon measurements, respectively. Removal of different molecular size fractions varied from 100% to 56%, 100% to 54% and 88% to 19%, regarding high molar mass, intermediate molar mass and low molar mass organic matter, respectively. The Desal-5 DL membrane produced the highest natural organic matter removals.

  17. Analysis of the Organic Matter in Interplanetary Dust Particles: Clues to the Organic Matter in Comets, Asteroids, and Interstellar Grains

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Keller, L. P.

    2003-01-01

    Reflection spectroscopy suggests the C- , P-, and D-types of asteroids contain abundant carbon, but these Vis-nearIR spectra are featureless, providing no information on the type(s) of carbonaceous matter. Infrared spectroscopy demonstrates that organic carbon is a significant component in comets and as grains or grain coatings in the interstellar medium. Most of the interplanetary dust particles (IDPs) recovered from the Earth s stratosphere are believed to be fragments from asteroids or comets, thus characterization of the carbon in IDPs provides the opportunity to determine the type(s) and abundance of organic matter in asteroids and comets. Some IDPs exhibit isotopic excesses of D and N-15, indicating the presence of interstellar material. The characterization of the carbon in these IDPs, and particularly any carbon spatially associated with the isotopic anomalies, provides the opportunity to characterize interstellar organic matter.

  18. The Case Against Charge Transfer Interactions in Dissolved Organic Matter Optical Properties

    NASA Astrophysics Data System (ADS)

    McKay, G.; Korak, J.; Erickson, P. R.; Latch, D. E.; McNeill, K.; Rosario-Ortiz, F.

    2017-12-01

    The optical properties of dissolved organic matter influence chemical and biological processes in all aquatic ecosystems. Organic matter optical properties have been used by scientists and engineers for decades for remote sensing, in situ monitoring, and characterizing laboratory samples to track dissolved organic carbon concentration and character. However, there is still a lack of understanding of the origin of organic matter optical properties, which could conflict with other empirical fluorescence interpretation methods (e.g. PARAFAC). Organic matter optical properties have been attributed to a charge-transfer model in which donor-acceptor complexes play a primary role. This model was evaluated by measuring the absorbance and fluorescence response of organic matter isolates to perturbations in solvent temperature, viscosity, and polarity, which affect the position and intensity of spectra for known donor-acceptor complexes of organic molecules. Absorbance and fluorescence spectral shape were unaffected by these perturbations, indicating that the distribution of absorbing and emitting species was unchanged. These results call into question the wide applicability of the charge-transfer model for explaining organic matter optical properties and suggest that future research should explore other models for organic matter photophysics.

  19. Influence of Multiple Environmental Factors on Organic Matter Chlorination in Podsol Soil.

    PubMed

    Svensson, Teresia; Montelius, Malin; Andersson, Malin; Lindberg, Cecilia; Reyier, Henrik; Rietz, Karolina; Danielsson, Åsa; Bastviken, David

    2017-12-19

    Natural chlorination of organic matter is common in soils. The abundance of chlorinated organic compounds frequently exceeds chloride in surface soils, and the ability to chlorinate soil organic matter (SOM) appears widespread among microorganisms. Yet, the environmental control of chlorination is unclear. Laboratory incubations with 36 Cl as a Cl tracer were performed to test how combinations of environmental factors, including levels of soil moisture, nitrate, chloride, and labile organic carbon, influenced chlorination of SOM from a boreal forest. Total chlorination was hampered by addition of nitrate or by nitrate in combination with water but enhanced by addition of chloride or most additions including labile organic matter (glucose and maltose). The greatest chlorination was observed after 15 days when nitrate and water were added together with labile organic matter. The effect that labile organic matter strongly stimulated the chlorination rates was confirmed by a second independent experiment showing higher stimulation at increased availability of labile organic matter. Our results highlight cause-effect links between chlorination and the studied environmental variables in podsol soil-with consistent stimulation by labile organic matter that did overrule the negative effects of nitrate.

  20. Mass Spectum Imaging of Organics Injected into Stardust Aerogel by Cometary Impacts

    NASA Technical Reports Server (NTRS)

    Clemett, S. J.; Nakamura-Messenger, K.; Messenger, S.

    2014-01-01

    Comets have largely escaped the hydrothermal processing that has affected the chemistry and mineralogy of even the most primitive meteorites. Consequently, they are expected to better preserve nebular and interstellar organic materials. Organic matter constitutes roughly 20-30% by weight of vol-atile and refractory cometary materials [1,2]. Yet organic matter identified in Stardust aerogel samples is only a minor component [3-5]. The dearth of intact organic matter, fine-grained and pre-solar materials led to suggestions that comet 81P/Wild-2 is com-posed largely of altered materials, and is more similar to meteorites than the primitive view of comets [6]. However, fine-grained materials are particularly susceptible to alteration and destruction during the hypervelocity impact. While hypervelocity capture can cause thermal pyrolysis of organic phases, some of the impacting organic component appears to have been explosively dispersed into surrounding aerogel [7]. We used a two-step laser mass spectrometer to map the distribution of organic matter within and sur-rounding a bulbous Stardust track to constrain the dispersion of organic matter during the impact.

  1. Interstellar chemistry recorded in organic matter from primitive meteorites.

    PubMed

    Busemann, Henner; Young, Andrea F; Alexander, Conel M O'd; Hoppe, Peter; Mukhopadhyay, Sujoy; Nittler, Larry R

    2006-05-05

    Organic matter in extraterrestrial materials has isotopic anomalies in hydrogen and nitrogen that suggest an origin in the presolar molecular cloud or perhaps in the protoplanetary disk. Interplanetary dust particles are generally regarded as the most primitive solar system matter available, in part because until recently they exhibited the most extreme isotope anomalies. However, we show that hydrogen and nitrogen isotopic compositions in carbonaceous chondrite organic matter reach and even exceed those found in interplanetary dust particles. Hence, both meteorites (originating from the asteroid belt) and interplanetary dust particles (possibly from comets) preserve primitive organics that were a component of the original building blocks of the solar system.

  2. Factors influencing the characteristics and distribution or surface organic matter in the Pacific-Atlantic connection

    NASA Astrophysics Data System (ADS)

    Barrera, Facundo; Lara, Rubén J.; Krock, Bernd; Garzón-Cardona, John Edison; Fabro, Elena; Koch, Boris P.

    2017-11-01

    The present work reports the first data set on particulate organic carbon (POC) and nitrogen (PON), and the high-resolution modelling of their stable isotope variability in the Patagonian Cold Estuarine System (PCES), with focus on particulate organic matter (POM) origin and distribution in dependence on physical, chemical and biological parameters. POC, PON, stable carbon (δ13C) and nitrogen isotopes (δ15N), dissolved organic nitrogen, phaeopigments, diatom, dinoflagellate and heterotrophic bacteria (HB) abundance are reported for 17 stations in different waters masses in the southern end of the Argentine shelf in late summer 2012. Most parameters denote clear differences between Beagle - Magellan Water (BMW), Subantarctic Shelf Water (SSW) and Subantarctic Water (SAW). POC and PON decreased from maxima in BMW to intermediate values in SSW and minima in SAW. There was a highly significant correlation among POC, PON and fluorescence indicators of diagenetic maturity of dissolved humic matter. This, together with the inverse correlations of salinity with POC and PON, and the wide range of C:N ratios indicate that POM in the study area is partly derived from terrestrial runoff, superimposed by autochthonous components from plankton of different life stages. HB abundance was significantly correlated with POC and dissolved organic matter (DOM), likely reflecting a resource control of HB and a significant contribution of bacterial biomass to POM in the nanoparticle fraction. The direct relationship between HB and dissolved humics suggests bacterial uptake of DOM fractions otherwise considered refractory. POM complexity was reflected in a wide variation of δ13C, despite the narrow temperature range of this region. The variability of stable isotopes of POC could be accounted for by a model with a degree of detail hitherto not reported in the literature. A multiple regression including C:N ratio, ammonium and the quotient between log abundance of diatoms

  3. Microbial Community Response to Terrestrially Derived Dissolved Organic Matter in the Coastal Arctic

    PubMed Central

    Sipler, Rachel E.; Kellogg, Colleen T. E.; Connelly, Tara L.; Roberts, Quinn N.; Yager, Patricia L.; Bronk, Deborah A.

    2017-01-01

    Warming at nearly twice the global rate, higher than average air temperatures are the new ‘normal’ for Arctic ecosystems. This rise in temperature has triggered hydrological and geochemical changes that increasingly release carbon-rich water into the coastal ocean via increased riverine discharge, coastal erosion, and the thawing of the semi-permanent permafrost ubiquitous in the region. To determine the biogeochemical impacts of terrestrially derived dissolved organic matter (tDOM) on marine ecosystems we compared the nutrient stocks and bacterial communities present under ice-covered and ice-free conditions, assessed the lability of Arctic tDOM to coastal microbial communities from the Chukchi Sea, and identified bacterial taxa that respond to rapid increases in tDOM. Once thought to be predominantly refractory, we found that ∼7% of dissolved organic carbon and ∼38% of dissolved organic nitrogen from tDOM was bioavailable to receiving marine microbial communities on short 4 – 6 day time scales. The addition of tDOM shifted bacterial community structure toward more copiotrophic taxa and away from more oligotrophic taxa. Although no single order was found to respond universally (positively or negatively) to the tDOM addition, this study identified 20 indicator species as possible sentinels for increased tDOM. These data suggest the true ecological impact of tDOM will be widespread across many bacterial taxa and that shifts in coastal microbial community composition should be anticipated. PMID:28649233

  4. Microbial Community Response to Terrestrially Derived Dissolved Organic Matter in the Coastal Arctic.

    PubMed

    Sipler, Rachel E; Kellogg, Colleen T E; Connelly, Tara L; Roberts, Quinn N; Yager, Patricia L; Bronk, Deborah A

    2017-01-01

    Warming at nearly twice the global rate, higher than average air temperatures are the new 'normal' for Arctic ecosystems. This rise in temperature has triggered hydrological and geochemical changes that increasingly release carbon-rich water into the coastal ocean via increased riverine discharge, coastal erosion, and the thawing of the semi-permanent permafrost ubiquitous in the region. To determine the biogeochemical impacts of terrestrially derived dissolved organic matter (tDOM) on marine ecosystems we compared the nutrient stocks and bacterial communities present under ice-covered and ice-free conditions, assessed the lability of Arctic tDOM to coastal microbial communities from the Chukchi Sea, and identified bacterial taxa that respond to rapid increases in tDOM. Once thought to be predominantly refractory, we found that ∼7% of dissolved organic carbon and ∼38% of dissolved organic nitrogen from tDOM was bioavailable to receiving marine microbial communities on short 4 - 6 day time scales. The addition of tDOM shifted bacterial community structure toward more copiotrophic taxa and away from more oligotrophic taxa. Although no single order was found to respond universally (positively or negatively) to the tDOM addition, this study identified 20 indicator species as possible sentinels for increased tDOM. These data suggest the true ecological impact of tDOM will be widespread across many bacterial taxa and that shifts in coastal microbial community composition should be anticipated.

  5. Do soils loose phosphorus with dissolved organic matter?

    NASA Astrophysics Data System (ADS)

    Kaiser, K.; Brödlin, D.; Hagedorn, F.

    2014-12-01

    During ecosystem development and soil formation, primary mineral sources of phosphorus are becoming increasingly depleted. Inorganic phosphorus forms tend to be bound strongly to or within secondary minerals, thus, are hardly available to plants and are not leached from soil. What about organic forms of phosphorus? Since rarely studied, little is known on the composition, mobility, and bioavailability of dissolved organic phosphorus. There is some evidence that plant-derived compounds, such as phytate, bind strongly to minerals as well, while microbial compounds, such as nucleotides and nucleic acids, may represent more mobile fractions of soil phosphorus. In some weakly developed, shallow soils, leaching losses of phosphorus seem to be governed by mobile organic forms. Consequently, much of the phosphorus losses observed during initial stages of ecosystem development may be due to the leaching of dissolved organic matter. However, the potentially mobile microbial compounds are enzymatically hydrolysable. Forest ecosystems on developed soils already depleted in easily available inorganic phosphorus are characterized by rapid recycling of organic phosphors. That can reduce the production of soluble forms of organic phosphorus as well as increase the enzymatic hydrolysis and subsequent plant uptake of phosphorus bound within dissolved organic matter. This work aims at giving an outlook to the potential role of dissolved organic matter in the cycling of phosphorus within developing forest ecosystems, based on literature evidence and first results of ongoing research.

  6. Anthropogenic aerosols as a source of ancient dissolved organic matter in glaciers

    USGS Publications Warehouse

    Stubbins, Aron; Hood, Eran; Raymond, Peter A.; Aiken, George R.; Sleighter, Rachel L.; Hernes, Peter J.; Butman, David; Hatcher, Patrick G.; Striegl, Robert G.; Schuster, Paul F.; Abdulla, Hussain A.N.; Vermilyea, Andrew W.; Scott, Durelle T.; Spencer, Robert G.M.

    2012-01-01

    Glacier-derived dissolved organic matter represents a quantitatively significant source of ancient, yet highly bioavailable carbon to downstream ecosystems. This finding runs counter to logical perceptions of age–reactivity relationships, in which the least reactive material withstands degradation the longest and is therefore the oldest. The remnants of ancient peatlands and forests overrun by glaciers have been invoked as the source of this organic matter. Here, we examine the radiocarbon age and chemical composition of dissolved organic matter in snow, glacier surface water, ice and glacier outflow samples from Alaska to determine the origin of the organic matter. Low levels of compounds derived from vascular plants indicate that the organic matter does not originate from forests or peatlands. Instead, we show that the organic matter on the surface of the glaciers is radiocarbon depleted, consistent with an anthropogenic aerosol source. Fluorescence spectrophotometry measurements reveal the presence of protein-like compounds of microbial or aerosol origin. In addition, ultrahigh-resolution mass spectrometry measurements document the presence of combustion products found in anthropogenic aerosols. Based on the presence of these compounds, we suggest that aerosols derived from fossil fuel burning are a source of pre-aged organic matter to glacier surfaces. Furthermore, we show that the molecular signature of the organic matter is conserved in snow, glacier water and outflow, suggesting that the anthropogenic carbon is exported relatively unchanged in glacier outflows.

  7. Organic geochemical analysis of sedimentary organic matter associated with uranium

    USGS Publications Warehouse

    Leventhal, J.S.; Daws, T.A.; Frye, J.S.

    1986-01-01

    Samples of sedimentary organic matter from several geologic environments and ages which are enriched in uranium (56 ppm to 12%) have been characterized. The three analytical techniqyes used to study the samples were Rock-Eval pyrolysis, pyrolysis-gas chromatography-mass spectrometry, and solid-state C-13 nuclear magnetic resonance (NMR) spectroscopy. In samples with low uranium content, the pyrolysis-gas chromatography products contain oxygenated functional groups (as hydroxyl) and molecules with both aliphatic and aromatic carbon atoms. These samples with low uranium content give measurable Rock-Eval hydrocarbon and organic-CO2 yields, and C-13 NMR values of > 30% aliphatic carbon. In contrast, uranium-rich samples have few hydrocarbon pyrolysis products, increased Rock-Eval organic-CO2 contents and > 70% aromatic carbon contents from C-13 NMR. The increase in aromaticity and decrease in hydrocarbon pyrolysis yield are related to the amount of uranium and the age of the uranium minerals, which correspond to the degree of radiation damage. The three analytical techniques give complementary results. Increase in Rock-Eval organic-CO2 yield correlates with uranium content for samples from the Grants uranium region. Calculations show that the amount of organic-CO2 corresponds to the quantity of uranium chemically reduced by the organic matter for the Grants uranium region samples. ?? 1986.

  8. Molecular Insights on Dissolved Organic Matter Transformation by Supraglacial Microbial Communities.

    PubMed

    Antony, Runa; Willoughby, Amanda S; Grannas, Amanda M; Catanzano, Victoria; Sleighter, Rachel L; Thamban, Meloth; Hatcher, Patrick G; Nair, Shanta

    2017-04-18

    Snow overlays the majority of Antarctica and is an important repository of dissolved organic matter (DOM). DOM transformations by supraglacial microbes are not well understood. We use ultrahigh resolution mass spectrometry to elucidate molecular changes in snowpack DOM by in situ microbial processes (up to 55 days) in a coastal Antarctic site. Both autochthonous and allochthonous DOM is highly bioavailable and is transformed by resident microbial communities through parallel processes of degradation and synthesis. DOM thought to be of a more refractory nature, such as dissolved black carbon and carboxylic-rich alicyclic molecules, was also rapidly and extensively reworked. Microbially reworked DOM exhibits an increase in the number and magnitude of N-, S-, and P-containing formulas, is less oxygenated, and more aromatic when compared to the initial DOM. Shifts in the heteroatom composition suggest that microbial processes may be important in the cycling of not only C, but other elements such as N, S, and P. Microbial reworking also produces photoreactive compounds, with potential implications for DOM photochemistry. Refined measurements of supraglacial DOM and their cycling by microbes is critical for improving our understanding of supraglacial DOM cycling and the biogeochemical and ecological impacts of DOM export to downstream environments.

  9. Characterization of organic matter in lake sediments from Minnesota and Yellowstone National Park

    USGS Publications Warehouse

    Dean, Walter E.

    2006-01-01

    Samples of sediment from lakes in Minnesota and Yellowstone National Park (YNP) were analyzed for organic carbon (OC), hydrogen richness by Rock-Eval pyrolysis, and stable carbon- and nitrogen-isotope composition of bulk organic matter. Values of delta 13C of lake plankton tend to be around -28 to -32 parts per thousand (0/00). Organic matter with values of delta 13C in the high negative 20s overlap with those of organic matter derived from C3 higher terrestrial plants but are at least 10 0/00 more depleted in 13C than organic matter derived from C4 terrestrial plants. If the organic matter is produced mainly by photosynthetic plankton and is not oxidized in the water column, there may be a negative correlation between H-richness (Rock-Eval pyrolysis H-index) and delta 13C, with more H-rich, algal organic matter having lower values of delta 13C. However, if aquatic organic matter is oxidized in the water column, or if the organic matter is a mixture of terrestrial and aquatic organic matter, then there may be no correlation between H-richness and carbon-isotopic composition. Values of delta 13C lower than about -28 0/00 probably indicate a contribution of bacterial biomass produced in the hypolimnion by chemoautotrophy or methanotrophy. In highly eutrophic lakes in which large amounts of 13C-depleted organic matter is continually removed from the epilimnion by photosynthesis throughout the growing season, the entire carbon reservoir in the epilimnion may become severely 13C-enriched so that 13C-enriched photosynthetic organic matter may overprint 13C-depleted chemosynthetic bacterial organic matter produced in the hypolimnon. Most processes involved with the nitrogen cycle in lakes, such as production of ammonia and nitrate, tend to produce 15N-enriched values of delta 15N. Most Minnesota lake sediments are 15N-enriched. However, some of the more OC-rich sediments have delta 15N values close to zero (delta 15N of air), suggesting that organic matter production is

  10. Evolution of Morphological and Physical Properties of Laboratory Interstellar Organic Residues with Ultraviolet Irradiation

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

    Piani, L.; Tachibana, S.; Endo, Y.

    Refractory organic compounds formed in molecular clouds are among the building blocks of the solar system objects and could be the precursors of organic matter found in primitive meteorites and cometary materials. However, little is known about the evolutionary pathways of molecular cloud organics from dense molecular clouds to planetary systems. In this study, we focus on the evolution of the morphological and viscoelastic properties of molecular cloud refractory organic matter. We found that the organic residue, experimentally synthesized at ∼10 K from UV-irradiated H{sub 2}O-CH{sub 3}OH-NH{sub 3} ice, changed significantly in terms of its nanometer- to micrometer-scale morphology andmore » viscoelastic properties after UV irradiation at room temperature. The dose of this irradiation was equivalent to that experienced after short residence in diffuse clouds (≤10{sup 4} years) or irradiation in outer protoplanetary disks. The irradiated organic residues became highly porous and more rigid and formed amorphous nanospherules. These nanospherules are morphologically similar to organic nanoglobules observed in the least-altered chondrites, chondritic porous interplanetary dust particles, and cometary samples, suggesting that irradiation of refractory organics could be a possible formation pathway for such nanoglobules. The storage modulus (elasticity) of photo-irradiated organic residues is ∼100 MPa irrespective of vibrational frequency, a value that is lower than the storage moduli of minerals and ice. Dust grains coated with such irradiated organics would therefore stick together efficiently, but growth to larger grains might be suppressed due to an increase in aggregate brittleness caused by the strong connections between grains.« less

  11. Organic matter variations in transgressive and regressive shales

    USGS Publications Warehouse

    Pasley, M.A.; Gregory, W.A.; Hart, G.F.

    1991-01-01

    Organic matter in the Upper Cretaceous Mancos Shale adjacent to the Tocito Sandstone in the San Juan Basin of New Mexico was characterized using organic petrology and organic geochemistry. Differences in the organic matter found in these regressive and transgressive offshore marine sediments have been documented and assessed within a sequence stratigraphic framework. The regressive Lower Mancos Shale below the Tocito Sandstone contains abundant well preserved phytoclasts and correspondingly low hydrogen indices. Total organic carbon values for the regressive shale are low. Sediments from the transgressive systems tract (Tocito Sandstone and overlying Upper Mancos Shale) contain less terrestrially derived organic matter, more amorphous non-structured protistoclasts, higher hydrogen indices and more total organic carbon. Advanced stages of degradation are characteristic of the phytoclasts found in the transgressive shale. Amorphous material in the transgressive shale fluoresces strongly while that found in the regressive shale is typically non-fluorescent. Data from pyrolysis-gas chromatography confirm these observations. These differences are apparently related to the contrasting depositional styles that were active on the shelf during regression and subsequent transgression. It is suggested that data from organic petrology and organic geochemistry provide greater resolution in sedimentologic and stratigraphic interpretations, particularly when working with basinward, fine-grained sediments. Petroleum source potential for the regressive Lower Mancos Shale below the Tocito Sandstone is poor. Based on abundant fluorescent amorphous material, high hydrogen indices, and high total organic carbon, the transgressive Upper Mancos Shale above the Tocito Sandstone possesses excellent source potential. This suggests that appreciable source potential can be found in offshore, fine-grained sediments of the transgressive systems tract below the condensed section and associated

  12. Particulate Organic Matter Composition in Stream Runoff Following Large Storms: Role of POM Sources, Particle Size, and Event Characteristics

    NASA Astrophysics Data System (ADS)

    Johnson, Erin R.; Inamdar, Shreeram; Kan, Jinjun; Vargas, Rodrigo

    2018-02-01

    Large storm events possess significant erosive energy capable of mobilizing large amounts of sediment and particulate organic matter (POM) into fluvial systems. This study investigated how stream POM composition varied as a function of the watershed POM source, particle size, storm event magnitude, and seasonal timing. POM composition was characterized for multiple watershed sources and for stream POM following storms in a second-order forested stream. Carbon (C) and nitrogen (N) amount, C:N ratio and isotopic content (13C and 15N) were determined for solid phase POM, whereas dissolved organic C, total N concentrations, and fluorescence characteristics were determined for solution/extracted POM. Key findings from this study were the following: (1) Composition of POM varied greatly with watershed sources with forest floor litter being C and N rich and labile, while stream banks and bed were C and N poor and recalcitrant. (2) Summer storms mobilized more carbon and nitrogen-rich labile sources, while winter events mobilized more carbon- and nitrogen-poor refractory material from near-stream sources. (3) POM composition varied by size class, with the coarse POM showing more C and N rich and labile properties, while the fine POM displayed more degraded and refractory properties. If climate variability increases the magnitude and intensity of large storm events, our observations suggest that this will not only increase the inputs of POM to aquatic systems but also result in the delivery of coarser, C and N rich, and more bioavailable POM to the stream drainage network.

  13. Quantifying the degradation of organic matter in marine sediments: A review and synthesis

    NASA Astrophysics Data System (ADS)

    Arndt, Sandra; Jørgensen, B. B.; LaRowe, D. E.; Middelburg, J. J.; Pancost, R. D.; Regnier, P.

    2013-08-01

    Quantifying the rates of biogeochemical processes in marine sediments is essential for understanding global element cycles and climate change. Because organic matter degradation is the engine behind benthic dynamics, deciphering the impact that various forces have on this process is central to determining the evolution of the Earth system. Therefore, recent developments in the quantitative modeling of organic matter degradation in marine sediments are critically reviewed. The first part of the review synthesizes the main chemical, biological and physical factors that control organic matter degradation in sediments while the second part provides a general review of the mathematical formulations used to model these processes and the third part evaluates their application over different spatial and temporal scales. Key transport mechanisms in sedimentary environments are summarized and the mathematical formulation of the organic matter degradation rate law is described in detail. The roles of enzyme kinetics, bioenergetics, temperature and biomass growth in particular are highlighted. Alternative model approaches that quantify the degradation rate constant are also critically compared. In the third part of the review, the capability of different model approaches to extrapolate organic matter degradation rates over a broad range of temporal and spatial scales is assessed. In addition, the structure, functions and parameterization of more than 250 published models of organic matter degradation in marine sediments are analyzed. The large range of published model parameters illustrates the complex nature of organic matter dynamics, and, thus, the limited transferability of these parameters from one site to another. Compiled model parameters do not reveal a statistically significant correlation with single environmental characteristics such as water depth, deposition rate or organic matter flux. The lack of a generic framework that allows for model parameters to be

  14. Spectral band selection for classification of soil organic matter content

    NASA Technical Reports Server (NTRS)

    Henderson, Tracey L.; Szilagyi, Andrea; Baumgardner, Marion F.; Chen, Chih-Chien Thomas; Landgrebe, David A.

    1989-01-01

    This paper describes the spectral-band-selection (SBS) algorithm of Chen and Landgrebe (1987, 1988, and 1989) and uses the algorithm to classify the organic matter content in the earth's surface soil. The effectiveness of the algorithm was evaluated comparing the results of classification of the soil organic matter using SBS bands with those obtained using Landsat MSS bands and TM bands, showing that the algorithm was successful in finding important spectral bands for classification of organic matter content. Using the calculated bands, the probabilities of correct classification for climate-stratified data were found to range from 0.910 to 0.980.

  15. Microbiological Insights of the Cycling of Chloroperoxidase-Reacted Organic Matter

    NASA Astrophysics Data System (ADS)

    Krzmarzick, M. J.; Boothe, M.; Lim, M. L.; Wang, X.; Brooks, M.

    2016-12-01

    Chloroperoxidase (CPO) enzymes from fungi are one mechanism in which organic matter is halogenated in terrestrial soils. In microcosm experiments, 17 groups of bacteria were found to substantially become enriched upon CPO-reacted organic matter amendment (CPO-OM). Though some enriched groups were organohalide-respiring bacteria, most were not related to any cultured isolates of bacteria and were either loosely linked to organohalide-degrading cultures or not at all. The large diversity of uncultured bacteria that is enriched from this substrate raises new questions regarding the pathways and mechanisms of the turnover of natural organochlorides. Upon changes in organic matter source material, salinity, temperature, and fermentable substrate, large changes in the CPO-OM enrichment culture occurred due to salinity, temperature, and fermentable substrate, though organic matter source material had a minimal effect. Thus, changes in geophysical conditions, not organic matter (pine forest vs oak forest), dominate the selection of bacteria implicated in the turnover of natural organochlorides. In related experiments, the CPO-OM enrichment culture expresses increased activity towards the dechlorination of chlorinated ethenes, indicating a direct connection between natural organochloride turnover and anthropogenic organochloride degradation and bioremediation, and could partly explain the heterogeneity of natural bioremediation potential at contaminated sites.

  16. Angiotensin II in Refractory Septic Shock.

    PubMed

    Antonucci, Elio; Gleeson, Patrick J; Annoni, Filippo; Agosta, Sara; Orlando, Sergio; Taccone, Fabio Silvio; Velissaris, Dimitrios; Scolletta, Sabino

    2017-05-01

    Refractory septic shock is defined as persistently low mean arterial blood pressure despite volume resuscitation and titrated vasopressors/inotropes in patients with a proven or suspected infection and concomitant organ dysfunction. Its management typically requires high doses of catecholamines, which can induce significant adverse effects such as ischemia and arrhythmias. Angiotensin II (Ang II), a key product of the renin-angiotensin-aldosterone system, is a vasopressor agent that could be used in conjunction with other vasopressors to stabilize critically ill patients during refractory septic shock, and reduce catecholamine requirements. However, very few clinical data are available to support Ang II administration in this setting. Here, we review the current literature on this topic to better understand the role of Ang II administration during refractory septic shock, differentiating experimental from clinical studies. We also consider the potential role of exogenous Ang II administration in specific organ dysfunction and possible pitfalls with Ang II in sepsis. Various issues remain unresolved and future studies should investigate important topics such as: the optimal dose and timing of Ang II administration, a comparison between Ang II and the other vasopressors (epinephrine; vasopressin), and Ang II effects on microcirculation.

  17. Composition and process for making an insulating refractory material

    DOEpatents

    Pearson, A.; Swansiger, T.G.

    1998-04-28

    A composition and process are disclosed for making an insulating refractory material. The composition includes calcined alumina powder, flash activated alumina powder, an organic polymeric binder and a liquid vehicle which is preferably water. Starch or modified starch may also be added. A preferred insulating refractory material made with the composition has a density of about 2.4--2.6 g/cm{sup 3} with reduced thermal conductivity, compared with tabular alumina. Of importance, the formulation has good abrasion resistance and crush strength during intermediate processing (commercial sintering) to attain full strength and refractoriness.

  18. Evolution of soil organic matter changes using pyrolysis and metabolic indices: a comparison between organic and mineral fertilization.

    PubMed

    Marinari, S; Masciandaro, G; Ceccanti, B; Grego, S

    2007-09-01

    The aim of this study was to evaluate chemical and biochemical changes of organic matter in fertilized (ammonium nitrate) and amended (vermicompost and manure) soils using pyrolysis and metabolic indices. The metabolic potential [dehydrogenase (DH-ase)/water soluble organic carbon (WSOC)], the metabolic quotient (qCO2) and the microbial quotient (Cmic:Corg) were calculated as indices of soil organic matter evolution. Pyrolysis-gas chromatography (Py-GC) was used to study structural changes in the organic matter. Carbon forms and microbial biomass have been measured by dichromate oxidation and fumigation-extraction methods, respectively. Dehydrogenase activity has been tested using INT (p-Iodonitrotetrazolium violet) as substrate. The results showed that organic amendment increased soil microbial biomass and its activity which were strictly related to pyrolytic mineralization and humification indices (N/O, B/E3). Mineral fertilization caused a greater alteration of native soil organic matter than the organic amendments, in that a high release of WSOC and relatively large amounts of aliphatic pyrolytic products, were observed. Therefore, the pyrolysis and metabolic indices provided similar and complementary information on soil organic matter changes after mineral and organic fertilization.

  19. Response of organic matter quality in permafrost soils to warming

    NASA Astrophysics Data System (ADS)

    Plaza, C.; Pegoraro, E.; Schuur, E.

    2016-12-01

    Global warming is predicted to thaw large quantities of the perennially frozen organic matter stored in northern permafrost soils. Upon thaw, this organic matter will be exposed to lateral export to water bodies and to microbial decomposition, which may exacerbate climate change by releasing significant amounts of greenhouse gases. To gain an insight into these processes, we investigated how the quality of permafrost soil organic matter responded to five years of warming. In particular, we sampled control and experimentally warmed soils in 2009 and 2013 from an experiment established in 2008 in a moist acidic tundra ecosystem in Healy, Alaska. We examined surface organic (0 to 15 cm), deep organic (15 to 35 cm), and mineral soil layers (35 to 55 cm) separately by means of stable isotope analysis (δ13C and δ15N) and solid-state 13C nuclear magnetic resonance. Compared to the control, the experimental warming did not affect the isotopic and molecular composition of soil organic matter across the depth profile. However, we did find significant changes with time. In particular, in the surface organic layer, δ13C decreased and alkyl/O-alkyl ratio increased from 2009 to 2013, which indicated variations in soil organic sources (e.g., changes in vegetation) and accelerated decomposition. In the deep organic layer, we found a slight increase in δ15N with time. In the mineral layer, δ13C values decreased slightly, whereas alkyl C/O-alkyl ratio increased, suggesting a preferential loss of relatively more degraded organic matter fractions probably by lateral transport by water flowing through the soil. Acknowledgements: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 654132. Web site: http://vulcan.comule.com

  20. A comparison of soil organic matter physical fractionation methods

    NASA Astrophysics Data System (ADS)

    Duddigan, Sarah; Alexander, Paul; Shaw, Liz; Collins, Chris

    2017-04-01

    Selecting a suitable physical fractionation to investigate soil organic matter dynamics from the plethora that are available is a difficult task. An initial investigation of four different physical fractionation methods was conducted (i) Six et al. (2002); (ii) Zimmermann et al. (2007); (iii) Sohi et al. (2001); and (iv) Plaza et al. (2013). Soils used for this were from a long-term organic matter field plot study where a sandy loam soil was subjected to the following treatments: Peat (Pt), Horse Manure (H), Garden Compost (GCf), Garden Compost at half rate (GCh), and a bare plot control (BP). Although each of these methods involved the isolation of unique fractions, in the interest of comparison, each fraction was categorised as either being (i) physically protected (i.e. in aggregates); (ii) chemically protected (such as in organo-mineral complexes); or (iii) unprotected by either of these mechanisms (so-called 'free' organic matter). Regardless of the fractionation method used, a large amount of the variation in total C contents of the different treated soils is accounted for by the differences in unprotected particulate organic matter. When comparing the methods to one another there were no consistent differences in carbon content in the physically protected, chemically protected, or unprotected fractions as operationally defined across all the five organic matter treatments. Therefore fractionation method selection, for this research, was primarily driven by the practicalities of conducting each method in the lab. All of the methods tested had their limitations, for use in this research. This is not a criticism of the methods themselves but largely a result of the lack of suitability for these particular samples. For example, samples that contain a lot of gravel can lead to problems for methods that use size distribution for fractionation. Problems can also be encountered when free particulate organic matter contributes a large proportion of the sample

  1. How does pyrogenic organic matter affect the N dynamic in agricultural soils? An incubation study

    NASA Astrophysics Data System (ADS)

    de La Rosa, José M.; Knicker, Heike

    2010-05-01

    Besides other environmental factors, N availability drives the carbon (C) and nitrogen (N) cycles in grasslands. Since grass-dominated ecosystems cover approximately 40% of the terrestrial surface and store more than 30% of global soil organic carbon (SOC), alterations to those ecosystems could have significant consequences and potential implications for global C and N cycles and climate (Schlesinger et al., 1990). Understanding the processes that govern the efficient cycling of nutrients through soil/plant systems remains an important topic to underpin the choice of strategies aimed at ensuring the long-term sustainability of ecosystems. In Mediterranean ecosystems, wild-fires occur frequently. Whereas factors such as water shortage or erosion contribute to reduced N-availability by lowering the litter input, burning additionally increase the refractory N and C-pools by charring litter and humic material (charred pyrogenic organic matter-PyOM) (Gonzalez-Pérez, 2004). In general, the addition of organic matter either as plant residues or farmyard manure has been shown to significantly increase biological activity, microbial biomass and enzyme activity in soil (Dick, 1992). Even in situations where microbial biomass appears to be unaffected, the activity of specific processes (e.g. N mineralization) can be significantly influenced by the addition of organic residues). However, little is known about the changes of the N cycle caused by the addition of PyOM. Therefore, the interest of our research was to study the impact of 15N enriched-biochars either alone or in conjunction with a 15N enriched fertilizer (K15NO3) on aggregate stability and organic carbon (C) and nitrogen (N) distribution among the different soil fractions. The latter may help to elucidate both, the quality of the stored organic matter and if the accumulation is related to interaction with the mineral matter. Therefore, biochar derived from grass material grown on 15N-enriched fertilizer was added

  2. Organic matter content of soil after logging of fir and redwood forests

    Treesearch

    Philip B. Durgin

    1980-01-01

    Organic matter in soil controls a variety of soil properties. A study in Humboldt County, California, evaluated changes in percentages of organic matter in soil as a function of time after timber harvest and soil depth in fir and redwood forests. To assess organic matter content, samples were taken from cutblocks of various ages in soil to depths of 1.33 m. Results...

  3. Soil Organic Matter Content Effects on Dermal Pesticide ...

    EPA Pesticide Factsheets

    Agricultural landscapes serve as active amphibian breeding grounds despite their seemingly poor habitat value. Activity of adults and dispersal of metamorphs to and from agricultural ponds occurs in most species from spring through late summer or early fall, a time that coincides with pesticide applications on farm fields and crops. In terrestrial landscapes, dermal contact with contaminated soil and plant matter may lead to bioconcentration as well as lethal and sublethal effects in amphibians.Although the physiological structure of the amphibian dermis may facilitate pesticide uptake, soil properties may ultimately dictate bioavailability of pesticides in terrestrial habitats. The organic matter fraction of soil readily binds to pesticides, potentially decreasing the availability of pesticides adhering to biological matter. Soil partition coefficient organic carbon content and soil-specific Koc values may be important to indicating pesticide bioavailability and potential bioconcentration in amphibians. Our study was designed to evaluate dermal uptake of five pesticide active ingredients on either high or low organic matter soils. We predicted that amphibian body burdens would be a function of soil carbon content or Koc. with greater bioconcentration in individuals exposed to pesticides on sa

  4. Bacterial biomarkers thermally released from dissolved organic matter

    USGS Publications Warehouse

    Greenwood, P.F.; Leenheer, J.A.; McIntyre, C.; Berwick, L.; Franzmann, P.D.

    2006-01-01

    Hopane biomarker products were detected using microscale sealed vessel (MSSV) pyrolysis gas chromatography-mass spectrometry (GC-MS) analysis of dissolved organic matter from natural aquatic systems colonised by bacterial populations. MSSV pyrolysis can reduce the polyhydroxylated alkyl side chain of bacteriohopanepolyols, yielding saturated hopane products which are more amenable to GC-MS detection than their functionalised precursors. This example demonstrates how the thermal conditions of MSSV pyrolysis can reduce the biologically-inherited structural functionality of naturally occurring organic matter such that additional structural fragments can be detected using GC methods. This approach complements traditional analytical pyrolysis methods by providing additional speciation information useful for establishing the structures and source inputs of recent or extant organic material. ?? 2006.

  5. Influence of dissolved organic carbon content on modelling natural organic matter acid-base properties.

    PubMed

    Garnier, Cédric; Mounier, Stéphane; Benaïm, Jean Yves

    2004-10-01

    Natural organic matter (NOM) behaviour towards proton is an important parameter to understand NOM fate in the environment. Moreover, it is necessary to determine NOM acid-base properties before investigating trace metals complexation by natural organic matter. This work focuses on the possibility to determine these acid-base properties by accurate and simple titrations, even at low organic matter concentrations. So, the experiments were conducted on concentrated and diluted solutions of extracted humic and fulvic acid from Laurentian River, on concentrated and diluted model solutions of well-known simple molecules (acetic and phenolic acids), and on natural samples from the Seine river (France) which are not pre-concentrated. Titration experiments were modelled by a 6 acidic-sites discrete model, except for the model solutions. The modelling software used, called PROSECE (Programme d'Optimisation et de SpEciation Chimique dans l'Environnement), has been developed in our laboratory, is based on the mass balance equilibrium resolution. The results obtained on extracted organic matter and model solutions point out a threshold value for a confident determination of the studied organic matter acid-base properties. They also show an aberrant decreasing carboxylic/phenolic ratio with increasing sample dilution. This shift is neither due to any conformational effect, since it is also observed on model solutions, nor to ionic strength variations which is controlled during all experiments. On the other hand, it could be the result of an electrode troubleshooting occurring at basic pH values, which effect is amplified at low total concentration of acidic sites. So, in our conditions, the limit for a correct modelling of NOM acid-base properties is defined as 0.04 meq of total analysed acidic sites concentration. As for the analysed natural samples, due to their high acidic sites content, it is possible to model their behaviour despite the low organic carbon concentration.

  6. THE INFLUENCE OF ORGANIC MATTER QUALITY ON THE TOXICITY AND PARTIONING OF SEDIMENT-ASSOCIATED FLUORANTHENE

    EPA Science Inventory

    Organic matter in sediment is derived from many sources, including dead plants and animals, fecal matter, and flocculated colloidal organic matter. hemical partitioning and toxicity of nonpolar organic contaminants is strongly affected by the quantity of sediment organic matter. ...

  7. Perchlorate-induced combustion of organic matter with variable molecular weights: Implications for Mars missions

    NASA Astrophysics Data System (ADS)

    Sephton, Mark A.; Lewis, James M. T.; Watson, Jonathan S.; Montgomery, Wren; Garnier, Carole

    2014-11-01

    Instruments on the Viking landers and Curiosity rover analyzed samples of Mars and detected carbon dioxide and organic compounds of uncertain origin. Mineral-assisted reactions are leading to uncertainty, particularly those involving perchlorate minerals which thermally decompose to produce chlorine and oxygen which can then react with organic matter to generate organochlorine compounds and carbon dioxide. Although generally considered a problem for interpretation, the release profiles of generated gases can indicate the type of organic matter present. We have performed a set of experiments with perchlorate and organic matter of variable molecular weights. Results indicate that organic susceptibility to thermal degradation and mineral-assisted reactions is related to molecular weight. Low molecular weight organic matter reacts at lower temperatures than its high molecular weight counterparts. The natural occurrence and association of organic matter with differing molecular weights helps to discriminate between contamination (usually low molecular weight organic matter only) and indigenous carbon (commonly low and high molecular weight organic matter together). Our results can be used to provide insights into data returning from Mars.

  8. Insights in groundwater organic matter from Liquid Chromatography-Organic Carbon Detection

    NASA Astrophysics Data System (ADS)

    Rutlidge, H.; Oudone, P.; McDonough, L.; Andersen, M. S.; Baker, A.; Meredith, K.; O'Carroll, D. M.

    2017-12-01

    Understanding the processes that control the concentration and characteristics of organic matter in groundwater has important implications for the terrestrial global carbon budget. Liquid Chromatography - Organic Carbon Detection (LC-OCD) is a size-exclusion based chromatography technique that separates the organic carbon into molecular weight size fractions of biopolymers, humic substances, building blocks (degradation products of humic substances), low molecular weight acids and low molecular weight neutrals. Groundwater and surface water samples were collected from a range of locations in Australia representing different surface soil, land cover, recharge type and hydrological properties. At one site hyporheic zone samples were also collected from beneath a stream. The results showed a general decrease in the aromaticity and molecular weight indices going from surface water, hyporheic downwelling and groundwater samples. The aquifer substrate also affected the organic composition. For example, groundwater samples collected from a zone of fractured rock showed a relative decrease in the proportion of humic substances, suggestive of sorption or degradation of humic substances. This work demonstrates the potential for using LC-OCD in elucidating the processes that control the concentration and characteristics of organic matter in groundwater.

  9. Abiotic Bromination of Soil Organic Matter

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

    Leri, Alessandra C.; Ravel, Bruce

    Biogeochemical transformations of plant-derived soil organic matter (SOM) involve complex abiotic and microbially mediated reactions. One such reaction is halogenation, which occurs naturally in the soil environment and has been associated with enzymatic activity of decomposer organisms. Building on a recent finding that naturally produced organobromine is ubiquitous in SOM, we hypothesized that inorganic bromide could be subject to abiotic oxidations resulting in bromination of SOM. Through lab-based degradation treatments of plant material and soil humus, we have shown that abiotic bromination of particulate organic matter occurs in the presence of a range of inorganic oxidants, including hydrogen peroxide andmore » assorted forms of ferric iron, producing both aliphatic and aromatic forms of organobromine. Bromination of oak and pine litter is limited primarily by bromide concentration. Fresh plant material is more susceptible to bromination than decayed litter and soil humus, due to a labile pool of mainly aliphatic compounds that break down during early stages of SOM formation. As the first evidence of abiotic bromination of particulate SOM, this study identifies a mechanistic source of the natural organobromine in humic substances and the soil organic horizon. Formation of organobromine through oxidative treatments of plant material also provides insights into the relative stability of aromatic and aliphatic components of SOM.« less

  10. Abiotic Bromination of Soil Organic Matter.

    PubMed

    Leri, Alessandra C; Ravel, Bruce

    2015-11-17

    Biogeochemical transformations of plant-derived soil organic matter (SOM) involve complex abiotic and microbially mediated reactions. One such reaction is halogenation, which occurs naturally in the soil environment and has been associated with enzymatic activity of decomposer organisms. Building on a recent finding that naturally produced organobromine is ubiquitous in SOM, we hypothesized that inorganic bromide could be subject to abiotic oxidations resulting in bromination of SOM. Through lab-based degradation treatments of plant material and soil humus, we have shown that abiotic bromination of particulate organic matter occurs in the presence of a range of inorganic oxidants, including hydrogen peroxide and assorted forms of ferric iron, producing both aliphatic and aromatic forms of organobromine. Bromination of oak and pine litter is limited primarily by bromide concentration. Fresh plant material is more susceptible to bromination than decayed litter and soil humus, due to a labile pool of mainly aliphatic compounds that break down during early stages of SOM formation. As the first evidence of abiotic bromination of particulate SOM, this study identifies a mechanistic source of the natural organobromine in humic substances and the soil organic horizon. Formation of organobromine through oxidative treatments of plant material also provides insights into the relative stability of aromatic and aliphatic components of SOM.

  11. Organic matter controls of iron incorporation in growing sea ice

    NASA Astrophysics Data System (ADS)

    Janssens, Julie; Meiners, Klaus M.; Townsend, Ashley T.; Lannuzel, Delphine

    2018-03-01

    This study presents the first laboratory-controlled sea-ice growth experiment conducted under trace metal clean conditions. The role played by organic matter, in the incorporation of iron (Fe) into sea ice was investigated by means of laboratory ice-growth experiments using a titanium cold-finger apparatus. Experiments were also conducted to understand the role of extracellular polymeric substances (EPS) in the enrichment of ammonium in sea ice. Sea ice was grown from several seawater solutions containing different quantities and qualities of particulate Fe (PFe), dissolved Fe (DFe) and organic matter. Sea ice and seawater were analyzed for particulate organic carbon and nitrogen, macro-nutrients, extracellular EPS, PFe and DFe, and particulate aluminium. The experiments showed that biogenic PFe is preferentially incorporated into sea ice compared to lithogenic PFe. Furthermore, sea ice grown from ultra-violet (UV) and non-UV treated seawaters exhibits contrasting incorporation rates of organic matter and Fe. Whereas the effects of UV-treatments were not always significant, we do find indications that the type or organic matter controls the enrichment of Fe in forming sea ice.. Specifically, we come to the conclusion that the incorporation of DFe is favored by the presence of organic ligands in the source solution.

  12. Correlated microanalysis of cometary organic grains returned by Stardust

    NASA Astrophysics Data System (ADS)

    de Gregorio, Bradley T.; Stroud, Rhonda M.; Cody, George D.; Nittler, Larry R.; David Kilcoyne, A. L.; Wirick, Sue

    2011-09-01

    Abstract- Carbonaceous matter in Stardust samples returned from comet 81P/Wild 2 is observed to contain a wide variety of organic functional chemistry. However, some of this chemical variety may be due to contamination or alteration during particle capture in aerogel. We investigated six carbonaceous Stardust samples that had been previously analyzed and six new samples from Stardust Track 80 using correlated transmission electron microscopy (TEM), X-ray absorption near-edge structure spectroscopy (XANES), and secondary ion mass spectroscopy (SIMS). TEM revealed that samples from Track 35 containing abundant aliphatic XANES signatures were predominantly composed of cometary organic matter infilling densified silica aerogel. Aliphatic organic matter from Track 16 was also observed to be soluble in the epoxy embedding medium. The nitrogen-rich samples in this study (from Track 22 and Track 80) both contained metal oxide nanoparticles, and are likely contaminants. Only two types of cometary organic matter appear to be relatively unaltered during particle capture. These are (1) polyaromatic carbonyl-containing organic matter, similar to that observed in insoluble organic matter (IOM) from primitive meteorites, interplanetary dust particles (IDPs), and in other carbonaceous Stardust samples, and (2) highly aromatic refractory organic matter, which primarily constitutes nanoglobule-like features. Anomalous isotopic compositions in some of these samples also confirm their cometary heritage. There also appears to be a significant labile aliphatic component of Wild 2 organic matter, but this material could not be clearly distinguished from carbonaceous contaminants known to be present in the Stardust aerogel collector.

  13. Soil Water Content Sensor Response to Organic Matter Content under Laboratory Conditions

    PubMed Central

    Fares, Ali; Awal, Ripendra; Bayabil, Haimanote K.

    2016-01-01

    Studies show that the performance of soil water content monitoring (SWCM) sensors is affected by soil physical and chemical properties. However, the effect of organic matter on SWCM sensor responses remains less understood. Therefore, the objectives of this study are to (i) assess the effect of organic matter on the accuracy and precision of SWCM sensors using a commercially available soil water content monitoring sensor; and (ii) account for the organic matter effect on the sensor’s accuracy. Sand columns with seven rates of oven-dried sawdust (2%, 4%, 6%, 8%, 10%, 12% and 18% v/v, used as an organic matter amendment), thoroughly mixed with quartz sand, and a control without sawdust were prepared by packing quartz sand in two-liter glass containers. Sand was purposely chosen because of the absence of any organic matter or salinity, and also because sand has a relatively low cation exchange capacity that will not interfere with the treatment effect of the current work. Sensor readings (raw counts) were monitored at seven water content levels (0, 0.02, 0.04, 0.08, 0.12, 0.18, 0.24, and 0.30 cm3 cm−3) by uniformly adding the corresponding volumes of deionized water in addition to the oven-dry one. Sensor readings were significantly (p < 0.05) affected by the organic matter level and water content. Sensor readings were strongly correlated with the organic matter level (R2 = 0.92). In addition, the default calibration equation underestimated the water content readings at the lower water content range (<0.05 cm3 cm−3), while it overestimated the water content at the higher water content range (>0.05 cm3 cm−3). A new polynomial calibration equation that uses raw count and organic matter content as covariates improved the accuracy of the sensor (RMSE = 0.01 cm3 cm−3). Overall, findings of this study highlight the need to account for the effect of soil organic matter content to improve the accuracy and precision of the tested sensor under different soils and

  14. Soil Water Content Sensor Response to Organic Matter Content under Laboratory Conditions.

    PubMed

    Fares, Ali; Awal, Ripendra; Bayabil, Haimanote K

    2016-08-05

    Studies show that the performance of soil water content monitoring (SWCM) sensors is affected by soil physical and chemical properties. However, the effect of organic matter on SWCM sensor responses remains less understood. Therefore, the objectives of this study are to (i) assess the effect of organic matter on the accuracy and precision of SWCM sensors using a commercially available soil water content monitoring sensor; and (ii) account for the organic matter effect on the sensor's accuracy. Sand columns with seven rates of oven-dried sawdust (2%, 4%, 6%, 8%, 10%, 12% and 18% v/v, used as an organic matter amendment), thoroughly mixed with quartz sand, and a control without sawdust were prepared by packing quartz sand in two-liter glass containers. Sand was purposely chosen because of the absence of any organic matter or salinity, and also because sand has a relatively low cation exchange capacity that will not interfere with the treatment effect of the current work. Sensor readings (raw counts) were monitored at seven water content levels (0, 0.02, 0.04, 0.08, 0.12, 0.18, 0.24, and 0.30 cm³ cm(-3)) by uniformly adding the corresponding volumes of deionized water in addition to the oven-dry one. Sensor readings were significantly (p < 0.05) affected by the organic matter level and water content. Sensor readings were strongly correlated with the organic matter level (R² = 0.92). In addition, the default calibration equation underestimated the water content readings at the lower water content range (<0.05 cm³ cm(-3)), while it overestimated the water content at the higher water content range (>0.05 cm³ cm(-3)). A new polynomial calibration equation that uses raw count and organic matter content as covariates improved the accuracy of the sensor (RMSE = 0.01 cm³ cm(-3)). Overall, findings of this study highlight the need to account for the effect of soil organic matter content to improve the accuracy and precision of the tested sensor under different soils and

  15. Phenanthrene sorption with heterogeneous organic matter in a landfill aquifer material

    USGS Publications Warehouse

    Karapanagioti, H.K.; Sabatini, D.A.; Kleineidam, S.; Grathwohl, P.; Ligouis, B.

    1999-01-01

    Phenanthrene was used as a model chemical to study the sorption properties of Canadian River Alluvium aquifer material. Both equilibrium and kinetic sorption processes were evaluated through batch studies. The bulk sample was divided into subsamples with varying properties such as particle size, organic content, equilibration time, etc. in order to determine the effect of these properties on resulting sorption parameters. The data have been interpreted and the effect of experimental variables was quantified using the Freundlich isotherm model and a numerical solution of Fick's 2nd law in porous media. Microscopic organic matter characterization proved to be a valuable tool for explaining the results. Different organic matter properties and sorption mechanisms were observed for each soil subsample. Samples containing coal particles presented high Koc values. Samples with organic matter dominated by organic coatings on quartz grains presented low Koc values and contained a high percentage of fast sorption sites. The numerical solution of Fick's 2ndlaw requires the addition of two terms (fast and slow) in order to fit the kinetics of these heterogeneous samples properly. These results thus demonstrate the need for soil organic matter characterization in order to predict and explain the sorption properties of a soil sample containing heterogeneous organic matter and also the difficulty and complexity of modeling sorption in such samples.

  16. Insights into the nature of cometary organic matter from terrestrial analogues

    NASA Astrophysics Data System (ADS)

    Court, Richard W.; Sephton, Mark A.

    2012-04-01

    The nature of cometary organic matter is of great interest to investigations involving the formation and distribution of organic matter relevant to the origin of life. We have used pyrolysis-Fourier transform infrared (FTIR) spectroscopy to investigate the chemical effects of the irradiation of naturally occurring bitumens, and to relate their products of pyrolysis to their parent assemblages. The information acquired has then been applied to the complex organic matter present in cometary nuclei and comae. Amalgamating the FTIR data presented here with data from published studies enables the inference of other comprehensive trends within hydrocarbon mixtures as they are progressively irradiated in a cometary environment, namely the polymerization of lower molecular weight compounds; an increased abundance of polycyclic aromatic hydrocarbon structures; enrichment in 13C; reduction in atomic H/C ratio; elevation of atomic O/C ratio and increase in the temperature required for thermal degradation. The dark carbonaceous surface of a cometary nucleus will display extreme levels of these features, relative to the nucleus interior, while material in the coma will reflect the degree of irradiation experienced by its source location in the nucleus. Cometary comae with high methane/water ratios indicate a nucleus enriched in methane, favouring the formation of complex organic matter via radiation-induced polymerization of simple precursors. In contrast, production of complex organic matter is hindered in a nucleus possessing a low methane/water ration, with the complex organic matter that does form possessing more oxygen-containing species, such as alcohol, carbonyl and carboxylic acid functional groups, resulting from reactions with hydroxyl radicals formed by the radiolysis of the more abundant water. These insights into the properties of complex cometary organic matter should be of particular interest to both remote observation and space missions involving in situ

  17. Soil Organic Matter (SOM): Molecular Simulations

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

    Andersen, Amity

    Molecular simulation is a powerful tool used to gain an atomistic, molecular, and nanoscale level understanding of the structure, dynamics, and interactions from adsorption on minerals and assembly in aggregates of soil organic matter (SOM). Given the importance of SOM fate and persistence in soils and the current knowledge gaps, applications of atomistic scale simulations to study the complex compounds in SOM and their interactions in self-assembled aggregates composed of different organic matter compounds and with mineral surfaces of different types common in soils are few and far between. Here, we describe various molecular simulation methods that are currently inmore » use in various areas and applicable to SOM research, followed by a brief survey of specific applications to SOM research and an illustration with our own recent efforts in this area. We conclude with an outlook and the challenges for future research in this area.« less

  18. Composition and process for making an insulating refractory material

    DOEpatents

    Pearson, Alan; Swansiger, Thomas G.

    1998-04-28

    A composition and process for making an insulating refractory material. The composition includes calcined alumina powder, flash activated alumina powder, an organic polymeric binder and a liquid vehicle which is preferably water. Starch or modified starch may also be added. A preferred insulating refractory material made with the composition has a density of about 2.4-2.6 g/cm.sup.3 with reduced thermal conductivity, compared with tabular alumina. Of importance, the formulation has good abrasion resistance and crush strength during intermediate processing (commercial sintering) to attain full strength and refractoriness, good abrasion resistance and crush strength.

  19. Pre-biotic organic matter from comets and asteroids

    NASA Technical Reports Server (NTRS)

    Anders, Edward

    1989-01-01

    Only meteoritic fragments small enough to be gently decelerated by the atmosphere (10 to the -12th g to 10 to the -6th g) can deliver organic matter intact. The amount of such 'soft-landed' organic carbon can be estimated from data for the infall rate of meteoritic matter. At present rates, only about 0.0006 g/sq cm intact organic carbon would accumulate in 100 million years, but at the higher rates of about four billion yr ago, about 20 g/sq cm may have accumulated in the few hundred million years between the last cataclysmic impact and the beginning of life. It may have included some biologically important compounds that did not form by abiotic synthesis on earth.

  20. Mapping forest soil organic matter on New Jersey's coastal plain

    Treesearch

    Brian J. Clough; Edwin J. Green; Richard B. Lathrop

    2012-01-01

    Managing forest soil organic matter (SOM) stocks is a vital strategy for reducing the impact of anthropogenic carbon dioxide emissions. However, the SOM pool is highly variable, and developing accurate estimates to guide management decisions has remained a difficult task. We present the results of a spatial model designed to map soil organic matter for all forested...

  1. Spent refractory reuse

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

    Bennett, J.P.; Kwong, K.S.; Clark, J.A.

    1996-12-31

    The Albany Research Center is conducting work on spent refractory recycling/alternate use, including a review of refractory usage and current recycling/disposal practices. Research has focused on the hazardous nature of some spent refractory materials, with emphasis on lead pickup. Information on the issues associated with the reuse of spent refractories will be presented, including those associated with hazardous materials.

  2. Sub-micrometer refractory carbonaceous particles in the polar stratosphere

    NASA Astrophysics Data System (ADS)

    Schütze, Katharina; Wilson, James Charles; Weinbruch, Stephan; Benker, Nathalie; Ebert, Martin; Günther, Gebhard; Weigel, Ralf; Borrmann, Stephan

    2017-10-01

    , aircraft exhaust, volcanic emissions and biomass burning can certainly be excluded as sources. The same is true for the less probable but globally important sources: wood burning, coal burning, diesel engines and ship emissions. Recondensed organic matter and extraterrestrial particles, potentially originating from ablation and fragmentation, remain as possible sources of the refractory carbonaceous particles studied. However, additional work is required in order to identify the sources unequivocally.

  3. Effects of ozonation pretreatment on natural organic matter and wastewater derived organic matter - Possible implications on the formation of ozonation by-products.

    PubMed

    Papageorgiou, Alexandros; Stylianou, Stylianos K; Kaffes, Pavlos; Zouboulis, Anastasios I; Voutsa, Dimitra

    2017-03-01

    The aim of this study was to investigate possible implications of natural and wastewater derived organic matter in river water that is subsequently used following treatment for drinking purposes. River water was subjected to lab-scale ozonation experiments under different ozone doses (0.1, 0.4, 0.8, 1.0 and 2.0 mgO 3 /mgC) and contact times (1, 3, 5, 8 and 10 min). Mixtures of river water with humic acids or wastewaters (sewage wastewater and secondary effluents) at different proportions were also ozonated. Dissolved organic carbon and biodegradable dissolved organic carbon concentrations as well as spectroscopic characteristics (UV absorbance and fluorescence intensities) of different types of dissolved organic matter and possible changes due to the ozonation treatment are presented. River water, humic substances and wastewater exhibited distinct spectroscopic characteristics that could serve for pollution source tracing. Wastewater impacted surface water results in higher formation of carbonyl compounds. However, the formation yield (μg/mgC) of wastewaters was lower than that of surface water possibly due to different composition of wastewater derived organic matter and the presence of scavengers, which may limit the oxidative efficiency of ozone. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Refractory rheumatoid vasculitis

    PubMed Central

    Kumar, Ashok; Goel, Anshul; Lapsiwala, Mehul; Singhal, Suman

    2016-01-01

    Systemic rheumatoid vasculitis (SRV) can develop in rheumatoid arthritis of long duration and high disease activity. It most commonly manifests as cutaneous vasculitis and mononeuritis multiplex. This can involve any organ of the body and carries very high mortality. We report a case of a young male who had rheumatoid arthritis for the past 15 years and became refractory to standard drugs and anti-TNF agents. He subsequently developed SRV, which started as mononeuritis multiplex. Disease progressed to result in gangrene of hands and feet despite receiving intravenous cyclophosphamide. Intravenous immunoglobulin and rituximab also could not provide any response. Prolonged ICU stay resulted in critical care neuromyopathy. Central nervous system vasculitis developed even after repeated infusions of intravenous immunoglobulins and at last he died of complications. In this case report, we have presented rare and chronic protracted presentation of rheumatoid vasculitis involving skin, nerves, brain and testis, which was refractory to the recommended therapies. PMID:28031844

  5. Interstellar and Solar System Organic Matter Preserved in Interplanetary Dust

    NASA Technical Reports Server (NTRS)

    Messenger, Scott; Nakamura-Messenger, Keiko

    2015-01-01

    Interplanetary dust particles (IDPs) collected in the Earth's stratosphere derive from collisions among asteroids and by the disruption and outgassing of short-period comets. Chondritic porous (CP) IDPs are among the most primitive Solar System materials. CP-IDPs have been linked to cometary parent bodies by their mineralogy, textures, C-content, and dynamical histories. CP-IDPs are fragile, fine-grained (less than um) assemblages of anhydrous amorphous and crystalline silicates, oxides and sulfides bound together by abundant carbonaceous material. Ancient silicate, oxide, and SiC stardust grains exhibiting highly anomalous isotopic compositions are abundant in CP-IDPs, constituting 0.01 - 1 % of the mass of the particles. The organic matter in CP-IDPs is isotopically anomalous, with enrichments in D/H reaching 50x the terrestrial SMOW value and 15N/14N ratios up to 3x terrestrial standard compositions. These anomalies are indicative of low T (10-100 K) mass fractionation in cold molecular cloud or the outermost reaches of the protosolar disk. The organic matter shows distinct morphologies, including sub-um globules, bubbly textures, featureless, and with mineral inclusions. Infrared spectroscopy and mass spectrometry studies of organic matter in IDPs reveals diverse species including aliphatic and aromatic compounds. The organic matter with the highest isotopic anomalies appears to be richer in aliphatic compounds. These materials also bear similarities and differences with primitive, isotopically anomalous organic matter in carbonaceous chondrite meteorites. The diversity of the organic chemistry, morphology, and isotopic properties in IDPs and meteorites reflects variable preservation of interstellar/primordial components and Solar System processing. One unifying feature is the presence of sub-um isotopically anomalous organic globules among all primitive materials, including IDPs, meteorites, and comet Wild-2 samples returned by the Stardust mission.

  6. Caracterisation of anthropogenic contribution to the coastal fluorescent organic matter

    NASA Astrophysics Data System (ADS)

    El Nahhal, Ibrahim; Nouhi, Ayoub; Mounier, Stéphane

    2015-04-01

    It is known that most of the coastal fluorescent organic matter is of a terrestrial origin (Parlanti, 2000; Tedetti, Guigue, & Goutx, 2010). However, the contribution of the anthropogenic organic matter to this pool is not well defined and evaluated. In this work the monitoring of little bay (Toulon Bay, France) was done in the way to determine the organic fluorescent response during a winter period. The sampling campaign consisted of different days during the month of December, 2014 ( 12th, 15th, 17th, 19th) on 21 different sampling sites for the fluorescence measurements (without any filtering of the samples) and the whole month of December for the bacterial and the turbidity measurements. Excitation Emission Matrices (EEMs) of fluorescence (from 200 to 400 nm and 220 to 420 nm excitation and emission range) were treated by parallel factor analysis (PARAFAC).The parafac analysis of the EEM datasets was conducted using PROGMEEF software in Matlab langage. On the same time that the turbidity and bacterial measurement (particularly the E.Coli concentration) were determined. The results gives in a short time range, information on the the contribution of the anthropogenic inputs to the coastal fluorescent organic matter. In addition, the effect of salinity on the photochemical degradation of the anthropogenic organic matter (especially those from wastewater treatment plants) will be studied to investigate their fate in the water end member by the way of laboratory experiments. Parlanti, E. (2000). Dissolved organic matter fluorescence spectroscopy as a tool to estimate biological activity in a coastal zone submitted to anthropogenic inputs. Organic Geochemistry, 31(12), 1765-1781. doi:10.1016/S0146-6380(00)00124-8 Tedetti, M., Guigue, C., & Goutx, M. (2010). Utilization of a submersible UV fluorometer for monitoring anthropogenic inputs in the Mediterranean coastal waters. Marine Pollution Bulletin, 60(3), 350-62. doi:10.1016/j.marpolbul.2009.10.018

  7. Production of Dissolved Organic Matter During Doliolid Feeding

    NASA Astrophysics Data System (ADS)

    Castellane, N. J.; Paffenhofer, G. A.; Stubbins, A.

    2016-02-01

    The biological carbon pump (BCP) draws carbon dioxide out of the atmosphere and buries it at the seafloor. The efficiency of the BCP is determined in part by the sinking rates of particulate organic carbon (POC) from ocean surface waters. Zooplankton can package POC into fecal pellets with higher sinking rates than their food source (e.g. phytoplankton), increasing the efficiency of the BCP. However, dissolved organic carbon (DOC) is also produced as zooplankton ingest and egest food, reducing the efficiency of BCP. The pelagic tunicate Dolioletta gegenbauri (doliolid) is a gelatinous zooplankton found at high concentrations in shelf waters, including our study site: the South Atlantic Bight. Doliolids are efficient grazers capable of stripping large quantities of phytoplankton from the water column. To determine the balance between pellet formation and DOC production during feeding, doliolids (6-7 mm gonozooids) were placed in natural seawater amended with a live phytoplankton food source and incubated on a plankton wheel. Dissolved organic matter (DOM) released directly to the water as well as the water soluble fraction of pellet organic matter were quantified and optically characterized. Colored dissolved organic matter (CDOM) absorbance and fluorescence spectra revealed that doliolid feeding produces DOM with optical properties that are commonly indicative of newly produced, highly biolabile DOM of microbial origin. Based upon these optical characteristics, doliolid-produced DOM is expected to be highly bio-labile in the environment and therefore rapidly degraded by surface ocean microbes shunting phytoplankton-derived organic carbon out of the BCP and back to dissolved inorganic carbon.

  8. Temperature response of litter and soil organic matter decomposition is determined by chemical composition of organic material.

    PubMed

    Erhagen, Björn; Öquist, Mats; Sparrman, Tobias; Haei, Mahsa; Ilstedt, Ulrik; Hedenström, Mattias; Schleucher, Jürgen; Nilsson, Mats B

    2013-12-01

    The global soil carbon pool is approximately three times larger than the contemporary atmospheric pool, therefore even minor changes to its integrity may have major implications for atmospheric CO2 concentrations. While theory predicts that the chemical composition of organic matter should constitute a master control on the temperature response of its decomposition, this relationship has not yet been fully demonstrated. We used laboratory incubations of forest soil organic matter (SOM) and fresh litter material together with NMR spectroscopy to make this connection between organic chemical composition and temperature sensitivity of decomposition. Temperature response of decomposition in both fresh litter and SOM was directly related to the chemical composition of the constituent organic matter, explaining 90% and 70% of the variance in Q10 in litter and SOM, respectively. The Q10 of litter decreased with increasing proportions of aromatic and O-aromatic compounds, and increased with increased contents of alkyl- and O-alkyl carbons. In contrast, in SOM, decomposition was affected only by carbonyl compounds. To reveal why a certain group of organic chemical compounds affected the temperature sensitivity of organic matter decomposition in litter and SOM, a more detailed characterization of the (13) C aromatic region using Heteronuclear Single Quantum Coherence (HSQC) was conducted. The results revealed considerable differences in the aromatic region between litter and SOM. This suggests that the correlation between chemical composition of organic matter and the temperature response of decomposition differed between litter and SOM. The temperature response of soil decomposition processes can thus be described by the chemical composition of its constituent organic matter, this paves the way for improved ecosystem modeling of biosphere feedbacks under a changing climate. © 2013 John Wiley & Sons Ltd.

  9. Mapping Soil Organic Matter with Hyperspectral Imaging

    NASA Astrophysics Data System (ADS)

    Moni, Christophe; Burud, Ingunn; Flø, Andreas; Rasse, Daniel

    2014-05-01

    Soil organic matter (SOM) plays a central role for both food security and the global environment. Soil organic matter is the 'glue' that binds soil particles together, leading to positive effects on soil water and nutrient availability for plant growth and helping to counteract the effects of erosion, runoff, compaction and crusting. Hyperspectral measurements of samples of soil profiles have been conducted with the aim of mapping soil organic matter on a macroscopic scale (millimeters and centimeters). Two soil profiles have been selected from the same experimental site, one from a plot amended with biochar and another one from a control plot, with the specific objective to quantify and map the distribution of biochar in the amended profile. The soil profiles were of size (30 x 10 x 10) cm3 and were scanned with two pushbroomtype hyperspectral cameras, one which is sensitive in the visible wavelength region (400 - 1000 nm) and one in the near infrared region (1000 - 2500 nm). The images from the two detectors were merged together into one full dataset covering the whole wavelength region. Layers of 15 mm were removed from the 10 cm high sample such that a total of 7 hyperspectral images were obtained from the samples. Each layer was analyzed with multivariate statistical techniques in order to map the different components in the soil profile. Moreover, a 3-dimensional visalization of the components through the depth of the sample was also obtained by combining the hyperspectral images from all the layers. Mid-infrared spectroscopy of selected samples of the measured soil profiles was conducted in order to correlate the chemical constituents with the hyperspectral results. The results show that hyperspectral imaging is a fast, non-destructive technique, well suited to characterize soil profiles on a macroscopic scale and hence to map elements and different organic matter quality present in a complete pedon. As such, we were able to map and quantify biochar in our

  10. Effect of mismanagement at the state of organic matter in soil

    NASA Astrophysics Data System (ADS)

    Hladký, Jan; Elbl, Jakub; Kynický, Jindřich; Dvořáčková, Helena; Juřička, David; Pecina, Václav; Brtnický, Martin

    2017-04-01

    Organic matter is an essential part of the soil. It affects the physical, chemical, and biological properties of the soil. It is therefore necessary to maintain organic matter in the soil and its quality as the prevention of soil degradation. Loss of organic matter is in the Czech Republic threatened up to 45% of arable soil. The most important reason for the loss of organic matter in the soil is poor management, especially improper crop rotation, cultivation of erosion-prone crops where erosion takes away valuable topsoil with nutrients and organic matter. The aim of our study was to verify the influence of inappropriate management on selected 5 plots in southern Moravia in the Czech Republic. It is the region with the highest incidence of water erosion in the Czech Republic. Were selected plots with significantly sloping, where corn was grown. Samples were taken in the autumn after the harvest, each of topsoil. The sampling sites were placed in positions on the slope where soil was not damaged by erosion, as well as the place greatest damage and the place where washed soil was accumulated. Soil average humus content was for undamaged position on the slope 1.93% and 0.84 quality, the most heavily damaged part of the slope humus content dropped to 1.35% and its quality at only 0.56. In the case of position of accumulated soils was found the average amount of humus 1.70% and 0.90 quality. Humus content and its quality is statistically significantly influenced by water erosion (α = 0.05). The study showed that bad management, when there is not crop rotation adapted to the given conditions and not subjected to any suitable soil-protecting technologies, there is significant damage to soils, which shows mainly organic matter decline and a decline in its quality. Continuation of our study will verify the possibility of stabilization of soil organic matter and draft appropriate technologies.

  11. Temperature sensitivity of organic-matter decay in tidal marshes

    USGS Publications Warehouse

    Kirwan, Matthew L.; Guntenspergen, Glenn R.; Langley, J.A.

    2014-01-01

    Approximately half of marine carbon sequestration takes place in coastal wetlands, including tidal marshes, where organic matter contributes to soil elevation and ecosystem persistence in the face of sea-level rise. The long-term viability of marshes and their carbon pools depends, in part, on how the balance between productivity and decay responds to climate change. Here, we report the sensitivity of labile soil organic-matter decay in tidal marshes to seasonal and latitudinal variations in temperature measured over a 3-year period. We find a moderate increase in decay rate at warmer temperatures (3-6% per °C, Q10 = 1.3-1.5). Despite the profound differences between microbial metabolism in wetlands and uplands, our results indicate a strong conservation of temperature sensitivity. Moreover, simple comparisons with organic-matter production suggest that elevated atmospheric CO2 and warmer temperatures will accelerate carbon accumulation in marsh soils, and potentially enhance their ability to survive sea-level rise.

  12. Major structural components in freshwater dissolved organic matter.

    PubMed

    Lam, Buuan; Baer, Andrew; Alaee, Mehran; Lefebvre, Brent; Moser, Arvin; Williams, Antony; Simpson, André J

    2007-12-15

    Dissolved organic matter (DOM) contains a complex array of chemical components that are intimately linked to many environmental processes, including the global carbon cycle, and the fate and transport of chemical pollutants. Despite its importance, fundamental aspects, such as the structural components in DOM remain elusive, due in part to the molecular complexity of the material. Here, we utilize multidimensional nuclear magnetic resonance spectroscopy to demonstrate the major structural components in Lake Ontario DOM. These include carboxyl-rich alicyclic molecules (CRAM), heteropolysaccharides, and aromatic compounds, which are consistent with components recently identified in marine dissolved organic matter. In addition, long-range proton-carbon correlations are obtained for DOM, which support the existence of material derived from linear terpenoids (MDLT). It is tentatively suggested that the bulk of freshwater dissolved organic matter is aliphatic in nature, with CRAM derived from cyclic terpenoids, and MDLT derived from linear terpenoids. This is in agreement with previous reports which indicate terpenoids as major precursors of DOM. At this time it is not clear in Lake Ontario whether these precursors are of terrestrial or aquatic origin or whether transformations proceed via biological and/ or photochemical processes.

  13. Assessing the biodegradability of terrestrially-derived organic matter in Scottish sea loch sediments

    NASA Astrophysics Data System (ADS)

    Loh, P. S.; Miller, A. E. J.; Reeves, A. D.; Harvey, S. M.; Overnell, J.

    2008-05-01

    Lignin oxidation products, oxygen uptake rates, molar organic carbon to nitrogen (OC/N) ratio (from bulk elemental analysis) and Rp values (from loss on ignition experiments, the ratio of the refractory to total organic matter, OM) were determined for sediments along transects of Loch Creran and Loch Etive. Lignin data indicated the importance of riverine inputs contributing to land-derived carbon in the lochs as total lignin (Λ, mg/100 mg organic carbon, OC) decreased from 0.69 to 0.45 and 0.70 to 0.29 from the head to outside of Loch Creran and Loch Etive, respectively. In addition, significant correlations of lignin content against total OM and OC (p<0.05) also suggested a distinct contribution of terrestrial OM to carbon pools in the lochs. The general trend of decreasing oxygen uptake rates from the head (20.8 mmole m-2 day-1) to mouth (9.4 mmole m-2 day-1) of Loch Creran indicates decomposition of OM. Biodegradability of the sedimentary OM was also characterized by the increase of Rp values from the head to mouth of the lochs: 0.40 to 0.80 in Loch Etive and 0.43 to 0.63 in Loch Creran. Furthermore, the molar OC/N ratio decreased from 11.2 to 6.4 in Loch Creran, and from 17.5 to 8.2 in Loch Etive. Derived rate constants for OM degradation were found to decrease from LC0 to LC1, and increase from RE5 to RE6. This work demonstrates that oxygen uptake rates, Rp values and molar OC/N ratio are able to serve as useful proxies to indicate the biodegradability of sedimentary OM.

  14. A stoichiometric organic matter decomposition model in a chemostat culture.

    PubMed

    Kong, Jude D; Salceanu, Paul; Wang, Hao

    2018-02-01

    Biodegradation, the disintegration of organic matter by microorganism, is essential for the cycling of environmental organic matter. Understanding and predicting the dynamics of this biodegradation have increasingly gained attention from the industries and government regulators. Since changes in environmental organic matter are strenuous to measure, mathematical models are essential in understanding and predicting the dynamics of organic matters. Empirical evidence suggests that grazers' preying activity on microorganism helps to facilitate biodegradation. In this paper, we formulate and investigate a stoichiometry-based organic matter decomposition model in a chemostat culture that incorporates the dynamics of grazers. We determine the criteria for the uniform persistence and extinction of the species and chemicals. Our results show that (1) if at the unique internal steady state, the per capita growth rate of bacteria is greater than the sum of the bacteria's death and dilution rates, then the bacteria will persist uniformly; (2) if in addition to this, (a) the grazers' per capita growth rate is greater than the sum of the dilution rate and grazers' death rate, and (b) the death rate of bacteria is less than some threshold, then the grazers will persist uniformly. These conditions can be achieved simultaneously if there are sufficient resources in the feed bottle. As opposed to the microcosm decomposition models' results, in a chemostat culture, chemicals always persist. Besides the transcritical bifurcation observed in microcosm models, our chemostat model exhibits Hopf bifurcation and Rosenzweig's paradox of enrichment phenomenon. Our sensitivity analysis suggests that the most effective way to facilitate degradation is to decrease the dilution rate.

  15. Elucidating Microbial Species-Specific Effects on Organic Matter Transformation in Marine Sediments

    NASA Astrophysics Data System (ADS)

    Mahmoudi, N.; Enke, T. N.; Beaupre, S. R.; Teske, A.; Cordero, O. X.; Pearson, A.

    2017-12-01

    Microbial transformation and decomposition of organic matter in sediments constitutes one of the largest fluxes of carbon in marine environments. Mineralization of sedimentary organic matter by microorganisms results in selective degradation such that bioavailable or accessible compounds are rapidly metabolized while more recalcitrant, complex compounds are preserved and buried in sediment. Recent studies have found that the ability to use different carbon sources appears to vary among microorganisms, suggesting that the availability of certain pools of carbon can be specific to the taxa that utilize the pool. This implies that organic matter mineralization in marine environments may depend on the metabolic potential of the microbial populations that are present and active. The goal of our study was to investigate the extent to which organic matter availability and transformation may be species-specific using sediment from Guaymas Basin (Gulf of California). We carried out time-series incubations using bacterial isolates and sterilized sediment in the IsoCaRB system which allowed us to measure the production rates and natural isotopic signatures (δ13C and Δ14C) of microbially-respired CO2. Separate incubations using two different marine bacterial isolates (Vibrio sp. and Pseudoalteromonas sp.) and sterilized Guaymas Basin sediment under oxic conditions showed that the rate and total quantity of organic matter metabolized by these two species differs. Approximately twice as much CO2 was collected during the Vibrio sp. incubation compared to the Pseudoalteromonas sp. incubation. Moreover, the rate at which organic matter was metabolized by the Vibrio sp. was much higher than the Pseudoalteromonas sp. indicating the intrinsic availability of organic matter in sediments may depend on the species that is present and active. Isotopic analyses of microbially respired CO2 will be used to constrain the type and age of organic matter that is accessible to each species

  16. New Approaches in Soil Organic Matter Fluorescence; A Solid Phase Fluorescence Approach

    NASA Astrophysics Data System (ADS)

    Bowman, M. M.; Sanclements, M.; McKnight, D. M.

    2017-12-01

    Fluorescence spectroscopy is a well-established technique to investigate the composition of organic matter in aquatic systems and is increasingly applied to soil organic matter (SOM). Current methods require that SOM be extracted into a liquid prior to analysis by fluorescence spectroscopy. Soil extractions introduce an additional layer of complexity as the composition of the organic matter dissolved into solution varies based upon the selected extractant. Water is one of the most commonly used extractant, but only extracts the water-soluble fraction of the SOM with the insoluble soil organic matter fluorescence remaining in the soil matrix. We propose the use of solid phase fluorescence on whole soils as a potential tool to look at the composition of organic matter without the extraction bias and gain a more complete understand of the potential for fluorescence as a tool in terrestrial studies. To date, the limited applications of solid phase fluorescence have ranged from food and agriculture to pharmaceutical with no clearly defined methods and limitations available. We are aware of no other studies that use solid phase fluorescence and thus no clear methods to look at SOM across a diverse set of soil types and ecosystems. With this new approach to fluorescence spectroscopy there are new challenges, such as blank correction, inner filter effect corrections, and sample preparation. This work outlines a novel method for analyzing soil organic matter using solid phase fluorescence across a wide range of soils collected from the National Ecological Observatory Network (NEON) eco-domains. This method has shown that organic matter content in soils must be diluted to 2% to reduce backscattering and oversaturation of the detector in forested soils. In mineral horizons (A) there is observed quenching of the humic-like organic matter, which is likely a result of organo-mineral complexation. Finally, we present preliminary comparisons between solid and liquid phase

  17. Elemental composition and functional groups in soil labile organic matter fractions

    USDA-ARS?s Scientific Manuscript database

    Labile organic matter fractions are major components involved in nutrient cycle in soil. In this chapter, we examine three labile organic matter fraction: light fraction (LF), humic acid (HA) and fulvic acid (HA) in Alabama cotton soils (ultisol) amended with chemical fertilizer (NH4NO3) and poult...

  18. Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars

    NASA Astrophysics Data System (ADS)

    Eigenbrode, Jennifer L.; Summons, Roger E.; Steele, Andrew; Freissinet, Caroline; Millan, Maëva; Navarro-González, Rafael; Sutter, Brad; McAdam, Amy C.; Franz, Heather B.; Glavin, Daniel P.; Archer, Paul D.; Mahaffy, Paul R.; Conrad, Pamela G.; Hurowitz, Joel A.; Grotzinger, John P.; Gupta, Sanjeev; Ming, Doug W.; Sumner, Dawn Y.; Szopa, Cyril; Malespin, Charles; Buch, Arnaud; Coll, Patrice

    2018-06-01

    Establishing the presence and state of organic matter, including its possible biosignatures, in martian materials has been an elusive quest, despite limited reports of the existence of organic matter on Mars. We report the in situ detection of organic matter preserved in lacustrine mudstones at the base of the ~3.5-billion-year-old Murray formation at Pahrump Hills, Gale crater, by the Sample Analysis at Mars instrument suite onboard the Curiosity rover. Diverse pyrolysis products, including thiophenic, aromatic, and aliphatic compounds released at high temperatures (500° to 820°C), were directly detected by evolved gas analysis. Thiophenes were also observed by gas chromatography–mass spectrometry. Their presence suggests that sulfurization aided organic matter preservation. At least 50 nanomoles of organic carbon persists, probably as macromolecules containing 5% carbon as organic sulfur molecules.

  19. Impacts of heterogeneous organic matter on phenanthrene sorption--Equilibrium and kinetic studies with aquifer material

    USGS Publications Warehouse

    Karapanagioti, Hrissi K.; Kleineidam, Sybille; Sabatini, David A.; Grathwohl, Peter; Ligouis, Bertrand

    2000-01-01

    Sediment organic matter heterogeneity in sediments is shown to impact the sorption behavior of contaminants. We investigated the sorptive properties as well as the composition of organic matter in different subsamples (mainly grain size fractions) of the Canadian River Alluvium (CRA). Organic petrography was used as a new tool to describe and characterize the organic matter in the subsamples. The samples studied contained many different types of organic matter including bituminous coal particles. Differences in sorption behavior were explained based on these various types of organic matter. Subsamples containing predominately coaly, particulate organic matter showed the highest Koc, the highest nonlinearity of sorption isotherms and the slowest sorption kinetics. Soil subsamples with organic matter present as organic coatings around the quartz grains evidenced the lowest Koc, the most linear sorption isotherms and the fastest sorption kinetics, which was not limited by slow intraparticle diffusion. Due to the high sorption capacity of the coaly particles even when it is present as only a small fraction of the composite organic content (<3%) causes Koc values which are much higher than expected for soil organic matter (e.g. Koc − Kow relationships). The results show that the identification and quantification of the coaly particles within a sediment or soil sample is a prerequisite in order to understand or predict sorption behavior of organic pollutants.

  20. Absorption and fluorescence properties of colored dissolved organic matter in the Ross Sea during austral summer

    NASA Astrophysics Data System (ADS)

    D'Sa, E. J.; Kim, H. C.; Ha, S. Y.

    2016-12-01

    Colored dissolved organic matter (CDOM) spectral absorption and excitation-emission matrix (EEMs) fluorescence with parallel factor analysis (PARAFAC) were examined in the Ross Sea during a survey conducted on board the R/V Araon in the austral summer of 14/15. CDOM absorption at 355 nm ranged from 0.06 to 1.14 m-1 while spectral slope S calculated between 275-295 nm wavelength ranged from 18.83 to 33.32 µm-1 with water masses playing an important role in its variability. Spectral slope S decreased with increasing CDOM absorption indicating the strong role of photo-oxidation on CDOM abundance during the summer. PARAFAC analysis of EEM data identified two humic-like (terrestrial and marine-like) and a protein-like (tryptophan-like) component. The two humic-like components were well correlated with little variability spatially and across the water column ( 0-100 m) likely indicating more refractory material. The protein-like fluorescent component was relatively quite variable supporting the autochthonous production of this fluorescent component in the highly productive Ross Sea waters.

  1. Energy Transformations of Soil Organic Matter in a Changing World

    NASA Astrophysics Data System (ADS)

    Herrmann, A. M.; Coucheney, E.; Grice, S. M.; Ritz, K.; Harris, J.

    2011-12-01

    The role of soils in governing the terrestrial carbon balance is acknowledged as being important but remains poorly understood within the context of climate change. Soils exchange energy with their surroundings and are therefore open systems thermodynamically, but little is known how energy transformations of decomposition processes are affected by temperature. Soil organic matter and the soil biomass can be conceptualised as analogous to the 'fuel' and 'biological engine' of the earth, respectively, and are pivotal in driving the belowground carbon cycle. Thermodynamic principles of soil organic matter decomposition were evaluated by means of isothermal microcalorimetry (TAM Air, TA Instruments, Sollentuna Sweden: (i) Mineral forest soils from the Flakaliden long-term nitrogen fertilisation experiment (Sweden) were amended with a range of different substrates representing structurally simple to complex, ecologically pertinent organic matter and heat signatures were determined at temperatures between 5 and 25°C. (ii) Thermodynamic and resource-use efficiencies of the biomass were determined in arable soils which received contrasting long-term management regimes with respect to organic matter and nitrogen since 1956. The work showed that (i) structurally labile components have higher activation energy and temperature dependence than structurally more complex organic components. This is, however, in contrast to the thermodynamic argument which suggests the opposite that reactions metabolising structurally complex, aromatic components have higher temperature dependence than reactions metabolising structurally more labile components. (ii) Microbial communities exposed to long-term stress by heavy metal and low pH were less thermodynamic efficient and showed a decrease in resource-use efficiency in comparison with conventional input regimes. Differences in efficiencies were mirrored in both the phenotypic and functional profiles of the communities. We will present our

  2. Marine methane paradox explained by bacterial degradation of dissolved organic matter

    NASA Astrophysics Data System (ADS)

    Repeta, Daniel J.; Ferrón, Sara; Sosa, Oscar A.; Johnson, Carl G.; Repeta, Lucas D.; Acker, Marianne; Delong, Edward F.; Karl, David M.

    2016-12-01

    Biogenic methane is widely thought to be a product of archaeal methanogenesis, an anaerobic process that is inhibited or outcompeted by the presence of oxygen and sulfate. Yet a large fraction of marine methane delivered to the atmosphere is produced in high-sulfate, fully oxygenated surface waters that have methane concentrations above atmospheric equilibrium values, an unexplained phenomenon referred to as the marine methane paradox. Here we use nuclear magnetic resonance spectroscopy to show that polysaccharide esters of three phosphonic acids are important constituents of dissolved organic matter in seawater from the North Pacific. In seawater and pure culture incubations, bacterial degradation of these dissolved organic matter phosphonates in the presence of oxygen releases methane, ethylene and propylene gas. Moreover, we found that in mutants of a methane-producing marine bacterium, Pseudomonas stutzeri, disrupted in the C-P lyase phosphonate degradation pathway, methanogenesis was also disabled, indicating that the C-P lyase pathway can catalyse methane production from marine dissolved organic matter. Finally, the carbon stable isotope ratio of methane emitted during our incubations agrees well with anomalous isotopic characteristics of seawater methane. We estimate that daily cycling of only about 0.25% of the organic matter phosphonate inventory would support the entire atmospheric methane flux at our study site. We conclude that aerobic bacterial degradation of phosphonate esters in dissolved organic matter may explain the marine methane paradox.

  3. Test procedure for determining organic matter content in soils : UV-VIS method.

    DOT National Transportation Integrated Search

    2010-11-01

    The Texas Department of Transportation has been having problems with organic matter in soils that they : stabilize for use as subgrade layers in road construction. The organic matter reduces the effectiveness of : common soil additives (lime/cement) ...

  4. Tracing organic matter sources in a tropical lagoon of the Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Alonso-Hernández, Carlos M.; Garcia-Moya, Alejandro; Tolosa, Imma; Diaz-Asencio, Misael; Corcho-Alvarado, Jose Antonio; Morera-Gomez, Yasser; Fanelli, Emanuela

    2017-09-01

    The natural protected lagoon of Guanaroca, located between Cienfuegos Bay and the Arimao River, Cuba, has been heavily impacted by human-induced environmental changes over the past century. Sources of organic matter in the Guanaroca lagoon and concentrations of radioisotopes (210Pb, 226Ra, 137Cs and 239,240Pu), as tracers of anthropogenic impacts, were investigated in a 78 cm sediment core. Variations in total organic carbon (TOC), total nitrogen (TN), stable isotopic composition (δ13C and δ15N) and ratio of total organic carbon to total nitrogen (C/N) were analysed. On such a basis, environmental changes in the lagoon were revealed. Down core variation patterns of the parameters representing sources of organic matter were predominantly related to the impacts of human activities. Up to the nineteenth century, the principal sources of organic matter to sediments (more than 80%) were a mixing of terrestrial vascular plants ( 48%) and freshwater phytoplankton ( 8%), with minimal contribution from the marine component ( 16%). In the period 1900-1980, due to the strong influence of human activities in the catchment area, the water exchange capacity of the lagoon declined substantially, as indicated by the relatively high proportion of organic matter originated from human activities (58%). Since 1980, as a result of management actions in the protected area, the lagoon has regained gradually its capability to exchange freshwater, showing sources of organic matter similar to the natural conditions recorded previous to 1900, although an indication of human impact (treated sewage contributed for 26% to the organic matter in sediments) was still observed and further management measures would be required.

  5. Soil organic matter content effects on dermal pesticide bioconcentration in American toads (Bufo americanus).

    PubMed

    Van Meter, Robin J; Glinski, Donna A; Henderson, W Matthew; Purucker, S Thomas

    2016-11-01

    Pesticides have been implicated as a major factor in global amphibian declines and may pose great risk to terrestrial phase amphibians moving to and from breeding ponds on agricultural landscapes. Dermal uptake from soil is known to occur in amphibians, but predicting pesticide availability and bioconcentration across soil types is not well understood. The present study was designed to compare uptake of 5 current-use pesticides (imidacloprid, atrazine, triadimefon, fipronil, and pendimethalin) in American toads (Bufo americanus) from exposure on soils with significant organic matter content differences (14.1% = high organic matter and 3.1% = low organic matter). We placed toads on high- or low-organic matter soil after applying individual current-use pesticides on the soil surface for an 8-h exposure duration. Whole body tissue homogenates and soils were extracted and analyzed using liquid chromatography-mass spectrometry to determine pesticide tissue and soil concentration, as well as bioconcentration factor in toads. Tissue concentrations were greater on the low-organic matter soil than the high-organic matter soil across all pesticides (average ± standard error; 1.23 ± 0.35 ppm and 0.78 ± 0.23 ppm, respectively), and bioconcentration was significantly higher for toads on the low-organic matter soil (analysis of covariance p = 0.002). Soil organic matter is known to play a significant role in the mobility of pesticides and bioavailability to living organisms. Agricultural soils typically have relatively lower organic matter content and serve as a functional habitat for amphibians. The potential for pesticide accumulation in amphibians moving throughout agricultural landscapes may be greater and should be considered in conservation and policy efforts. Environ Toxicol Chem 2016;35:2734-2741. © 2016 SETAC. © 2016 SETAC.

  6. Refractory Hodgkin lymphoma.

    PubMed

    von Tresckow, Bastian; Engert, Andreas

    2013-09-01

    Despite the advances in the treatment of Hodgkin Lymphoma, patients with refractory disease still have a poor prognosis. Hodgkin Lymphoma can be refractory at first diagnosis or might become refractory later in the course of treatment. Both situations represent a therapeutic challenge. Intensified chemotherapy with BEACOPP escalated has been evaluated in early unfavourable and advanced Hodgkin Lymphoma and led to an improved tumour control and reduced rates of refractory disease. Furthermore, there is growing evidence for the role of tandem autologous transplant in breaking refractory disease. For patients relapsing after autologous transplant, more recent analyses have reported outcome and defined risk factors. The antibody drug conjugate brentuximab vedotin is a new, highly effective therapeutic option for these patients. Dose-reduced allogeneic transplant is a therapeutic alternative for patients relapsing after autologous transplant, but induction of a remission is the prerequisite for a successful allogeneic transplant. Brentuximab vedotin has been evaluated as a bridge to allogeneic transplant for patients refractory to conventional treatment. Recent therapeutic advances have improved the prognosis of Hodgkin Lymphoma by prevention or successful treatment of refractory disease. The use of new drugs such as brentuximab vedotin will hopefully further increase the cure rates.

  7. The origin of organic matter in the Martian meteorite ALH84001.

    PubMed

    Becker, L; Popp, B; Rust, T; Bada, J L

    1999-01-01

    Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta 13C values for the organic matter associated with the carbonate globules averaged -26% and is attributed to terrestrial contamination. In contrast, the delta 13C values for the organic matter associated with the bulk matrix material yielded a value of -15%. The only common carbon sources on the Earth that yield similar delta 13C values, other then some diagenetically altered marine carbonates, are C4 plants. A delta 13C value of -15%, on the other hand, is consistent with a kerogen-like component, the most ubiquitous form of organic matter found in carbonaceous chondrites such as the Murchison meteorite. Examination of the carbonate globules and bulk matrix material using laser desorption mass spectrometry (LDMS) indicates the presence of a high molecular weight organic component which appears to be extraterrestrial in origin, possibly derived from the exogenous delivery of meteoritic or cometary debris to the surface of Mars.

  8. The origin of organic matter in the Martian meteorite ALH84001.

    PubMed

    Becker, L; Popp, B; Rust, T; Bada, J L

    1999-03-30

    Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta 13C values for the organic matter associated with the carbonate globules averaged -26% and is attributed to terrestrial contamination. In contrast, the delta 13C values for the organic matter associated with the bulk matrix material yielded a value of -15%. The only common sources of carbon on the Earth that yield similar delta 13C values, other then some diagenetically altered marine carbonates, are C4 plants. A delta 13C value of -15%, on the other hand, is consistent with a kerogen-like component, the most ubiquitous form of organic matter found in carbonaceous chondrites such as the Murchison meteorite. Examination of the carbonate globules and bulk matrix material using laser desorption mass spectrometry (LDMS) indicates the presence of a high molecular weight organic component which appears to be extraterrestrial in origin, possibly derived from the exogenous delivery, of meteoritic or cometary debris to the surface of Mars.

  9. Organic matter and the geotechnical properties of submarine sediments

    NASA Astrophysics Data System (ADS)

    Keller, George H.

    1982-09-01

    Continental slope deposits off Peru and Oregon where coastal upwelling is a pronounced oceanographic process possess significant concentrations of organic carbon. Geotechnical properties are altered to varying degrees by the organic matter. Organic matter absorbs water and causes clay-size particles to aggregate forming an open fabric. This causes unusually high water contents and plasticity and exceptionally low wet bulk densities. Some of these deposits show notable increases in shear strength, sensitivity and degree of apparent overconsolidation. Owing to the unique geotechnical properties, sediment stability characteristics are considered to be poor in situations of excess pore pressures. Failure appears to take the form of a fluidized flow somewhat similar to the quick clays of Scandinavia.

  10. Riverine transport of terrestrial organic matter to the North Catalan margin, NW Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Sanchez-Vidal, Anna; Higueras, Marina; Martí, Eugènia; Liquete, Camino; Calafat, Antoni; Kerhervé, Philippe; Canals, Miquel

    2013-11-01

    Rivers are the primary pathway for organic matter transport from the terrestrial to the marine environment and, thus, river fluxes are critical in regulating the quantity of terrestrial organic matter that reaches the coastal ecosystems. Hydrodynamic processes typical of the coastal zone can lead to the transport of terrestrial organic matter across the continental shelf and beyond. Such organic matter can eventually reach the deep margin and basin ecosystems. Riverine inputs of organic matter to the sea can be a significant food source to marine ecosystems contributing to carbon cycling in these ecosystems. In order to assess the marine carbon cycle it is essential to know the biogeochemical characteristics and temporal dynamics of the fluvial organic matter input discharged by rivers to the coastal zone. In this study we present a one and a half year long (November 2008 to May 2010) assessment on organic carbon (OC) and nitrogen (N) inputs from the three main rivers discharging into the North Catalan margin (Tordera, Ter and Fluvià, from south to north). Furthermore, we investigate the characteristics of the particulate organic matter discharged by these rivers by means of stable isotopic (δ13C and δ15N) and grain size analyses. We found that the hydrological regime of the rivers is a relevant factor in regulating the quantity and mediating the quality of organic matter inputs to the North Catalan margin. Overall, the three main rivers discharging into the study area deliver 1266 and 159 tonnes of terrestrial OC and N per year, respectively, to the coastal zone. Most of the OC and N load is transported during floods, which indicates that the Mediterranean climate of the area, with a strong seasonal contrast in precipitation, determines the timing of the main inputs of OC and N to the sea. Therefore, the annual OC and N load experiences a high temporal variability associated to the number and magnitude of floods with in each hydrological year. In addition, we

  11. Effect of organic matter on CO(2) hydrate phase equilibrium in phyllosilicate suspensions.

    PubMed

    Park, Taehyung; Kyung, Daeseung; Lee, Woojin

    2014-06-17

    In this study, we examined various CO2 hydrate phase equilibria under diverse, heterogeneous conditions, to provide basic knowledge for successful ocean CO2 sequestration in offshore marine sediments. We investigated the effect of geochemical factors on CO2 hydrate phase equilibrium. The three-phase (liquid-hydrate-vapor) equilibrium of CO2 hydrate in the presence of (i) organic matter (glycine, glucose, and urea), (ii) phyllosilicates [illite, kaolinite, and Na-montmorillonite (Na-MMT)], and (iii) mixtures of them was measured in the ranges of 274.5-277.0 K and 14-22 bar. Organic matter inhibited the phase equilibrium of CO2 hydrate by association with water molecules. The inhibition effect decreased in the order: urea < glycine < glucose. Illite and kaolinite (unexpandable clays) barely affected the CO2 hydrate phase equilibrium, while Na-MMT (expandable clay) affected the phase equilibrium because of its interlayer cations. The CO2 hydrate equilibrium conditions, in the illite and kaolinite suspensions with organic matter, were very similar to those in the aqueous organic matter solutions. However, the equilibrium condition in the Na-MMT suspension with organic matter changed because of reduction of its inhibition effect by intercalated organic matter associated with cations in the Na-MMT interlayer.

  12. Understanding refractory failures

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

    Bases, G.J.

    2006-01-15

    Compared to most pieces of a power plant, refractory costs very little to install. Yet, if improperly manufactured, specified, stored, mixed installed, cured, or dried, refractory may cause problems that can significantly decrease a plant's operating efficiency and flexibility. Like Rodney Dangerfield, refractory design and installation deserve more respect. 4 photos.

  13. Non-invasive localization of organic matter in soil aggregates using SR-μCT

    NASA Astrophysics Data System (ADS)

    Peth, Stephan; Mordhorst, Anneka; Chenu, Claire; Uteau Puschmann, Daniel; Garnier, Patricia; Nunan, Naoise; Pot, Valerie; Beckmann, Felix; Ogurreck, Malte

    2014-05-01

    Knowledge of the location of soil organic matter (SOM) and its spatial association to soil structure is an important step in improving modeling approaches for simulating organic matter turnover processes. Advanced models for carbon mineralization are able to account for the 3D distribution of SOM which is assumed to influence mineralisation. However, their application is still limited by the fact that no method exists to non-invasively determine the 3D spatial distribution of SOM in structured soils. SR-based X-ray microtomography (SR-µCT) is an advanced and promising tool in gaining knowledge on the 3-dimensional organization of soil phases (minerals, organic matter, water, air) which on a voxel level could be implemented into spatially explicit models. However, since the contrast of linear attenuation coefficients of soil organic matter on the one hand and mineral components and water on the other hand are relatively low, especially when materials are finely dispersed, organic matter within the soil pore space is often not resolved in ordinary X-ray absorption contrast imaging. To circumvent this problem we have developed a staining procedure for organic matter using Osmium-tetroxide since Osmium is an element with an absorption edge at a higher X-ray energy level. Osmium is known from transmission electron microscopy analysis (TEM) to stain organic matter specifically and irreversibly while having an absorption edge at approximately 74 keV. We report on the application of a novel Osmium vapor staining method to analyze differences in organic matter content and identify small scale spatial distribution of SOM in soil aggregates. To achieve this we have taken soil aggregate samples (6-8 mm across) obtained from arable soils differing in soil management. Aggregate samples were investigated by synchrotron-based X-ray microtomography (SR-µCT) after staining the sample with Osmium-tetroxide (OsO4) vapor. We utilized the monochromatic X-ray beam to locate osmium

  14. Evidence for Changes in 81PIWild 2 Organic Matter Since Collection and Comparison of 82PIWild 2 and IDP Organic Matter to Access the Thermal Effects of Aerogel Capture

    NASA Technical Reports Server (NTRS)

    Wirick, S.; Flynn, G. J.; Keller, L.; Messenger, Nakamura; Sandford, S. A.; Zolensky, M. E.; Peltzer, C.; Jacobsen, C.

    2009-01-01

    NASA s Stardust spacecraft collected cometary material during its passage through the dust coma of comet 81P/Wild 2 on January 2nd, 2004 and delivered this material to Earth on January 15th 2006. The first fragment we analyzed during the preliminary examination was partially vaporized by the X-ray beam. The carbonaceous material that survived was re-analysis approx.2 months later and the carbon spectrum for this material had significantly changed from what we first observed.. We have observed similar changes to the carbonaceous matter in some interplanetary dust particles ( IDPs). Some of the 81P/Wild 2 organic matter volatilized upon impact with the aerogel as observed using IR spectroscopy where IR spectra were collected several mms away from sample tracks [1]. The time-temperature profile experienced by any particular 81P/Wild 2 grain during aerogel capture is not known, although Brownlee, et al. suggest that fine-grained materials, <1 micron in size, fragmented and then partially vaporized during collection, while particles much larger then 1 micron in size were captured intact [2]. Nearly all organic matter is subject to thermal alteration. To assess the heating and alteration experienced by the 81P/Wild 2 organic matter during capture we are comparing 81P/Wild2 organic matter with IDP organic matter where we have evidence of heating in the IDP [3,4].

  15. Influence of soil organic matter composition on the partition of organic compounds

    USGS Publications Warehouse

    Rutherford, D.W.; Chiou, C.T.; Klle, D.E.

    1992-01-01

    The sorption at room temperature of benzene and carbon tetrachloride from water on three high-organic-content soils (muck, peat, and extracted peat) and on cellulose was determined in order to evaluate the effect of sorbent polarity on the solute partition coefficients. The isotherms are highly linear for both solutes on all the organic matter samples, which is consistent with a partition model. For both solutes, the extracted peat shows the greatest sorption capacity while the cellulose shows the lowest capacity; the difference correlates with the polar-to-nonpolar group ratio [(O + N)/C] of the sorbent samples. The relative increase of solute partition coefficient (Kom) with a decrease of sample polar content is similar for both solutes, and the limiting sorption capacity on a given organic matter sample is comparable between the solutes. This observation suggests that one can estimate the polarity effect of a sample of soil organic matter (SOM) on Kom of various nonpolar solutes by determining the partition coefficient of single nonpolar solute when compositional analysis of the SOM is not available. The observed dependence of Kom on sample polarity is used to account for the variation of Kom values of individual compounds on different soils that results from change in the polar group content of SOM. On the assumption that the carbon content of SOM in "ordinary soils" is 53-63%, the calculated variation of Kom is a factor of ???3. This value is in agreement with the limit of variation of most Kom data with soils of relatively high SOM contents.

  16. Effect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems

    USGS Publications Warehouse

    Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Lewan, Mike; Sun, Xun; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

    2013-01-01

    A series of CH4 adsorption experiments on natural organic-rich shales, isolated kerogen, clay-rich rocks, and artificially matured Woodford Shale samples were conducted under dry conditions. Our results indicate that physisorption is a dominant process for CH4 sorption, both on organic-rich shales and clay minerals. The Brunauer–Emmett–Teller (BET) surface area of the investigated samples is linearly correlated with the CH4 sorption capacity in both organic-rich shales and clay-rich rocks. The presence of organic matter is a primary control on gas adsorption in shale-gas systems, and the gas-sorption capacity is determined by total organic carbon (TOC) content, organic-matter type, and thermal maturity. A large number of nanopores, in the 2–50 nm size range, were created during organic-matter thermal decomposition, and they significantly contributed to the surface area. Consequently, methane-sorption capacity increases with increasing thermal maturity due to the presence of nanopores produced during organic-matter decomposition. Furthermore, CH4 sorption on clay minerals is mainly controlled by the type of clay mineral present. In terms of relative CH4 sorption capacity: montmorillonite ≫ illite – smectite mixed layer > kaolinite > chlorite > illite. The effect of rock properties (organic matter content, type, maturity, and clay minerals) on CH4 adsorption can be quantified with the heat of adsorption and the standard entropy, which are determined from adsorption isotherms at different temperatures. For clay-mineral rich rocks, the heat of adsorption (q) ranges from 9.4 to 16.6 kJ/mol. These values are considerably smaller than those for CH4 adsorption on kerogen (21.9–28 kJ/mol) and organic-rich shales (15.1–18.4 kJ/mol). The standard entropy (Δs°) ranges from -64.8 to -79.5 J/mol/K for clay minerals, -68.1 to -111.3 J/mol/K for kerogen, and -76.0 to -84.6 J/mol/K for organic-rich shales. The affinity of CH4 molecules for sorption on organic matter

  17. Lability of Secondary Organic Particulate Matter

    DOE PAGES

    Liu, Pengfei; Li, Yong Jie; Wang, Yan; ...

    2016-10-24

    Accurate simulations of the consenctrations of atmospheric organic particulate matter (PM) are needed for predicting energy flow in the Earth’s climate system. In the past, simulations of organic PM widely assume equilibrium partitioning of semivolatile organic compounds (SVOCs) between the PM and surrounding vapor. Herein, we test this assumption by measuring evaporation rates and associated vapor mass concentration of organic films representative of atmospheric PM. For films representing anthropogenic PM, evaporation rates and vapor mass concentrations increased above a threshold relative humidity (RH), indicating equilibrium partitioning above a transition RH but not below. In contrast for films representing biogenic PM,more » no threshold was observed, indicating equilibrium partitioning at all RHs. The results suggest that the mass lability of atmospheric organic PM can differ in consequential ways among Earth’s natural biomes, polluted regions, and regions of land-use change, and these differences need to be considered when simulating atmospheric organic PM.« less

  18. Organic matter degradation drives benthic cyanobacterial mat abundance on Caribbean coral reefs.

    PubMed

    Brocke, Hannah J; Polerecky, Lubos; de Beer, Dirk; Weber, Miriam; Claudet, Joachim; Nugues, Maggy M

    2015-01-01

    Benthic cyanobacterial mats (BCMs) are impacting coral reefs worldwide. However, the factors and mechanisms driving their proliferation are unclear. We conducted a multi-year survey around the Caribbean island of Curaçao, which revealed highest BCM abundance on sheltered reefs close to urbanised areas. Reefs with high BCM abundance were also characterised by high benthic cover of macroalgae and low cover of corals. Nutrient concentrations in the water-column were consistently low, but markedly increased just above substrata (both sandy and hard) covered with BCMs. This was true for sites with both high and low BCM coverage, suggesting that BCM growth is stimulated by a localised, substrate-linked release of nutrients from the microbial degradation of organic matter. This hypothesis was supported by a higher organic content in sediments on reefs with high BCM coverage, and by an in situ experiment which showed that BCMs grew within days on sediments enriched with organic matter (Spirulina). We propose that nutrient runoff from urbanised areas stimulates phototrophic blooms and enhances organic matter concentrations on the reef. This organic matter is transported by currents and settles on the seabed at sites with low hydrodynamics. Subsequently, nutrients released from the organic matter degradation fuel the growth of BCMs. Improved management of nutrients generated on land should lower organic loading of sediments and other benthos (e.g. turf and macroalgae) to reduce BCM proliferation on coral reefs.

  19. Priming of native soil organic matter by pyrogenic organic matter

    NASA Astrophysics Data System (ADS)

    DeCiucies, Silene; Dharmakeerthi, Saman; Whitman, Thea; Woolf, Dominic; Lehmann, Johannes

    2015-04-01

    Priming, in relation to pyrogenic organic matter (PyOM), describes the change in mineralization rate of non-pyrogenic ("native") soil organic matter (nSOM) due to the addition of PyOM. Priming may be 'positive', in that the addition of pyC increases the mineralization rate of native SOM, or 'negative', in that the mineralization rate of nSOM is decreased. Reasons for increased mineralization may include: (i) co-metabolism: microbial decomposition of labile C-additions increases microbial activity, and facilitates additional decomposition of npSOC by active enzymes; (ii) stimulation: substrate additions result in lifted pH, nutrient, oxygen, or water constraints resulting in increased microbial activity. Decreased mineralization may be a result of: (i) inhibition: the opposite of stimulation whereby constraints are aggravated by substrate addition. Substrate addition may also cause inhibition by interfering with enzymes or signaling compounds; (ii) preferential substrate utilization: labile fraction of PyOM additions are preferentially used up by microbes thus causing a decrease in nSOC decomposition; (iii) sorption: organic compounds are adsorbed onto PyOM surfaces, decreasing their rate of mineralization; (iv) stabilization: formation of organo-mineral associations forms stable SOC pools. We have conducted a suite of experiments to investigate these potential interactions. In a seven year long incubation study, PyOM additions increased total OM mineralization for the first 2.5 years, was equal to control after 6.2 years, and was 3% lower after 7.1 years. Cumulative nSOM mineralization was 23% less with the PyOM additions than without, and over 60% of the added PyOM was present in the labile soil fraction after the 7.1 year incubation. Two additional incubation studies, one with and without plants, showed greater nSOM mineralization in the short term and lower nSOM mineralization over the long term. Increased nSOC mineralization due to the presence of plants was

  20. Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars.

    PubMed

    Eigenbrode, Jennifer L; Summons, Roger E; Steele, Andrew; Freissinet, Caroline; Millan, Maëva; Navarro-González, Rafael; Sutter, Brad; McAdam, Amy C; Franz, Heather B; Glavin, Daniel P; Archer, Paul D; Mahaffy, Paul R; Conrad, Pamela G; Hurowitz, Joel A; Grotzinger, John P; Gupta, Sanjeev; Ming, Doug W; Sumner, Dawn Y; Szopa, Cyril; Malespin, Charles; Buch, Arnaud; Coll, Patrice

    2018-06-08

    Establishing the presence and state of organic matter, including its possible biosignatures, in martian materials has been an elusive quest, despite limited reports of the existence of organic matter on Mars. We report the in situ detection of organic matter preserved in lacustrine mudstones at the base of the ~3.5-billion-year-old Murray formation at Pahrump Hills, Gale crater, by the Sample Analysis at Mars instrument suite onboard the Curiosity rover. Diverse pyrolysis products, including thiophenic, aromatic, and aliphatic compounds released at high temperatures (500° to 820°C), were directly detected by evolved gas analysis. Thiophenes were also observed by gas chromatography-mass spectrometry. Their presence suggests that sulfurization aided organic matter preservation. At least 50 nanomoles of organic carbon persists, probably as macromolecules containing 5% carbon as organic sulfur molecules. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  1. The organic matter of the different ages fallow Luvisols

    NASA Astrophysics Data System (ADS)

    Giniyatullin, K. G.; Valeeva, A. A.; Smirnova, E. V.; Okunev, R. V.; Latipova, L. I.

    2018-01-01

    The study of the change in the humus state of the fallow Luvisols of different ages under the influence of weeds and meadow vegetation was carried out in dynamics (after 5 years). It is shown that both under weedy and meadow vegetation there is a statistically significant accumulation of organic matter in the upper part of the long-arable horizon. Based on the study of composition and spectral properties of soil organic matter in fallow soils of different ages concluded that the significant qualitative change of the humus state of fallow soils requires significant time, measured at least decades.

  2. Soil Organic Matter and Soil Productivity: Searching for the Missing Link

    Treesearch

    Felipe G. Sanchez

    1998-01-01

    Soil-organic matter (SOM) is a complex array of components including soil fauna and flora at different stages of decomposition (Berg et al., 1982). Its concentration in soils can vary from 0.5% in mineral soils to almost 100% in peat soils (Brady, 1974). Organic matter (OM) in the surface mineral soil is considered a major determinant of forest ecosystem productivity...

  3. Depletion of 13C in Cretaceous marine organic matter: Source, diagenetic, or environmental sigal?

    USGS Publications Warehouse

    Dean, W.E.; Arthur, M.A.; Claypool, G.E.

    1986-01-01

    Geochemical studies of Cretaceous strata rich in organic carbon (OC) from Deep Sea Drilling Project (DSDP) sites and several land sections reveal several consistent relationships among amount of OC, hydrocarbon generating potential of kerogen (measured by pyrolysis as the hydrogen index, HI), and the isotopic composition of the OC. First, there is a positive correlation between HI and OC in strata that contain more than about 1% OC. Second, percent OC and HI often are negatively correlated with carbon isotopic composition (?? 13C) of kerogen. The relationship between HI and OC indicates that as the amount of organic matter increases, this organic matter tends to be more lipid rich reflecting the marine source of the organic matter. Cretaceous samples that contain predominantly marine organic matter tend to be isotopically lighter than those that contain predominantly terrestrial organic matter. Average ?? 13C values for organic matter from most Cretaceous sites are between -26 and -28???, and values heavier than about -25??? occur at very few sites. Most of the ?? 13C values of Miocene to Holocene OC-rich strata and modern marine plankton are between -16 to -23???. Values of ??13C of modern terrestrial organic matter are mostly between -23 and -33???. The depletion of terrestial OC in 13C relative to marine planktonic OC is the basis for numerous statements in the literature that isotopically light Cretaceous organic matter is of terrestrial origin, even though other organic geochemical and(or) optical indicators show that the organic matter is mainly of marine origin. A difference of about 5??? in ?? 13C between modern and Cretaceous OC-rich marine strata suggests either that Cretaceous marine planktonic organic matter had the same isotopic signature as modern marine plankton and that signature has been changed by diagenesis, or that OC derived from Cretaceous marine plankton was isotopically lighter by about 5??? relative to modern plankton OC. Diagenesis does

  4. The Effect of paper mill waste and sewage sludge amendments on soil organic matter

    NASA Astrophysics Data System (ADS)

    Méndez, Ana; Barriga, Sandra; Guerrero, Francisca; Gascó, Gabriel

    2013-04-01

    In general, Mediterranean soils have low organic matter content, due to the climate characteristics of this region and inadequate land management. Traditionally, organic wastes such as manure are used as amendment in order to improve the soil quality, increasing soil fertility by the accumulation of nitrogen, phosphorus and other plant nutrients in the soil. In the last decade, other anthropogenic organic wastes such as sewage sludge or paper waste materials have been studied as soil amendments to improve physical, chemical and biological properties of soils. The objective of the present work was to study the influence of waste from a paper mill and sewage sludge amendments on soil organic matter. For this reason, soil organic matter evolution was studied using thermogravimetric analysis (TGA), the derivative (dTG) and differential thermal analysis (DTA). Thermal analytical techniques have the advantage of using full samples without pre-treatments and have been extensively used to study the evolution of organic matter in soils, to evaluate composting process or to study the evolution of organic matter of growing media.

  5. Insight into dissolved organic matter fractions in Lake Wivenhoe during and after a major flood.

    PubMed

    Aryal, Rupak; Grinham, Alistair; Beecham, Simon

    2016-03-01

    Dissolved organic matter is an important component of biogeochemical processes in aquatic environments. Dissolved organic matter may consist of a myriad of different fractions and resultant processing pathways. In early January 2011, heavy rainfall occurred across South East Queensland, Australia causing significant catchment inflow into Lake Wivenhoe, which is the largest water supply reservoir for the city of Brisbane, Australia. The horizontal and vertical distributions of dissolved organic matter fractions in the lake during the flood period were investigated and then compared with stratified conditions with no catchment inflows. The results clearly demonstrate a large variation in dissolved organic matter fractions associated with inflow conditions compared with stratified conditions. During inflows, dissolved organic matter concentrations in the reservoir were fivefold lower than during stratified conditions. Within the dissolved organic matter fractions during inflow, the hydrophobic and humic acid fractions were almost half those recorded during the stratified period whilst low molecular weight neutrals were higher during the flood period compared to during the stratified period. Information on dissolved organic matter and the spatial and vertical variations in its constituents' concentrations across the lake can be very useful for catchment and lake management and for selecting appropriate water treatment processes.

  6. Removing organic matter from sulfate-rich wastewater via sulfidogenic and methanogenic pathways.

    PubMed

    Vilela, Rogerio Silveira; Damianovic, Márcia Helena Rissato Zamariolli; Foresti, Eugenio

    2014-01-01

    The simultaneous organic matter removal and sulfate reduction in synthetic sulfate-rich wastewater was evaluated for various chemical oxygen demand (COD)/sulfate ratios applied in a horizontal-flow anaerobic immobilized sludge (HAIS) reactor. At higher COD/sulfate ratios (12.5 and 7.5), the removal of organic matter was stable, likely due to methanogenesis. A combination of sulfate reduction and methanogenesis was clearly established at COD/sulfate ratios of 3.0 and 1.9. At a COD/sulfate ratio of 1.0, the organic matter removal was likely influenced by methanogenesis inhibition. The quantity of sulfate removed at a COD/sulfate ratio of 1.0 was identical to that obtained at a ratio of 1.9, indicating a lack of available electron donors for sulfidogenesis. The sulfate reduction and organic matter removal were not maximized at the same COD/sulfate ratio; therefore, competitive inhibition must be the predominant mechanism in establishing an electron flow.

  7. Plutonium Immobilization and Mobilization by Soil Organic Matter

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

    Santschi, Peter H.; Schwehr, Kathleen A.; Xu, Chen

    The human and environmental risks associated with Pu disposal, remediation, and nuclear accidents scenarios stems mainly from the very long half-lives of several of its isotopes. The SRS, holding one-third of the nation’s Pu inventory, has a long-term stewardship commitment to investigation of Pu behavior in the groundwater and downgradient vast wetlands. Pu is believed to be essentially immobile due to its low solubility and high particle reactivity to mineral phase or natural organic matter (NOM). For example, in sediments collected from a region of SRS, close to a wetland and a groundwater plume, 239,240Pu concentrations suggest immobilization by NOMmore » compounds, as Pu correlate with NOM contents. Micro-SXRF data indicate, however, that Pu does not correlate with Fe. However, previous studies reported Pu can be transported several kilometers in surface water systems, in the form of a colloidal organic matter carrier, through wind/water interactions. The role of NOM in both immobilizing or re-mobilizing Pu thus has been demonstrated. Our results indicate that more Pu (IV) than (V) was bound to soil colloidal organic matter (COM), amended at far-field concentrations. Contrary to expectations, the presence of NOM in the F-Area soil did not enhance Pu fixation to the organic-rich soil, when compared to the organic-poor soil or the mineral phase from the same soil source, due to the formation of COM-bound Pu. Most importantly, Pu uptake by organic-rich soil decreased with increasing pH because more NOM in the colloidal size desorbed from the particulate fraction at elevated pH, resulting in greater amounts of Pu associated with the COM fraction. This is in contrast to previous observations with low-NOM sediments or minerals, which showed increased Pu uptake with increasing pH levels. This demonstrates that despite Pu immobilization by NOM, COM can convert Pu into a more mobile form. Sediment Pu concentrations in the SRS F-Area wetland were correlated to total

  8. A Robust Analysis Method For Δ13c Signal Of Bulk Organic Matter In Speleothems

    NASA Astrophysics Data System (ADS)

    Bian, F.; Blyth, A. J.; Smith, C.; Baker, A.

    2017-12-01

    Speleothems preserve organic matter that is derived from both the surface soil and cave environments. This organic matter can be used to understand paleoclimate and paleoenvironments. However, a stable and quick micro-analysis method to measure the δ13C signals from speleothem organic matter separate from the total δ13C remains absent. And speleothem organic geochemistry is still relatively unexplored compared to inorganic geochemistry. In this research, for the organic matter analysis, bulk homogeneous power samples were obtained from one large stalagmite. These were dissolved by phosphoric acid to produce the aqueous solution. Then, the processed solution was degassed through a rotational vacuum concentrator. A liquid chromatograph was coupled to IRMS to control the oxidization and the measurement of analytes. This method is demonstrated to be robust for the analysis of speleothem d13C organic matter analysis under different preparation and instrumental settings, with the low standard deviation ( 0.2‰), and low sample consumption (<25 mg). Considering the complexity of cave environments, this method will be useful in further investigations the δ13C of entrapped organic matter and environmental controls in other climatic and ecological contexts, including the determination of whether vegetation or soil microbial activity is the dominant control on speleothem d13C of organic matter.

  9. Organic matter dynamics and stable isotopes for tracing sources of suspended sediment

    NASA Astrophysics Data System (ADS)

    Schindler Wildhaber, Y.; Liechti, R.; Alewell, C.

    2012-01-01

    Suspended sediment (SS) and organic matter in rivers can harm brown trout Salmo trutta by impact on health and fitness of free swimming fish and siltation of the riverbed. The later results in a decrease of hydraulic conductivity and therefore smaller oxygen supply to the salmonid embryos. Additionally, oxygen demand within riverbeds will increase as the pool of organic matter increases. We assessed the temporal and spatial dynamics of sediment, carbon (C) and nitrogen (N) during the brown trout spawning season and used C isotopes as well as the C/N atomic ratio to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13Ctot and 15N as input isotopes was used to quantify the sources of SS in respect of time and space. Organic matter fractions in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and precipitation probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ13Corg. Organic matter in SS increased from up- to downstream due to pasture and arable land. The fraction of SS originating from upper watershed riverbed sediment increased at all sites during high flow. Its mean fraction decreased from up- to downstream. During base flow conditions, the major sources of SS are pasture and arable land. The later increased during rainy and warmer periods probably due to snow melting and erosion processes. These modeling results support the measured increased DOC and NO3 concentrations during high flow.

  10. Refractory Materials for Flame Deflector Protection System Corrosion Control: Refractory Ceramics Literature Survey

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark; Perusich, Stephen; Whitten, Mary C.; Trejo, David; Zidek, Jason; Sampson, Jeffrey W.; hide

    2009-01-01

    Ceramics can be defmed as a material consisting of hard brittle properties produced from inorganic and nonmetallic minerals made by firing at high temperatures. These materials are compounds between metallic and nonmetallic elements and are either totally ionic, or predominately ionic but having some covalent character. This definition allows for a large range of materials, not all applicable to refractory applications. As this report is focused on potential ceramic materials for high temperature, aggressive exposure applications, the ceramics reviewed as part of this report will focus on refractory ceramics specifically designed and used for these applications. Ceramic materials consist of a wide variety of products. Callister (2000) 1 characterized ceramic materials into six classifications: glasses, clay products, refractories, cements, abrasives, and advanced ceramics. Figure 1 shows this classification system. This review will focus mainly on refractory ceramics and cements as in general, the other classifications are neither applicable nor economical for use in large structures such as the flame trench. Although much work has been done in advanced ceramics over the past decade or so, these materials are likely cost prohibitive and would have to be fabricated off-site, transported to the NASA facilities, and installed, which make these even less feasible. Although the authors reviewed the literature on advanced ceramic refractories 2 center dot 3 center dot 4 center dot 5 center dot 6 center dot 7 center dot 8 center dot 9 center dot 10 center dot 11 center dot 12 after the review it was concluded that these materials should not be ' the focus of this report. A review is in progress on materials and systems for prefabricated refractory ceramic panels, but this review is focusing more on typical refractory materials for prefabricated systems, which could make the system more economically feasible. Refractory ceramics are used for a wide variety of applications

  11. Contribution of plant lignin to the soil organic matter formation and stabilization

    USDA-ARS?s Scientific Manuscript database

    Lignin is the third most abundant plant constituent after cellulose and hemicellulose and thought to be one of the building blocks for soil organic matter formation. Lignin can be used as a predictor for long-term soil organic matter stabilization and C sequestration. Soils and humic acids from fo...

  12. Characterization of Natural Organic Matter by FeCl3 Coagulation

    NASA Astrophysics Data System (ADS)

    Cahyonugroho, O. H.; Hidayah, E. N.

    2018-01-01

    Natural organic matter (NOM) is heterogenous mixture of organic compounds that enter the water from various decomposition and metabolic reactions, including animal, plant, domestic and industrial wastes. NOM refers to group of carbon-based compounds that are found in surface water and ground water. The aim of the study is to assess organic matter characteristics in Jagir River as drinking water source and to characterize the organic components that could be removed during coagulation. Coagulation is the common water treatment process can be used to remove NOM with FeCl3 coagulant in various dosage. NOM surrogates, including total organic carbon (TOC), ultraviolet absorbance at 254 nm (UV254) and specific UV absorbance (SUVA) were chosen to assess the organic removal. Results of jar test experiments showed that NOM can be removed about 40% of NOM surrogates with 200 mg/L FeCl3. About 60% removal of total organic fraction, which is mainly humic substances, as detected by size exclusion chromatography (SEC).

  13. Simplified method to assess soil organic matter in landscape and carbon sequestration studies

    NASA Astrophysics Data System (ADS)

    Pallasser, Robert; Minasny, Budiman; McBratney, Alex; de Bruyn, Hank

    2010-05-01

    Soil organic matter (SOM) is composed of a variety of carbon bearing forms which are variably susceptible to degradation, itself a function of soil conditions (moisture, permeability, pH, Eh). Stability and residence time have become key questions relevant to soil carbon storage. Interestingly, organic matter types also differ in terms of their refractory stabilities making thermal analysis potentially an ideal way to resolve and analyse SOM. Elemental analyses of soils are routinely used to provide accurate total carbon determinations for the subsamples in question but cannot yield information about the relative amounts of labile to more stable carbon without involved chemical pre-treatment. Thermogravimetric analyses (TGA) have been commonly used to characterise chemical decomposition and to provide distinctive fingerprints (due to discrete mass changes) for mineral and organic materials. Such discrete changes in mass appear as peaks when registered on a DTGA (differential TGA) plot and correspond with dehydration, denaturing or oxidation events. Soil being a more complex continuum of organic and inorganic substances, many from fermentation reactions and microbial waste, does not have one particular fingerprint. Nonetheless, a number of relevant organic substances have characteristically different but consistent ignition temperatures (Lopez-Capel et. al., 2006; Laird et al., 2008; Xie et. al., 2009) allowing carbon pools to be distinguished thermally. In our studies, oxidative DTGA analyses of soils using a TA 2590 were typified by a bimodal distribution in SOM representing one less stable and one more stable group, a pattern similarly described by Siewert (2004). Current experiments indicate that the relative proportions of these SOM pulses are fairly reproducible but vary depending on soils and sampling depth (i.e. conditions) enabling it as a diagnostic parameter when considering SOM dynamics and humification. In order to compare this property numerically

  14. Precondensed matter - Key to the early solar system

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1978-01-01

    Explicit astrophysical details are developed for the hypothesis that chemical and isotopic anomalies in primitive solar-system samples reflect routine initial chemical conditions within precondensed matter. The central feature of this theory concerns the chemical state of presolar dust, which is regarded as never having been vaporized in the region where the most chemically primitive samples (carbonaceous meteorites) accumulated. It is suggested that the initial chemical state of heavy atoms during meteorite and planetary accumulation was distributed between a refractory-mineral component from high-temperature condensation and a volatile component resulting from cold matter adhering to preexisting grains. Thermal conditions in the solar nebula are considered along with the existence of supernova condensates and other thermal condensates in the interstellar dust. Fractionation into volatile and refractory elements is idealized in terms of four distinct interstellar components, and the fractionated precondensed matter is described.

  15. Preservation of organic matter on Mars by sulfur

    NASA Astrophysics Data System (ADS)

    Eigenbrode, J. L.; Steele, A.; Summons, R. E.; McAdam, A.; Sutter, B.; Franz, H. B.; Freissinet, C.; Millan, M.; Glavin, D. P.; Szopa, C.; Conrad, P. G.; Mahaffy, P. R.

    2016-12-01

    Deltaic-lacustrine mudstones at Pahrump Hills, Gale Crater, Mars yielded a variety of sulfur-containing volatiles upon heating to 500-860°C, as detected by the Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover. The detection of organosulfur compounds comprising thiophenes, dimethylsulfide and thiols by gas chromatography-mass spectrometry and evolved gas analyses, together with aromatic and other hydrocarbon molecules with distributions specific to the sample (i.e., not from the SAM background) indicate that some or all of these organic fragments released at high temperatures are indigenous to the mudstones. The organosulfur compounds are most likely derived from sulfur organics in the sediments. However, there is a possibility that sulfurization of some organic fragments occurred in the oven. On Earth, sulfurization of organic matter is a key process that aids preservation over geological time-scales. This is because it reduces reactive functional groups and adds cross links between small unstable molecules thereby converting them into recalcitrant macromolecules. Sulfurization of organic materials prior to deposition and during early diagenesis may have been a key mechanism responsible for organic matter preservation in the Murray formation mudstones. Sulfur-bearing organics have also been observed in carbonaceous meteorites and there is indication of their presence in the Tissint martian meteorite. A quantitative assessment of organosulfur compounds relative to their non-organic counterparts will be presented for the Murray formation mudstones analyzed by SAM and meteorites analyzed in the laboratory under similar analytical conditions.

  16. Dissolved organic matter in the unsaturated zone: the view from the cave

    NASA Astrophysics Data System (ADS)

    Baker, A.; Duan, W.; Rutlidge, H.; McDonough, L.; Oudone, P.; Meredith, K.; Andersen, M. S.; O'Carroll, D. M.; Coleborn, K.; Treble, P. C.

    2017-12-01

    Soil organic matter content is typically a few percent of the total soil composition. Diffuse recharge can mobilise some of this soil-derived organic matter. While soil pore water dissolved organic matter (DOM) concentrations are up to 100 ppm, the resulting groundwater dissolved organic matter concentration is typically less than 2ppm. Dissolved organic matter transported from the soil can be both biodegraded and sorbed to minerals, and the relative importance of these two processes in the unsaturated zone is poorly understood. Caves in karstified limestone uniquely provide direct access to water percolating from the soil to the groundwater. Cave percolation waters can be analysed for their DOM concentration and character. This provides insights into the extent and type of biological and chemical processing of DOM during transport from the soil to the groundwater. We determine the concentration and characteristics of DOM in cave percolation waters using liquid chromatography (LC-OCD) and optical spectrophotometry (fluorescence and absorbance). We sample DOM from multiple caves in SE Australia (Cathedral Cave, Wellington; South Glory and Harrie Wood Caves, Yarrangobilly), permitting comparison of unsaturated zone DOM properties at different depths (up to 30m below land surface) and different climate zones (montane and temperate). We use caves with long-term hydrological monitoring programs so that DOM in waters of contrasting residence times can be compared. Additionally, we compare these cave percolation water DOM characteristics to those from local and regional groundwater, sampled from nearby wells. Our results will help improve our understanding of how DOM is processed from soil to groundwater, and is also relevant to speleothem scientists interested in using organic matter preserved in speleothems as a paleoclimate or paleoenvironmental proxy.

  17. Sorption of benzimidazole anthelmintics to dissolved organic matter surrogates and sewage sludge.

    PubMed

    Kim, Hyo-Jung; Lee, Dong Soo; Kwon, Jung-Hwan

    2010-06-01

    The sorption coefficients of four rarely studied zwitterionic pharmaceuticals (benzimidazoles: fenbendazole, albendazole, thiabendazole and flubendazole) and four metabolites of fenbendazole to various dissolved organic matter surrogates (humic acid, sodium dodecyl sulfate micelle, hydroxypropyl-beta-cyclodextrin and liposomes made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and sewage sludge) were measured to extend the available sorption coefficients and eventually to evaluate their environmental fate in soil and water environment. For the entire range of dissolved organic matters, the more hydrophobic fenbendazole and albendazole had higher sorption coefficients than thiabendazole and flubendazole, indicating that the traditional hypothesis of hydrophobic interaction holds for zwitterionic benzimidazole anthelmintics. However, the sorption coefficients of a given benzimidazole to selected dissolved organic matters (DOMs) varied within an order of magnitude. The measured K(oc) values decreased in the order of fenbendazole, albendazole, thiabendazole and flubendazole for sewage sludge and hydroxypropyl-beta-cyclodextrin whereas the orders were different for the other DOM surrogates, implying the hydrophilic nature of sewage sludge. This was also supported by the (N+O)/C elemental ratio of the sewage sludge sample used in this study. The correlations between log K(oc) and log K(ow) were weak (r(2)=0.28-0.64) and the magnitude of the sorption coefficients to the hydrophilic organic matters (hydroxypropyl-beta-cyclodextrin and sewage sludge) were similar to or slightly smaller than those for the hydrophobic organic matters (humic acids and liposome). This suggests that specific hydrophilic interactions also play a significant role in the sorption of moderately hydrophobic benzimidazoles to organic matters. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  18. Molecular insights into the microbial formation of marine dissolved organic matter: recalcitrant or labile?

    NASA Astrophysics Data System (ADS)

    Koch, B. P.; Kattner, G.; Witt, M.; Passow, U.

    2014-08-01

    The degradation of marine dissolved organic matter (DOM) is an important control variable in the global carbon cycle. For our understanding of the kinetics of organic matter cycling in the ocean, it is crucial to achieve a mechanistic and molecular understanding of its transformation processes. A long-term microbial experiment was performed to follow the production of non-labile DOM by marine bacteria. Two different glucose concentrations and dissolved algal exudates were used as substrates. We monitored the bacterial abundance, concentrations of dissolved and particulate organic carbon (DOC, POC), nutrients, amino acids and transparent exopolymer particles (TEP) for 2 years. The molecular characterization of extracted DOM was performed by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) after 70 days and after ∼2 years of incubation. Although glucose quickly degraded, a non-labile DOC background (5-9% of the initial DOC) was generated in the glucose incubations. Only 20% of the organic carbon from the algal exudate degraded within the 2 years of incubation. The degradation rates for the non-labile DOC background in the different treatments varied between 1 and 11 μmol DOC L-1 year-1. Transparent exopolymer particles, which are released by microorganisms, were produced during glucose degradation but decreased back to half of the maximum concentration within less than 3 weeks (degradation rate: 25 μg xanthan gum equivalents L-1 d-1) and were below detection in all treatments after 2 years. Additional glucose was added after 2 years to test whether labile substrate can promote the degradation of background DOC (co-metabolism; priming effect). A priming effect was not observed but the glucose addition led to a slight increase of background DOC. The molecular analysis demonstrated that DOM generated during glucose degradation differed appreciably from DOM transformed during the degradation of the algal exudates. Our

  19. Soil Organic Matter Dynamics in the Rothamsted Long-term Experiments

    NASA Astrophysics Data System (ADS)

    MacDonald, A.; Poulton, P.

    2009-04-01

    Soil science research at Rothamsted dates from 1843 when John Bennet Lawes and Joseph Henry Gilbert started the first of a series of what became long-term field experiments. The main object of these experiments was to examine the effect of inorganic and organic fertilisers and manures on crop yield and soil fertility. These "Classical Field Experiments" included studies on winter wheat (Broadbalk 1843), spring barley (Hoos Barley 1852) and permanent grassland (Park Grass 1856). Additional experiments were established in the 20th century to examine the value of ley-arable cropping, including the Highfield and Fosters Ley-arable experiments (1948) and the Woburn Ley-arable experiment (1938). More recently, the effects of incorporating organic manures and cereal straw have been examined. Early results quickly showed the benefits of inorganic N and P fertilisers on crop production, but the effects of contrasting land uses and management practices on soil properties emerged more slowly. Measurements of soil organic carbon (C) and nitrogen (N) in soils taken at intervals from the long-term experiments indicate that the rate of soil organic matter (SOM) accumulation is controlled largely by the balance between the rate of organic matter inputs and its oxidation rate, and that these are strongly influenced by land use and management, soil texture (especially clay content) and climate. A recent examination of soil organic C data from two long-term grassland experiments in the UK (including Park Grass) indicates that any changes observed in soil organic C under long-term grasslands over the past 40 years are more likely to be due to changes in land use and management rather than climate change. Data from the Rothamsted Long-term experiments have been used to develop and test biogeochemical models of C and N dynamics. In particular, the Roth-C model has successfully simulated soil C dynamics in the long-term experiments at Rothamsted and elsewhere. This model uses several

  20. Variation of preserving organic matter bound in interlayer of montmorillonite induced by microbial metabolic process.

    PubMed

    Zhao, Yulian; Dong, Faqin; Dai, Qunwei; Li, Gang; Ma, Jie

    2017-07-25

    This paper aimed to investigate the variation of preserving organic matter bound in the interlayer space of montmorillonite (Mt) induced by a microbe metabolic process. We selected Bacillus pumilus as the common soil native bacteria. The alteration of d 001 value, functional group, and C,N organic matter contents caused by bacteria were analyzed by XRD, FTIR, and elementary analyzer, respectively. XRD results showed that the d 001 value of montmorillonite increased with the concentration decreasing and decreased with the culture time increasing after interacting with bacteria indicating the interlayer space of montmorillonite was connected with the organic matter. The findings of long-term interaction by resetting culture conditions implied that the montmorillonite buffered the organic matter when the nutrition was enough and released again when the nutrition was lacking. The results of the elementary analyzer declared the content of organic matter was according to the d 001 value of montmorillonite and N organic matter which played a major impact. FTIR results confirmed that the Si-O stretching vibrations of Mt were affected by the functional group of organic matter. Our results showed that the montmorillonite under the influence of soil bacteria has a strong buffering capacity for preserving organic matter into the interlayer space in a short-term. It might provide critical implications for understanding the evolution process and the preservation of fertilization which was in the over-fertilization or less-fertilization conditions on farmland.

  1. Microbial and long-range terrestrial contributions of organic matter to Antarctica

    NASA Astrophysics Data System (ADS)

    Antony, R.; Grannas, A. M.; Priest, A. S.; Sleighter, R. L.; Meloth, T.; Hatcher, P.

    2012-12-01

    Composition and cycling of dissolved organic matter in glacial systems is important because of its great significance to global carbon dynamics, snow photochemistry, and air-snow exchange processes. But, due to the trace nature of specific organic components in Polar ice sheets, detecting and studying these species in molecular level detail has been an analytical challenge. Electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) enabled the elucidation of molecular level details of natural organic matter in snow samples collected along a coast to inland transect from the Princesses Elizabeth Land, East Antarctica. Thousands of distinct molecular species comprising of different compound classes were identified providing clues to the nature and sources of organic carbon in Antarctic snow. The major biochemical classes of compounds detected were lignins, tannins, carbohydrates, proteins, amino sugars, lipids, unsaturated hydrocarbons and condensed aromatics. Specifically, lignin molecules comprising up to 50% and compounds derived from algal and microbial biomass comprising up to 45% of the total assigned formulas dominated the organic carbon pool. The identification of a variety of lignin compounds demonstrates substantial input of vascular plant-derived materials to the identified molecular species, presumably from long range atmospheric transport and deposition. The detection of proteins, lipids and amino sugars suggests that a large proportion of the identified supraglacial organic matter likely originates from in situ microbial activity. This corroborates well with the presence of significant numbers of bacteria, picoplankton and microalgae in these samples. These results suggest that organic matter in the supraglacial environments have both a microbial and terrestrial provenance.

  2. Controls on the distribution of fluorescent dissolved organic matter during an under-ice algal bloom in the western Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Mendoza, Wilson G.; Weiss, Elliot L.; Schieber, Brian; Greg Mitchell, B.

    2017-07-01

    In this study we used fluorescence excitation and emission matrix spectroscopy, hydrographic data, and a self-organizing map (SOM) analysis to assess the spatial distribution of labile and refractory fluorescent dissolved organic matter (FDOM) for the Chukchi and Beaufort Seas at the time of a massive under-ice phytoplankton bloom during early summer 2011. Biogeochemical properties were assessed through decomposition of water property classes and sample classification that employed a SOM neural network-based analysis which classified 10 clusters from 269 samples and 17 variables. The terrestrial, humic-like component FDOM (ArC1, 4.98 ± 1.54 Quinine Sulfate Units (QSU)) and protein-like component FDOM (ArC3, 1.63 ± 0.88 QSU) were found to have elevated fluorescence in the Lower Polar Mixed Layer (LPML) (salinity 29.56 ± 0.76). In the LPML water mass, the observed contribution of meteoric water fraction was 17%, relative to a 12% contribution from the sea ice melt fraction. The labile ArC3-protein-like component (2.01 ± 1.92 QSU) was also observed to be elevated in the Pacific Winter Waters mass, where the under-ice algal bloom was observed ( 40-50 m). We interpreted these relationships to indicate that the accumulation and variable distribution of the protein-like component on the shelf could be influenced directly by sea ice melt, transport, and mixing processes and indirectly by the in situ algal bloom and microbial activity. ArC5, corresponding to what is commonly considered marine humic FDOM, indicated a bimodal distribution with high values in both the freshest and saltiest waters. The association of ArC5 with deep, dense salty water is consistent with this component as refractory humic-like FDOM, whereas our evidence of a terrestrial origin challenges this classic paradigm for this component.

  3. 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

  4. The Origin of Organic Matter in the Solar System: Evidence from Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Keller, L. P.; Jacobsen, C.; Wirick, S.

    2001-01-01

    The origin of the organic matter in interplanetary materials has not been established. A variety of mechanisms have been proposed, with two extreme cases being a Fisher-Tropsch type process operating in the gas phase of the solar nebula or a Miller-Urey type process, which requires interaction with an aqueous fluid, presumably occurring on an asteroid. In the Fisher-Tropsch case, we might expect similar organic matter in hydrated and anhydrous interplanetary materials. However, aqueous alteration is required in the case of the Miller-Urey process, and we would expect to see organic matter preferentially in interplanetary materials that exhibit evidence of aqueous activity, such as the presence of hydrated silicates. The types and abundance of organic matter in meteorites have been used as an indicator of the origin of organic matter in the Solar System. Indigenous complex organic matter, including amino acids, has been found in hydrated carbonaceous chondrite meteorites, such as Murchison. Much lower amounts of complex organic matter, possibly only terrestrial contamination, have been found in anhydrous carbonaceous chondrite meteorites, such as Allende, that contain most of their carbon in elemental form. These results seem to favor production of the bulk of the organic matter in the Solar System by aqueous processing on parent bodies such as asteroids, a Miller-Urey process. However, the hydrated carbonaceous chondrite meteorites have approximately solar abundances of the moderately volatile elements, while all anhydrous carbonaceous chondrite meteorites have significantly lower contents of these moderately volatile elements. Two mechanisms, incomplete condensation or evaporation, both of which involve processing at approx. 1200 C, have been suggested to explain the lower content of the moderately volatile elements in all anhydrous meteorites. Additional information is contained in the original extended abstract.

  5. Anthropogenic N deposition increases soil organic matter accumulation without altering its biochemical composition.

    PubMed

    Zak, Donald R; Freedman, Zachary B; Upchurch, Rima A; Steffens, Markus; Kögel-Knabner, Ingrid

    2017-02-01

    Accumulating evidence indicates that future rates of atmospheric N deposition have the potential to increase soil C storage by reducing the decay of plant litter and soil organic matter (SOM). Although the microbial mechanism underlying this response is not well understood, a decline in decay could alter the amount, as well as biochemical composition of SOM. Here, we used size-density fractionation and solid-state 13 C-NMR spectroscopy to explore the extent to which declines in microbial decay in a long-term (ca. 20 yrs.) N deposition experiment have altered the biochemical composition of forest floor, bulk mineral soil, as well as free and occluded particulate organic matter. Significant amounts of organic matter have accumulated in occluded particulate organic matter (~20%; oPOM); however, experimental N deposition had not altered the abundance of carboxyl, aryl, alkyl, or O/N-alkyl C in forest floor, bulk mineral soil, or any soil fraction. These observations suggest that biochemically equivalent organic matter has accumulated in oPOM at a greater rate under experimental N deposition, relative to the ambient treatment. Although we do not understand the process by which experimental N deposition has fostered the occlusion of organic matter by mineral soil particles, our results highlight the importance of interactions among the products of microbial decay and the chemical and physical properties of silt and clay particles that occlude organic matter from microbial attack. Because oPOM can reside in soils for decades to centuries, organic matter accumulating under future rates of anthropogenic N deposition could remain in soil for long periods of time. If temperate forest soils in the Northern Hemisphere respond like those in our experiment, then unabated deposition of anthropogenic N from the atmosphere has the potential to foster greater soil C storage, especially in fine-texture forest soils. © 2016 John Wiley & Sons Ltd.

  6. Comprehensive characterization of atmospheric organic matter in Fresno, California fog water

    USGS Publications Warehouse

    Herckes, P.; Leenheer, J.A.; Collett, J.L.

    2007-01-01

    Fogwater collected during winter in Fresno (CA) was characterized by isolating several distinct fractions and characterizing them by infrared and nuclear magnetic resonance (NMR) spectroscopy. More than 80% of the organic matter in the fogwater was recovered and characterized. The most abundant isolated fractions were those comprised of volatile acids (24% of isolated carbon) and hydrophilic acids plus neutrals (28%). Volatile acids, including formic and acetic acid, have been previously identified as among the most abundant individual species in fogwater. Recovered hydrophobic acids exhibited some properties similar to aquatic fulvic acids. An insoluble particulate organic matter fraction contained a substantial amount of biological material, while hydrophilic and transphilic fractions also contained material suggestive of biotic origin. Together, these fractions illustrate the important contribution biological sources make to organic matter in atmospheric fog droplets. The fogwater also was notable for containing a large amount of organic nitrogen present in a variety of species, including amines, nitrate esters, peptides, and nitroso compounds. ?? 2007 American Chemical Society.

  7. Comprehensive characterization of atmospheric organic matter in Fresno, California fog water.

    PubMed

    Herckes, Pierre; Leenheer, Jerry A; Collett, Jeffrey L

    2007-01-15

    Fogwater collected during winter in Fresno (CA) was characterized by isolating several distinct fractions and characterizing them by infrared and nuclear magnetic resonance (NMR) spectroscopy. More than 80% of the organic matter in the fogwater was recovered and characterized. The most abundant isolated fractions were those comprised of volatile acids (24% of isolated carbon) and hydrophilic acids plus neutrals (28%). Volatile acids, including formic and acetic acid, have been previously identified as among the most abundant individual species in fogwater. Recovered hydrophobic acids exhibited some properties similar to aquatic fulvic acids. An insoluble particulate organic matter fraction contained a substantial amount of biological material, while hydrophilic and transphilic fractions also contained material suggestive of biotic origin. Together, these fractions illustrate the important contribution biological sources make to organic matter in atmospheric fog droplets. The fogwater also was notable for containing a large amount of organic nitrogen present in a variety of species, including amines, nitrate esters, peptides, and nitroso compounds.

  8. SOIL NITROGEN TRANSFORMATIONS AND ROLE OF LIGHT FRACTION ORGANIC MATTER IN FOREST SOILS

    EPA Science Inventory

    Depletion of soil organic matter through cultivation may alter substrate availability for microbes, altering the dynamic balance between nitrogen (N) immobilization and mineralization. Soil light fraction (LF) organic matter is an active pool that decreases upon cultivation, and...

  9. Turnover of intra- and extra-aggregate organic matter at the silt-size scale

    Treesearch

    I. Virto; C. Moni; C. Swanston; C. Chenu

    2010-01-01

    Temperate silty soils are especially sensitive to organic matter losses associated to some agricultural management systems. Long-term preservation of organic C in these soils has been demonstrated to occur mainly in the silt- and clay-size fractions, although our knowledge about the mechanisms through which it happens remains unclear. Although organic matter in such...

  10. Pharmacotherapy for Refractory and Super-Refractory Status Epilepticus in Adults.

    PubMed

    Holtkamp, Martin

    2018-03-01

    Patients with prolonged seizures that do not respond to intravenous benzodiazepines and a second-line anticonvulsant suffer from refractory status epilepticus and those with seizures that do not respond to continuous intravenous anesthetic anticonvulsants suffer from super-refractory status epilepticus. Both conditions are associated with significant morbidity and mortality. A strict pharmacological treatment regimen is urgently required, but the level of evidence for the available drugs is very low. Refractory complex focal status epilepticus generally does not require anesthetics, but all intravenous non-anesthetizing anticonvulsants may be used. Most descriptive data are available for levetiracetam, phenytoin and valproate. Refractory generalized convulsive status epilepticus is a life-threatening emergency, and long-term clinical consequences are eminent. Administration of intravenous anesthetics is mandatory, and drugs acting at the inhibitory gamma-aminobutyric acid (GABA) A receptor such as midazolam, propofol and thiopental/pentobarbital are recommended without preference for one of those. One in five patients with anesthetic treatment does not respond and has super-refractory status epilepticus. With sustained seizure activity, excitatory N-methyl-d-aspartate (NMDA) receptors are increasingly expressed post-synaptically. Ketamine is an antagonist at this receptor and may prove efficient in some patients at later stages. Neurosteroids such as allopregnanolone increase sensitivity at GABA A receptors; a Phase 1/2 trial demonstrated safety and tolerability, but randomized controlled data failed to demonstrate efficacy. Adjunct ketogenic diet may contribute to termination of difficult-to-treat status epilepticus. Randomized controlled trials are needed to increase evidence for treatment of refractory and super-refractory status epilepticus, but there are multiple obstacles for realization. Hitherto, prospective multicenter registries for pharmacological

  11. Treatment of Refractory and Super-refractory Status Epilepticus.

    PubMed

    Rai, Samhitha; Drislane, Frank W

    2018-06-19

    Refractory and super-refractory status epilepticus (SE) are serious illnesses with a high risk of morbidity and even fatality. In the setting of refractory generalized convulsive SE (GCSE), there is ample justification to use continuous infusions of highly sedating medications-usually midazolam, pentobarbital, or propofol. Each of these medications has advantages and disadvantages, and the particulars of their use remain controversial. Continuous EEG monitoring is crucial in guiding the management of these critically ill patients: in diagnosis, in detecting relapse, and in adjusting medications. Forms of SE other than GCSE (and its continuation in a "subtle" or nonconvulsive form) should usually be treated far less aggressively, often with nonsedating anti-seizure drugs (ASDs). Management of "non-classic" NCSE in ICUs is very complicated and controversial, and some cases may require aggressive treatment. One of the largest problems in refractory SE (RSE) treatment is withdrawing coma-inducing drugs, as the prolonged ICU courses they prompt often lead to additional complications. In drug withdrawal after control of convulsive SE, nonsedating ASDs can assist; medical management is crucial; and some brief seizures may have to be tolerated. For the most refractory of cases, immunotherapy, ketamine, ketogenic diet, and focal surgery are among several newer or less standard treatments that can be considered. The morbidity and mortality of RSE is substantial, but many patients survive and even return to normal function, so RSE should be treated promptly and as aggressively as the individual patient and type of SE indicate.

  12. A multiproxy approach to understanding the "enhanced" flux of organic matter through the oxygen-deficient waters of the Arabian Sea

    NASA Astrophysics Data System (ADS)

    Keil, Richard G.; Neibauer, Jacquelyn A.; Biladeau, Christina; van der Elst, Kelsey; Devol, Allan H.

    2016-04-01

    Free-drifting sediment net traps were deployed 14 times at depths between 80 and 500 m for 1-3 days each during the late monsoon-intermonsoon transition in the central Arabian Sea. Two locations (19.5 and 15.5° N) were within the permanently oxygen-deficient zone (ODZ), and a third (11° N) had a shallow and thin oxygen minimum. The secondary nitrite maximum, which serves as a tracer of the ODZ, thinned from ˜ 250 m thick at stations 19.5 and 15.5° N to ˜ 50 m thick at station 11° N. Overall, organic carbon fluxes ranged from 13.2 g m2 yr-1 at 80 m to a minimum of 1.1 g m2 yr-1 at 500 m. Fluxes at the more oxygenated 11° N station attenuate faster than within the permanent ODZ. Martin curve attenuation coefficients for 19.5 and 15.5° N are respectively 0.59 and 0.63 and for 11° N it is 0.98. At least six potential mechanisms might explain why particles sinking through the ODZ are more effectively transferred to depth: (M1) oxygen effects, (M2) microbial loop efficiencies and chemoautotrophy, (M3) changes in zooplankton dynamics, (M4) additions of ballast that might sorb and protect organic matter from decay (M4a) or change sinking speeds (M4b), (M5) inputs of refractory organic matter and (M6) temperature effects. These mechanisms are intertwined, and they were explored using a combination of mineral (XPS) and organic matter characterizations of the sinking material, shipboard incubation experiments, and evaluations of existing literature. Direct evidence was found supporting an oxygen effect and/or changes in the efficiency of the microbial loop including the addition of chemoautotrophic carbon to the sinking flux in the upper 500 m. Less direct evidence was found for the other potential mechanisms. A simple conceptual model consistent with our and other recent data suggests that the upper ODZ microbial community determines the initial flux attenuation, and that zooplankton and sinking speed become more important deeper in the water column. The exact

  13. A multiproxy approach to understanding the "enhanced" flux of organic matter through the oxygen deficient waters of the Arabian Sea

    NASA Astrophysics Data System (ADS)

    Keil, R. G.; Neibauer, J.; Biladeau, C.; van der Elst, K.; Devol, A. H.

    2015-10-01

    Free-drifting sediment net traps were deployed 14 times at depths between 80 and 500 m for 1-3 days each during the late monsoon/intermonsoon transition in the central Arabian Sea. Two locations (19.5 and 15.5° N) were within the permanently oxygen deficient zone, and a third (11° N) had a shallow and thin oxygen minimum. The secondary nitrite maximum, which serves as a tracer of the oxygen deficient zone (ODZ) zone, thinned from ∼ 250 m thick at stations 19.5 and 15.5° N to ∼ 50 m thick at station 11° N. Overall, organic carbon fluxes ranged from 13.2 g m2 yr-1 at 80 m to a minimum of 1.1 g m2 yr-1 at 500 m. Fluxes at the more oxygenated 11° N station attenuate faster than within the permanent ODZ. Martin curve attenuation coefficients for 19.5 and 15.5° N are 0.59 and 0.63 and for 11° N it is 0.98. At least six potential mechanisms might explain why sinking particles sinking through the ODZ are more effectively transferred to depth; (M1) oxygen effects, (M2) microbial loop efficiencies and chemoautotrophy, (M3) changes in zooplankton dynamics, (M4) additions of ballast that might sorb and protect organic matter from decay, (M5) inputs of refractory organic matter, and (M6) changes in sinking speeds. These mechanisms are intertwined, and were explored using a combination of mineral (XPS) and organic matter characterizations of the sinking material and ship-board incubation experiments. Evidence was found supporting an oxygen effect and/or changes in the efficiency of the microbial loop including the addition of chemoautotrophic carbon to the sinking flux in the upper 500 m. Less evidence was found for the other potential mechanisms. A simple conceptual model consistent with our and other recent data suggests that the upper ODZ microbial community determines the initial flux attenuation, and that deeper in the water column zooplankton and sinking speed become more important. The exact interplay between the various mechanisms remains to be further

  14. Molecular characterization of macrophyte-derived dissolved organic matters and their implications for lakes

    USDA-ARS?s Scientific Manuscript database

    Chemical properties of whole organic matter (OM) and its dissolved organic matter (DOM) fraction from six dominant macrophytes in Lake Dianchi were comparatively characterized, and their environmental implications were discussed. Significant differences in chemical composition of the OM samples were...

  15. Organic Matter Decomposition following Harvesting and Site Preparation of a Forested Wetland

    Treesearch

    Carl C. Trettin; M. Davidian; M.F. Jurgensen; R. Lea

    1996-01-01

    Organic matter accumulation is an important process that affects ecosystem function in many northern wetlands. The cotton strip assay (CSA)was used to measure the effect of harvesting and two different site preparation treatments, bedding and trenching, on organic matter decomposition in a forested wetland. A Latin square experimental design was used to determine the...

  16. Explaining the apparent resiliency of loblolly pine plantation to organic matter removal

    Treesearch

    Jeff A. Hatten; Eric B. Surce; Zakiya Leggett; Jason Mack; Scott D. Roberts; Janet Dewey; Brian Strahm

    2015-01-01

    We utilized 15-year measurements from an organic matter manipulation experiment in a loblolly pine plantation in the Upper Coastal Plain of Alabama to examine the apparent resiliency of a loblolly pine stand to organic matter removal. Treatments included complete removal of harvest residues and forest floor (removed), doubling of harvest residues and forest floor (...

  17. The surface area of soil organic matter

    USGS Publications Warehouse

    Chiou, C.T.; Lee, J.-F.; Boyd, S.A.

    1990-01-01

    The previously reported surface area for soil organic matter (SOM) of 560-800 m2/g as determined by the ethylene glycol (EG) retention method was reexamined by the standard BET method based on nitrogen adsorption at liquid nitrogen temperature. Test samples consisted of two high organic content soils, a freeze-dried soil humic acid, and an oven-dried soil humic acid. The measured BET areas for these samples were less than 1 m2/g, except for the freeze-dried humic acid. The results suggest that surface adsorption of nonionic organic compounds by SOM is practically insignificant in comparison to uptake by partition. The discrepancy between the surface areas of SOM obtained by BET and EG methods was explained in terms of the 'free surface area' and the 'apparent surface area' associated with these measurements.The previously reported surface area for soil organic matter (SOM) of 560-800 m2/g as determined by the ethylene glycol (EG) retention method was reexamined by the standard BET method based on nitrogen adsorption at liquid nitrogen temperature. Test samples consisted of two high organic content soils, a freeze-dried soil humic acid, and an oven-dried soil humic acid. The measured BET areas for these samples were less than 1 m2/g, except for the freeze-dried humic acid. The results suggest that surface adsorption of nonionic organic compounds by SOM is practically insignificant in comparison to uptake by partition. The discrepancy between the surface areas of SOM obtained by BET and EG methods was explained in terms of the 'free surface area' and the 'apparent surface area' associated with these measurements.

  18. Rare earth elements and neodymium isotopes in sedimentary organic matter

    NASA Astrophysics Data System (ADS)

    Freslon, Nicolas; Bayon, Germain; Toucanne, Samuel; Bermell, Sylvain; Bollinger, Claire; Chéron, Sandrine; Etoubleau, Joel; Germain, Yoan; Khripounoff, Alexis; Ponzevera, Emmanuel; Rouget, Marie-Laure

    2014-09-01

    We report rare earth element (REE) and neodymium (Nd) isotope data for the organic fraction of sediments collected from various depositional environments, i.e. rivers (n = 25), estuaries (n = 18), open-ocean settings (n = 15), and cold seeps (n = 12). Sedimentary organic matter (SOM) was extracted using a mixed hydrogen peroxide/nitric acid solution (20%-H2O2-0.02 M-HNO3), after removal of carbonate and oxy-hydroxide phases with dilute hydrochloric acid (0.25 M-HCl). A series of experimental tests indicate that extraction of sedimentary organic compounds using H2O2 may be complicated occasionally by partial dissolution of sulphide minerals and residual carbonates. However, this contamination is expected to be minor for REE because measured concentrations in H2O2 leachates are about two-orders of magnitude higher than in the above mentioned phases. The mean REE concentrations determined in the H2O2 leachates for samples from rivers, estuaries, coastal seas and open-ocean settings yield relatively similar levels, with ΣREE = 109 ± 86 ppm (mean ± s; n = 58). The organic fractions leached from cold seep sediments display even higher concentration levels (285 ± 150 ppm; mean ± s; n = 12). The H2O2 leachates for most sediments exhibit remarkably similar shale-normalized REE patterns, all characterized by a mid-REE enrichment compared to the other REE. This suggests that the distribution of REE in leached sedimentary organic phases is controlled primarily by biogeochemical processes, rather than by the composition of the source from which they derive (e.g. pore, river or sea-water). The Nd isotopic compositions for organic phases leached from river sediments are very similar to those for the corresponding detrital fractions. In contrast, the SOM extracted from marine sediments display εNd values that typically range between the εNd signatures for terrestrial organic matter (inferred from the analysis of the sedimentary detrital fractions) and marine organic matter

  19. Identification of sources and seasonal variability of organic matter in Lake Sihwa and surrounding inland creeks, South Korea.

    PubMed

    Lee, Yeonjung; Hong, Seongjin; Kim, Min-Seob; Kim, Dahae; Choi, Bo-Hyung; Hur, Jin; Khim, Jong Seong; Shin, Kyung-Hoon

    2017-06-01

    Coastal areas are subjected to significant allochthonous organic matter deposits from surrounding areas; however, limited information is available on the source and delivery of this organic matter. In this study, to assess seasonal changes in the sources of organic matter in Lake Sihwa (Korea), biodegradability, fluorescence property, and stable isotopic compositions (carbon, nitrogen, and sulfur) of the organic matter were determined. Water samples were collected from the inner lake (n = 9) and inland creeks (n = 10) in five separate events, from November 2012 to October 2013. Organic matter originating from rural, urban, and industrial areas was examined as the potential sources. The organic matter contents and biodegradability in the industrial area were the highest, whereas low concentrations and poor biodegradability of organic matter were found in the rural area, and moderate properties were observed in the urban area. In Lake Sihwa, a large concentration of total organic matter and enhanced biodegradability were observed during March and August. However, main source of organic matter differed between the sampling events. The largest contribution of organic matter, deriving from marine phytoplankton, was found in March. On the other hand, in August, the organic matter originating from the industrial area, which is characterized by high levels of heavy metals and persistent organic pollutants, was significantly increased. Our results could be useful to enhance the management of water bodies aimed at reducing the organic matter concentrations and improving the water quality of Lake Sihwa, and even that of the Yellow Sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Final Technical Report: Mercury Release from Organic Matter (OM) and OM-Coated Mineral Surfaces

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

    Nagy, Kathryn L.

    2015-08-18

    Chemical reactions between mercury, a neurotoxin, and sulfur, an essential nutrient, in the environment control to a large extent the distribution and amount of mercury available for uptake by living organisms. The largest reservoir of sulfur in soils is in living, decaying, and dissolved natural organic matter. The decaying and dissolved organic matter can also coat the surfaces of minerals in the soil. Mercury (as a divalent cation) can bind to the sulfur species in the organic matter as well as to the bare mineral surfaces, but the extent of binding and release of this mercury is not well understood.more » The goals of the research were to investigate fundamental relationships among mercury, natural organic matter, and selected minerals to better understand specifically the fate and transport of mercury in contaminated soils downstream from the Y-12 plant along East Fork Poplar Creek, Tennessee, and more generally in any contaminated soil. The research focused on (1) experiments to quantify the uptake and release of mercury from two clay minerals in the soil, kaolinite and vermiculite, in the presence and absence of dissolved organic matter; (2) release of mercury from cinnabar under oxic and anoxic conditions; (3) characterization of the forms of mercury in the soil using synchrotron X-ray absorption spectroscopic techniques; and, (4) determination of molecular forms of mercury in the presence of natural organic matter. We also leveraged funding from the National Science Foundation to (5) evaluate published approaches for determining sulfur speciation in natural organic matter by fitting X-ray Absorption Near Edge Structure (XANES) spectra obtained at the sulfur K-edge and apply optimized fitting schemes to new measurements of sulfur speciation in a suite of dissolved organic matter samples from the International Humic Substances Society. Lastly, in collaboration with researchers at the University of Colorado and the U.S. Geological Survey in Boulder

  1. High-molecular-weight organic matter in the particles of comet 67P/Churyumov-Gerasimenko.

    PubMed

    Fray, Nicolas; Bardyn, Anaïs; Cottin, Hervé; Altwegg, Kathrin; Baklouti, Donia; Briois, Christelle; Colangeli, Luigi; Engrand, Cécile; Fischer, Henning; Glasmachers, Albrecht; Grün, Eberhard; Haerendel, Gerhard; Henkel, Hartmut; Höfner, Herwig; Hornung, Klaus; Jessberger, Elmar K; Koch, Andreas; Krüger, Harald; Langevin, Yves; Lehto, Harry; Lehto, Kirsi; Le Roy, Léna; Merouane, Sihane; Modica, Paola; Orthous-Daunay, François-Régis; Paquette, John; Raulin, François; Rynö, Jouni; Schulz, Rita; Silén, Johan; Siljeström, Sandra; Steiger, Wolfgang; Stenzel, Oliver; Stephan, Thomas; Thirkell, Laurent; Thomas, Roger; Torkar, Klaus; Varmuza, Kurt; Wanczek, Karl-Peter; Zaprudin, Boris; Kissel, Jochen; Hilchenbach, Martin

    2016-10-06

    The presence of solid carbonaceous matter in cometary dust was established by the detection of elements such as carbon, hydrogen, oxygen and nitrogen in particles from comet 1P/Halley. Such matter is generally thought to have originated in the interstellar medium, but it might have formed in the solar nebula-the cloud of gas and dust that was left over after the Sun formed. This solid carbonaceous material cannot be observed from Earth, so it has eluded unambiguous characterization. Many gaseous organic molecules, however, have been observed; they come mostly from the sublimation of ices at the surface or in the subsurface of cometary nuclei. These ices could have been formed from material inherited from the interstellar medium that suffered little processing in the solar nebula. Here we report the in situ detection of solid organic matter in the dust particles emitted by comet 67P/Churyumov-Gerasimenko; the carbon in this organic material is bound in very large macromolecular compounds, analogous to the insoluble organic matter found in the carbonaceous chondrite meteorites. The organic matter in meteorites might have formed in the interstellar medium and/or the solar nebula, but was almost certainly modified in the meteorites' parent bodies. We conclude that the observed cometary carbonaceous solid matter could have the same origin as the meteoritic insoluble organic matter, but suffered less modification before and/or after being incorporated into the comet.

  2. Soil Quality of Restinga Forest: Organic Matter and Aluminum Saturation

    NASA Astrophysics Data System (ADS)

    Rodrigues Almeida Filho, Jasse; Casagrande, José Carlos; Martins Bonilha, Rodolfo; Soares, Marcio Roberto; Silva, Luiz Gabriel; Colato, Alexandre

    2013-04-01

    The restinga vegetation (sand coastal plain vegetation) consists of a mosaic of plant communities, which are defined by the characteristics of the substrates, resulting from the type and age of the depositional processes. This mosaic complex of vegetation types comprises restinga forest in advanced (high restinga) and medium regeneration stages (low restinga), each with particular differentiating vegetation characteristics. Of all ecosystems of the Atlantic Forest, restinga is the most fragile and susceptible to anthropic disturbances. The purpose of this study was evaluating the organic matter and aluminum saturation effects on soil quality index (SQI). Two locations were studied: State Park of the Serra do Mar, Picinguaba, in the city of Ubatuba (23°20' e 23°22' S / 44°48' e 44°52' W), and State Park of Cardoso Island in the city of Cananéia (25°03'05" e 25°18'18" S / 47°53'48" e 48° 05'42" W). The soil samples were collect at a depth of 0-10 cm, where concentrate 70% of vegetation root system. Was studied an additive model to evaluate soil quality index. The shallow root system development occurs due to low calcium levels, whose disability limits their development, but also can reflect on delay, restriction or even in the failure of the development vegetation. The organic matter is kept in the soil restinga ecosystem by high acidity, which reduces the decomposition of soil organic matter, which is very poor in nutrients. The base saturation, less than 10, was low due to low amounts of Na, K, Ca and Mg, indicating low nutritional reserve into the soil, due to very high rainfall and sandy texture, resulting in high saturation values for aluminum. Considering the critical threshold to 3% organic matter and for aluminum saturation to 40%, the IQS ranged from 0.95 to 0.1 as increased aluminum saturation and decreased the soil organic matter, indicating the main limitation to the growth of plants in this type of soil, when deforested.

  3. The composition and degradability of upland dissolved organic matter

    NASA Astrophysics Data System (ADS)

    Moody, Catherine; Worrall, Fred; Clay, Gareth

    2016-04-01

    In order to assess controls on the degradability of DOM in stream water, samples of dissolved organic matter (DOM) and particulate organic matter (POM) were collected every month for a period of 24 months from an upland, peat-covered catchment in northern England. Each month the degradability of the DOM was assessed by exposing river water to light for up to 24 hours, and the change in the dissolved organic carbon (DOC) concentration in the water was measured. To provide context for the analysis of DOM and its degradability, samples of peat, vegetation, and litter were also taken from the same catchment and analysed. The organic matter samples were analysed by several methods including: elemental analysis (CHN and O), bomb calorimetry, thermogravimetric analysis, pyrolysis GC/MS, ICP-OES, stable isotope analysis (13C and 15N) and 13C solid state nuclear magnetic resonance (NMR). The water samples were analysed for pH, conductivity, absorbance at 400nm, anions, cations, particulate organic carbon (POC) and DOC concentrations. River flow conditions and meteorology were also recorded at the site and included in the analysis of the composition and degradability of DOM. The results of multiple regression models showed that the rates of DOC degradation were affected by the N-alkyl, O-alkyl, aldehyde and aromatic relative intensities, gross heat, OR and C:N. Of these, the N-alkyl relative intensity had the greatest influence, and this in turn was found to be dependent on the rainfall and soil temperature in the week before sampling.

  4. Characterizing Variability In Ohio River Natural Organic Matter

    EPA Science Inventory

    Surface water contains natural organic matter (NOM) which reacts with disinfectants creating disinfection byproducts (DBPs), some of which are USEPA regulated contaminants. Characterizing NOM can provide important insight on DBP formation and water treatment process adaptation t...

  5. Photodegradation of Pyrogenic Dissolved Organic Matter (Biochar Leachates)

    NASA Astrophysics Data System (ADS)

    Bostick, K. W.; Zimmerman, A. R.; Hatcher, P.; Mitra, S.; Wozniak, A. S.

    2017-12-01

    A large portion of soil organic matter has been suggested to be pyrogenic (e.g., charred biomass or soot). While pyrogenic organic matter has been regarded as relatively stable in the environment, significant losses of pyrogenic organic carbon can occur via degradation and solubilization. Pyrogenic dissolved organic matter (py-DOM) could be an important intermediate in global C cycling, however its geochemical fate is still unknown. In the current study, the mineralization and transformation of py-DOM were explored through a series of photodegradation experiments. A biochar prepared by pyrolyzing oak wood at 400 °C was leached for a period of 48 hours. This leachate was exposed to light simulating the irradiance and spectra of natural sunlight from 295 to 365 nm. Photodegraded leachate was subsampled during a period of 20 days and analyzed for TOC, DIC and TN. Additionally, solid phase (PPL) extracts of leachate DOM were oxidized in hot nitric acid and analyzed via HPLC for benzenepolycarboxylic acids (BPCAs). In previous studies, the proportion of aromatically condensed py-DOM (as indicated carboxyl substitution in BPCA) in biochar leachates was found to increase with parent char pyrolysis temperature. Thus, to explore the influence of py-DOM type on photodegradation, losses of C, N, and condensed aromatic C were examined in leachates of an oak biochar thermal series (pyrolyzed at 400, 525, 650 °C). The resulting rates of photo-degradative losses in py-C and condensed aromatics in these leachates can be used to estimate the stability/longevity of py-DOM in aquatic systems, potential for py-DOM export from terrestrial systems, and negative effects to aquatic ecosystems.

  6. Molecular fractionation of dissolved organic matter with metal salts.

    PubMed

    Riedel, Thomas; Biester, Harald; Dittmar, Thorsten

    2012-04-17

    Coagulation of dissolved organic matter (DOM) by hydrolyzing metals is an important environmental process with particular relevance, e.g., for the cycling of organic matter in metal-rich aquatic systems or the flocculation of organic matter in wastewater treatment plants. Often, a nonremovable fraction of DOM remains in solution even at low DOM/metal ratios. Because coagulation by metals results from interactions with functional groups, we hypothesize that noncoagulating fractions have a distinct molecular composition. To test the hypothesis, we analyzed peat-derived dissolved organic matter remaining in solution after mixing with salts of Ca, Al, and Fe using 15 T Electrospray Ionization Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FT-ICR-MS). Addition of metals resulted in a net removal of DOM. Also a reduction of molecular diversity was observed, as the number of peaks from the ESI-FT-ICR-MS spectra decreased. At DOM/metal ratios of ∼9 Ca did not show any preference for distinct molecular fractions, while Fe and Al removed preferentially the most oxidized compounds (O/C ratio >0.4) of the peat leachate. Lowering DOM/metal ratios to ∼1 resulted in further removal of less oxidized as well as more aromatic compounds ("black carbon"). Molecular composition in the residual solution after coagulation was more saturated, less polar, and less oxidized compared to the original peat leachate and exhibited a surprising similarity with DOM of marine origin. By identifying more than 9200 molecular formulas we can show that structural properties (saturation and aromaticity) and oxygen content of individual DOM molecules play an important role in coagulation with metals. We conclude that polyvalent cations not only alter the net mobility but also the very molecular composition of DOM in aquatic environments.

  7. Molecular weight distribution of organic matter by ozonation and biofiltration.

    PubMed

    Lin, Yen-Hui

    2012-01-01

    Molecular weight (MW) distribution of organic matter by ozonation and biofiltration was evaluated using gel chromatography. The MW distribution of organic matter by Sephadex G-25 was observed from groups 2 (MW = 1,029-7,031 g/mol) and 3 (MW = 303-1,029 g/mol) shifted to groups 2, 3 and 4 (MW < 303 g/mol) under ozone doses of 0.1 and 0.4 mg O₃/mg total organic carbon (TOC). The shift in MW increases as ozone dosage increases. Biofiltration effectively degraded the organic molecule of group 2; however, the biofiltration only slightly degraded the organic molecule of group 4. Increased ozone dose destroyed functional groups C═C in phenolic and C-O in alcoholic compounds and increased UV-insensitive biodegradable organic carbon for subsequent biofiltration. Biofiltration effectively degraded organic compounds of alcohols and alkenes at an ozone dose of 0.1 mg O₃/mg TOC. Experimental approaches in this study can be applied to evaluate and diagnose the function of a full-scale process combining ozonation and biofiltration in drinking water treatment plants.

  8. Mangroves, a major source of dissolved organic carbon to the oceans

    NASA Astrophysics Data System (ADS)

    Dittmar, Thorsten; Hertkorn, Norbert; Kattner, Gerhard; Lara, RubéN. J.

    2006-03-01

    Organic matter, which is dissolved in low concentrations in the vast waters of the oceans, contains a total amount of carbon similar to atmospheric carbon dioxide. To understand global biogeochemical cycles, it is crucial to quantify the sources of marine dissolved organic carbon (DOC). We investigated the impact of mangroves, the dominant intertidal vegetation of the tropics, on marine DOC inventories. Stable carbon isotopes and proton nuclear magnetic resonance spectroscopy showed that mangroves are the main source of terrigenous DOC in the open ocean off northern Brazil. Sunlight efficiently destroyed aromatic molecules during transport offshore, removing about one third of mangrove-derived DOC. The remainder was refractory and may thus be distributed over the oceans. On a global scale, we estimate that mangroves account for >10% of the terrestrially derived, refractory DOC transported to the ocean, while they cover only <0.1% of the continents' surface.

  9. Characterisation of the biodegradability of post-treated digestates via the chemical accessibility and complexity of organic matter.

    PubMed

    Maynaud, Géraldine; Druilhe, Céline; Daumoin, Mylène; Jimenez, Julie; Patureau, Dominique; Torrijos, Michel; Pourcher, Anne-Marie; Wéry, Nathalie

    2017-05-01

    The stability of digestate organic matter is a key parameter for its use in agriculture. Here, the organic matter stability was compared between 14 post-treated digestates and the relationship between organic matter complexity and biodegradability was highlighted. Respirometric activity and CH 4 yields in batch tests showed a positive linear correlation between both types of biodegradability (R 2 =0.8). The accessibility and complexity of organic matter were assessed using chemical extractions combined with fluorescence spectroscopy, and biodegradability was mostly anti-correlated with complexity of organic matter. Post-treatments presented a significant effect on the biodegradability and complexity of organic matter. Biodegradability was low for composted digestates which comprised slowly accessible complex molecules. Inversely, solid fractions obtained after phase separation contained a substantial part of remaining biodegradable organic matter with a significant easily accessible fraction comprising simpler molecules. Understanding the effect of post-treatment on the biodegradability of digestates should help to optimize their valorization. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Similarities in Photodegradation of Cyanobacteria-Derived and Marine Fluorescent Dissolved Organic Matter

    NASA Astrophysics Data System (ADS)

    Ianiri, H. L.; Timko, S.; Gonsior, M.

    2016-02-01

    Marine dissolved organic matter (DOM) is one of the largest reduced carbon reservoirs on Earth, yet we only have a limited understanding of its production, cycling, degradation, and overall structure. It was previously believed that a significant portion of refractory dissolved organic carbon (RDOC) in the ocean was derived from terrestrial sources, however recent studies indicated that the majority of marine DOM might be produced in situ by marine biota. Previous research has found that terrestrial and microbial DOM fluorescent signatures are similar, complicating the identification of the origins of marine fluorescent DOM (FDOM). However, photodegradation kinetics of terrestrial and microbial-derived DOM are expected to be different due to their assumed different chemical compositions. In this study we analyzed for the first time the photodegradation kinetics of microbial-derived DOM originating from different cyanobacteria strains. Cyanobacterial-derived DOM were exposed to simulated sunlight for a total of 20 hours while recording excitation emission matrix (EEM) fluorescence every twenty minutes to observe the photodegradation of this specific FDOM. Parallel Factor Analysis (PARAFAC) was applied to deconvolute the EEM matrices into six separate components. The photodegradation kinetics was then calculated for each component and compared with previously obtained photodegradation data of marine and terrestrial FDOM. This six component PARAFAC model was similar to those generated from open ocean data and global DOM data sets. The "humic-like" FDOM was also found in cyanobacteria FDOM and showed similar fluorescence intensities and percent fluorescence loss when compared to marine DOM. The degradation kinetics of the "humic-like" component of microbial-derived DOM was faster than that of terrestrial-derived DOM, and marine FDOM samples showed degradation kinetics more similar to microbial-derived FDOM. This indicates marine FDOM is more similar in chemical

  11. Organic matter sources and rehabilitation of the Sacramento-San Joaquin Delta (California, USA)

    USGS Publications Warehouse

    Jassby, A.D.; Cloern, J.E.

    2000-01-01

    1. The Sacramento San Joaquin River Delta, a complex mosaic of tidal freshwater habitats in California, is the focus of a major ecosystem rehabilitation effort because of significant long-term changes in critical ecosystem functions. One of these functions is the production, transport and transformation of organic matter that constitutes the primary food supply, which may be sub-optimal at trophic levels supporting fish recruitment. A long historical data set is used to define the most important organic matter sources, the factors underlying their variability, and the implications of ecosystem rehabilitation actions for these sources. 2. Tributary-borne loading is the largest organic carbon source on an average annual Delta-wide basis; phytoplankton production and agricultural drainage are secondary; wastewater treatment plant discharge, tidal marsh drainage and possibly aquatic macrophyte production are tertiary; and benthic microalgal production, urban run-off and other sources are negligible. 3. Allochthonous dissolved organic carbon must be converted to particulate form - with losses due to hydraulic flushing and to heterotroph growth inefficiency - before it becomes available to the metazoan food web. When these losses are accounted for, phytoplankton production plays a much larger role than is evident from a simple accounting of bulk organic carbon sources, especially in seasons critical for larval development and recruitment success. Phytoplankton-derived organic matter is also an important component of particulate loading to the Delta. 4. The Delta is a net producer of organic matter in critically dry years but, because of water diversion from the Delta, transport of organic matter from the Delta to important, downstream nursery areas in San Francisco Bay is always less than transport into the Delta from upstream sources. 5. Of proposed rehabilitation measures, increased use of floodplains probably offers the biggest increase in organic matter sources. 6

  12. Organic matter chlorination rates in different boreal soils: the role of soil organic matter content.

    PubMed

    Gustavsson, Malin; Karlsson, Susanne; Oberg, Gunilla; Sandén, Per; Svensson, Teresia; Valinia, Salar; Thiry, Yves; Bastviken, David

    2012-02-07

    Transformation of chloride (Cl(-)) to organic chlorine (Cl(org)) occurs naturally in soil but it is poorly understood how and why transformation rates vary among environments. There are still few measurements of chlorination rates in soils, even though formation of Cl(org) has been known for two decades. In the present study, we compare organic matter (OM) chlorination rates, measured by (36)Cl tracer experiments, in soils from eleven different locations (coniferous forest soils, pasture soils and agricultural soils) and discuss how various environmental factors effect chlorination. Chlorination rates were highest in the forest soils and strong correlations were seen with environmental variables such as soil OM content and Cl(-) concentration. Data presented support the hypothesis that OM levels give the framework for the soil chlorine cycling and that chlorination in more organic soils over time leads to a larger Cl(org) pool and in turn to a high internal supply of Cl(-) upon dechlorination. This provides unexpected indications that pore water Cl(-) levels may be controlled by supply from dechlorination processes and can explain why soil Cl(-) locally can be more closely related to soil OM content and the amount organically bound chlorine than to Cl(-) deposition.

  13. Effects of molecular weight of natural organic matter on cadmium mobility in soil environments and its carbon isotope characteristics.

    PubMed

    Mahara, Y; Kubota, T; Wakayama, R; Nakano-Ohta, T; Nakamura, T

    2007-11-15

    We investigated the role of natural organic matter in cadmium mobility in soil environments. We collected the dissolved organic matter from two different types of natural waters: pond surface water, which is oxic, and deep anoxic groundwater. The collected organic matter was fractionated into four groups with molecular weights (unit: Da (Daltons)) of <1 x 10(3), 1-10 x 10(3), 10-100 x 10(3), and >100 x 10(3). The organic matter source was land plants, based on the carbon isotope ratios (delta(13)C/(12)C). The organic matter in surface water originated from presently growing land plants, based on (14)C dating, but the organic matter in deep groundwater originated from land plants that grew approximately 4000 years ago. However, some carbon was supplied by the high-molecular-weight fraction of humic substances in soil or sediments. Cadmium interacted in a system of siliceous sand, fractionated organic matter, and water. The lowest molecular weight fraction of organic matter (<1 x 10(3)) bound more cadmium than did the higher molecular weight fractions. Organic matter in deep groundwater was more strongly bound to cadmium than was organic matter in surface water. The binding behaviours of organic matter with cadmium depended on concentration, age, molecular weight, and degradation conditions of the organic matter in natural waters. Consequently, the dissolved, low-molecular-weight fraction in organic matter strongly influences cadmium migration and mobility in the environment.

  14. Role of Organic Matter in the Removal of Heavy Metals in Stormwater Runoff

    NASA Astrophysics Data System (ADS)

    Barrett, M.; Ingenloff, C.; Katz, L.

    2011-12-01

    Heavy metals (copper, zinc, and lead) are common constituents in highway runoff and concentrations in runoff from highway facilities are particularly high. These concentrations are also generally higher than observed in natural water bodies and several studies have demonstrated acute and chronic toxicity to aquatic ecosystems. One focus of this project is to assess the potential of sorption to reduce the concentration of metals in runoff. The difficulty evaluating adsorption in multi-component systems is to capture the impacts of background organic matter and other complexing ions on adsorption behavior. Very few studies have evaluated the ability of surface complexation models to predict adsorption in systems that contain organic matter from highway runoff. Moreover, the composition of the organic matter in stormwater runoff can be significantly different from natural organic matter typically used to assess the impact of background organics on metal ion adsorption. This research project specifically addresses these concerns and examines the impact of highway runoff on the adsorption behavior to determine whether existing surface complexation and chemical speciation models and parameter databases can be used to predict adsorption of target metal ions in these waters. Previous research has employed both actual storm water that has been obtained from actual field highway runoff sites as well as synthetic storm water compositions that have attempted to mimic the major components of natural storm water. Researchers and practitioners in the field generally agree on the importance of capturing the background water matrix; however, concerns associated with required volumes, holding times, aging, consistency and temporal and spatial variability often favor the use of synthetic formulations. While synthetic storm water can achieve the required consistency, numerous artifacts can be introduced due to the high reactivity of trace metal ions with background inorganic and

  15. Methylmercury production in estuarine sediments: role of organic matter

    PubMed Central

    Schartup, Amina T.; Mason, Robert P.; Balcom, Prentiss H.; Hollweg, Terill A.; Chen, Celia Y.

    2013-01-01

    Methylmercury (MeHg) affects wildlife and human health mainly through marine fish consumption. In marine systems, MeHg is formed from inorganic mercury (HgII) species primarily in sediments then accumulates and biomagnifies in the food web. Most of the fish consumed in the US are from estuarine and marine systems highlighting the importance of understanding MeHg formation in these productive regions. Sediment organic matter has been shown to limit mercury methylation in estuarine ecosystems, as a result it is often described as the primary control over MeHg production. In this paper, we explore the role of organic matter by looking at the effects of its changing sediment concentrations on the methylation rates across multiple estuaries. We measured sedimentary MeHg production at eleven estuarine sites that were selected for their contrasting biogeochemical characteristics, mercury (Hg) content, and location in the Northeastern US (ME, NH, CT, NY, and NJ). Sedimentary total Hg concentrations ranged across five orders of magnitude, increasing in concentration from the pristine, sandy sediments of Wells (ME), to industrially contaminated areas like Portsmouth (NH) and Hackensack (NJ). We find that methylation rates are the highest at locations with high Hg content (relative to carbon), and that organic matter does not hinder mercury methylation in estuaries. PMID:23194318

  16. Pleistocene to Holocene contrasts in organic matter production and preservation on the California continental margin

    USGS Publications Warehouse

    Dean, W.E.; Gardner, J.V.

    1998-01-01

    Organic matter in sediments from cores collected from the upper continental slope (200-2700 m) off California and southern Oregon shows marked differences in concentration and marine character between the last glacial interval (ca. 24-10 ka) and either Holocene time or last interstadial (oxygen isotope stage 3, ca. 60-24 ka). In general, sediments deposited during Holocene time and stage 3 contain higher amounts of marine organic matter than those deposited during the last glacial interval, and this contrast is greatest in cores collected off southern California. The most profound differences in stage 3 sediments are between predominantly bioturbated sediments and occasional interbeds of laminated sediments. The sediments are from cores collected within the present oxygen minimum zone on the upper continental slope from as far north as the Oregon-California border to as far south as Point Conception. These upper Pleistocene laminated sediments contain more abundant hydrogen-rich (type II) marine algal organic matter than even surface sediments that have large amounts of nonrefractory organic matter. The stable carbon-isotopic composition of the organic matter does not change with time between bioturbated and laminated sediments, indicating that the greater abundance of type II organic matter in the laminated sediments is not due to a change in source but rather represents a greater degree of production and preservation of marine organic matter. The presence of abundant, well-preserved organic matter supports the theory that the oxygen minimum zone in the northeastern Pacific Ocean was more intense, and possibly anoxic, during late Pleistocene time as a result of increased coastal upwelling that enhanced algal productivity.

  17. Organic and Inorganic Matter in Louisiana Coastal Waters: Vermilion, Atchafalaya, Terrebonne, Barataria, and Mississippi Regions.

    EPA Science Inventory

    Chromophoric dissolved organic matter (CDOM) spectral absorption, dissolved organic carbon (DOC) concentration, and the particulate fraction of inorganic (PIM) and organic matter (POM) were measured in Louisiana coastal waters at Vermilion, Atchafalaya, Terrebonne, Barataria, and...

  18. Effects of different forms of plant-derived organic matter on nitrous oxide emissions.

    PubMed

    Qiu, Qingyan; Wu, Lanfang; Ouyang, Zhu; Li, Binbin; Xu, Yanyan

    2016-07-13

    To investigate the impact of different forms of plant-derived organic matter on nitrous oxide (N2O) emissions, an incubation experiment with the same rate of total nitrogen (N) application was carried out at 25 °C for 250 days. Soils were incorporated with maize-derived organic matter (i.e., maize residue-derived dissolved organic matter and maize residues with different C/N ratios) and an inorganic N fertilizer (urea). The pattern and magnitude of nitrous oxide (N2O) emissions were affected by the form of N applied. Single application of maize-derived organic matter resulted in a higher N2O emission than single application of the inorganic N fertilizer or combined application of the inorganic N fertilizer and maize-derived organic matter. The positive effect of maize residue-derived dissolved organic matter (DOM) addition on N2O emissions was relatively short-lived and mainly occurred at the early stage following DOM addition. In contrast, the positive effect induced by maize residue addition was more pronounced and lasted for a longer period. Single application of maize residues resulted in a substantial decrease in soil nitric nitrogen (NO3(-)-N), but it did not affect the production of N2O. No significant relationship between N2O emission and NO3(-)-N and ammonium nitrogen (NH4(+)-N) suggested that the availability of soil N was not limiting the production of N2O in our study. The key factors affecting soil N2O emission were the soil dissolved organic carbon (DOC) content and metabolism quotient (qCO2). Both of them could explain 87% of the variation in cumulative N2O emission. The C/N ratio of maize-derived organic matter was a poor predictor of N2O emission when the soil was not limited by easily available C and the available N content met the microbial N demands for nitrification and denitrification. The results suggested that the magnitude of N2O emission was determined by the impact of organic amendments on soil C availability and microbial activity

  19. Is organic matter alone sufficient to predict isoproturon sorption in calcareous soils?

    PubMed

    El Arfaoui, Achouak; Sayen, Stéphanie; Paris, Michaël; Keziou, Amor; Couderchet, Michel; Guillon, Emmanuel

    2012-08-15

    Eleven soils collected from Champagne-Ardenne area (France) were used to investigate isoproturon sorption in laboratory conditions. Our results identified the organic matter (OM) and the ratio of calcite content to OM content (Rt) as the main two parameters governing isoproturon retention in soils. While organic matter favored pesticide sorption, calcite had an antagonistic effect since it limited isoproturon retention. The Rt ratio of calcite content to organic matter content in soils appeared to be a parameter that should be considered in predictive models in addition to OM in regions presenting calcareous soils. Adsorption of isoproturon as a function of Rt and OM was successfully described through a simple empirical model. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Characterization of dissolved organic matter in an urbanized estuary located in Northeastern Brazil.

    PubMed

    Arguelho, Maria de Lara Palmeira de Macedo; Alves, José do Patrocínio Hora; Monteiro, Adnívia Santos Costa; Garcia, Carlos Alexandre Borges

    2017-06-01

    The Sal River estuary, which is located in the state of Sergipe, Northeastern Brazil, stands out as an urban estuary, anthropogenically impacted by untreated and treated wastewater discharge. Synchronous fluorescence spectroscopy and measurement of dissolved organic carbon (DOC) were used for characterization of dissolved organic matter (DOM) in the estuarine water. Dissolved organic carbon concentrations ranged from 7.5 to 19.0 mg L -1 and, in general, the highest values were recorded during dry season. For both seasons (dry and rainy), DOC presented an inverse linear relationship with salinity, which indicates a conservative dilution of organic matter coming into the estuary. During rainy season, anthropogenic organic constituents and humic substances from land-based sources predominated in DOM composition, carried by river flow. Whereas during the dry season, it has been observed a significant increase of products generated by microbial degradation of anthropogenic organic matter. The relationships between fluorescence intensity and salinity suggest a conservative behavior during rainy season and a non-conservative behavior during dry season, with addition of fluorescent organic matter into the intermediate zone of the estuary. Photodegradation by action of sunlight caused a decrease in fluorescence intensity of humic and tryptophan-like constituents and the release of photoproducts, resulting in an increase in fluorescence intensity of protein-like constituents.

  1. Peer reviewed: Characterizing aquatic dissolved organic matter

    USGS Publications Warehouse

    Leenheer, Jerry A.; Croué, Jean-Philippe

    2003-01-01

    Whether it causes aesthetic concerns such as color, taste, and odor; leads to the binding and transport of organic and inorganic contaminants; produces undesirable disinfection byproducts; provides sources and sinks for carbon; or mediates photochemical processes, the nature and properties of dissolved organic matter (DOM) in water are topics of significant environmental interest. DOM is also a major reactant in and product of biogeochemical processes in which the material serves as a carbon and energy source for biota and controls levels of dissolved oxygen, nitrogen, phosphorus, sulfur, numerous trace metals, and acidity.

  2. Photoproduction of Carbon Monoxide from Natural Organic Matter

    EPA Science Inventory

    Pioneering studies by Valentine provided early kinetic results that used carbon monoxide (CO) production to evaluate the photodecomposition of aquatic natural organic matter (NOM) . (ES&T 1993 27 409-412). Comparatively few kinetic studies have been conducted of the photodegradat...

  3. Organic Matter Quality and its Influence on Carbon Turnover and Stabilization in Northern Peatlands

    NASA Astrophysics Data System (ADS)

    Turetsky, M. R.; Wieder, R. K.

    2002-12-01

    Peatlands cover 3-5 % of the world's ice-free land area, but store about 33 % of global terrestrial soil carbon. Peat accumulation in northern regions generally is controlled by slow decomposition, which may be limited by cold temperatures and water-logging. Poor organic matter quality also may limit decay, and microbial activity in peatlands likely is regulated by the availability of labile carbon and/or nutrients. Conversely, carbon in recalcitrant soil structures may be chemically protected from microbial decay, particularly in peatlands where carbon can be buried in anaerobic soils. Soil organic matter quality is controlled by plant litter chemical composition and the susceptibility of organic compounds to decomposition through time. There are a number of techniques available for characterizing organic quality, ranging from chemical proximate or elemental analysis to more qualitative methods such as nuclear magenetic resonance, pyrolysis/mass spectroscopy, and Fourier transform infrared spectroscopy. We generally have relied on proximate analysis for quantitative determination of several organic fractions (i.e., water-soluble carbohydrates, soluble nonpolars, water-soluble phenolics, holocellulose, and acid insoluble material). Our approaches to studying organic matter quality in relation to C turnover in peatlands include 1) 14C labelling of peatland vegetation along a latitudinal gradient in North America, allowing us to follow the fate of 14C tracer in belowground organic fractions under varying climates, 2) litter bag studies focusing on the role of individual moss species in litter quality and organic matter decomposition, and 3) laboratory incubations of peat to explore relationships between organic matter quality and decay. These studies suggest that proximate organic fractions vary in lability, but that turnover of organic matter is influenced both by plant species and climate. Across boreal peatlands, measures of soil recalcitrance such as acid

  4. Isotopic analysis of cometary organic matter

    NASA Technical Reports Server (NTRS)

    Kerridge, John F.

    1991-01-01

    Carbon isotope ratios have been measured for CN in the coma of Comet Halley and for several CHON particles emitted by Halley. Of these, only the CHON-particle data may be reasonably related to organic matter in the cometary nucleus, but the true range of (C-13)/(C-12) values in those particles is quite uncertain. The D/H ratio in H2O in the Halley coma resembles that in Titan/Uranus.

  5. Improved refractory performance through partnership

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

    Linck, F.E.; Peters, D.

    1995-12-31

    From the early designs and construction of Circulating Fluidized Bed (CFB) boilers, many improvements have been made based upon observations of performance. Included in these improvements have been the refractory linings. The early refractory linings were subjected to extreme fluctuations in temperatures as the units experienced up and down conditions. As the designs were improved refractory failures were mostly due to the operating conditions and other mechanical stresses rather than continual shutdowns and startups. More recent problems observed with refractory linings are localized areas of high erosion, corrosion and cracking which result in hot spots and eventual shutdowns for repair.more » Today the objective of refractory suppliers and installers is to strive towards planned shutdowns rather than emergency shutdowns. This can be accomplished through partnerships between operations, material suppliers and installers. In essence, the concept is a cooperative effort between these groups to solve the variety of refractory problems in order to achieve longer refractory lining performance and less chance for emergency shutdowns. The reliability of the refractory lining is dependent on the successful combination of the material selected, proper design and the installation of the refractory material. Where these three elements combine, the lining has the best chance of performing its intended purpose.« less

  6. Photodissolution of soil organic matter

    USGS Publications Warehouse

    Mayer, L.M.; Thornton, K.R.; Schick, L.L.; Jastrow, J.D.; Harden, J.W.

    2012-01-01

    Sunlight has been shown to enhance loss of organic matter from aquatic sediments and terrestrial plant litter, so we tested for similar reactions in mineral soil horizons. Losses of up to a third of particulate organic carbon occurred after continuous exposure to full-strength sunlight for dozens of hours, with similar amounts appearing as photodissolved organic carbon. Nitrogen dissolved similarly, appearing partly as ammonium. Modified experiments with interruption of irradiation to include extended dark incubation periods increased loss of total organic carbon, implying remineralization by some combination of light and microbes. These photodissolution reactions respond strongly to water content, with reaction extent under air-dry to fully wet conditions increasing by a factor of 3-4 fold. Light limitation was explored using lamp intensity and soil depth experiments. Reaction extent varied linearly with lamp intensity. Depth experiments indicate that attenuation of reaction occurs within the top tens to hundreds of micrometers of soil depth. Our data allow only order-of-magnitude extrapolations to field conditions, but suggest that this type of reaction could induce loss of 10-20% of soil organic carbon in the top 10. cm horizon over a century. It may therefore have contributed to historical losses of soil carbon via agriculture, and should be considered in soil management on similar time scales. ?? 2011 Elsevier B.V.

  7. Quality of fresh organic matter affects priming of soil organic matter and substrate utilization patterns of microbes

    PubMed Central

    Wang, Hui; Boutton, Thomas W.; Xu, Wenhua; Hu, Guoqing; Jiang, Ping; Bai, Edith

    2015-01-01

    Changes in biogeochemical cycles and the climate system due to human activities are expected to change the quantity and quality of plant litter inputs to soils. How changing quality of fresh organic matter (FOM) might influence the priming effect (PE) on soil organic matter (SOM) mineralization is still under debate. Here we determined the PE induced by two 13C-labeled FOMs with contrasting nutritional quality (leaf vs. stalk of Zea mays L.). Soils from two different forest types yielded consistent results: soils amended with leaf tissue switched faster from negative PE to positive PE due to greater microbial growth compared to soils amended with stalks. However, after 16 d of incubation, soils amended with stalks had a higher PE than those amended with leaf. Phospholipid fatty acid (PLFA) results suggested that microbial demand for carbon and other nutrients was one of the major determinants of the PE observed. Therefore, consideration of both microbial demands for nutrients and FOM supply simultaneously is essential to understand the underlying mechanisms of PE. Our study provided evidence that changes in FOM quality could affect microbial utilization of substrate and PE on SOM mineralization, which may exacerbate global warming problems under future climate change. PMID:25960162

  8. Quality of fresh organic matter affects priming of soil organic matter and substrate utilization patterns of microbes.

    PubMed

    Wang, Hui; Boutton, Thomas W; Xu, Wenhua; Hu, Guoqing; Jiang, Ping; Bai, Edith

    2015-05-11

    Changes in biogeochemical cycles and the climate system due to human activities are expected to change the quantity and quality of plant litter inputs to soils. How changing quality of fresh organic matter (FOM) might influence the priming effect (PE) on soil organic matter (SOM) mineralization is still under debate. Here we determined the PE induced by two (13)C-labeled FOMs with contrasting nutritional quality (leaf vs. stalk of Zea mays L.). Soils from two different forest types yielded consistent results: soils amended with leaf tissue switched faster from negative PE to positive PE due to greater microbial growth compared to soils amended with stalks. However, after 16 d of incubation, soils amended with stalks had a higher PE than those amended with leaf. Phospholipid fatty acid (PLFA) results suggested that microbial demand for carbon and other nutrients was one of the major determinants of the PE observed. Therefore, consideration of both microbial demands for nutrients and FOM supply simultaneously is essential to understand the underlying mechanisms of PE. Our study provided evidence that changes in FOM quality could affect microbial utilization of substrate and PE on SOM mineralization, which may exacerbate global warming problems under future climate change.

  9. Quality of fresh organic matter affects priming of soil organic matter and substrate utilization patterns of microbes

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Boutton, Thomas W.; Xu, Wenhua; Hu, Guoqing; Jiang, Ping; Bai, Edith

    2015-05-01

    Changes in biogeochemical cycles and the climate system due to human activities are expected to change the quantity and quality of plant litter inputs to soils. How changing quality of fresh organic matter (FOM) might influence the priming effect (PE) on soil organic matter (SOM) mineralization is still under debate. Here we determined the PE induced by two 13C-labeled FOMs with contrasting nutritional quality (leaf vs. stalk of Zea mays L.). Soils from two different forest types yielded consistent results: soils amended with leaf tissue switched faster from negative PE to positive PE due to greater microbial growth compared to soils amended with stalks. However, after 16 d of incubation, soils amended with stalks had a higher PE than those amended with leaf. Phospholipid fatty acid (PLFA) results suggested that microbial demand for carbon and other nutrients was one of the major determinants of the PE observed. Therefore, consideration of both microbial demands for nutrients and FOM supply simultaneously is essential to understand the underlying mechanisms of PE. Our study provided evidence that changes in FOM quality could affect microbial utilization of substrate and PE on SOM mineralization, which may exacerbate global warming problems under future climate change.

  10. PHOTOCHEMICAL TRANSFORMATIONS OF DISSOLVED ORGANIC MATTER IN A BLACKWATER RIVER

    EPA Science Inventory

    We examined photochemical alterations of dissolved organic matter (DOM) from the Satilla River, a high DOC (10-40 mg/liter) blackwater river of southeast Georgia. Water samples were filtered to remove most organisms, placed in quartz tubes, and incubated under natural sunlight a...

  11. CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) DERIVED FROM DECOMPOSITION OF VARIOUS VASCULAR PLANT AND ALGAL SOURCES

    EPA Science Inventory

    Chromophoric dissolved organic (CDOM) in aquatic environments is derived from the microbial decomposition of terrestrial and microbial organic matter. Here we present results of studies of the spectral properties and photoreactivity of the CDOM derived from several organic matter...

  12. Effect of organic matters on CO2 hydrate phase equilibrium conditions in Na-montmorillonite clay

    NASA Astrophysics Data System (ADS)

    Park, T.; Kyung, D.; Lee, W.

    2013-12-01

    Formation of gas hydrates provides an attractive idea for storing greenhouse gases in a long-term stable geological formation. Since the phase equilibrium conditions of gas hydrates indicate the stability of hydrates, estimation of the phase equilibrium conditions of gas hydrates in marine geological conditions is necessary. In this study, we have identified the effects of organic matters (glycine, glucose, and urea) and solid surface (montmorillonite (MMT)) on the three-phase (liquid-hydrate-vapor) equilibrium conditions of CO2 hydrate. CO2 phase equilibrium experiments were conducted using 0.5mol% organic matter solutions with and without 10g soil mineral were experimentally conducted. Addition of organic matters shifted the phase equilibrium conditions of CO2 hydrate to the higher pressure or lower pressure region because of higher competition of water molecules due to the dissolved organic matters. Presence of MMT also leaded to the higher equilibrium pressure due to the interaction of cations with water molecules. By addition of organic matters to the clay suspension, the hydrate phase equilibrium conditions were less inhibited compared to those of MMT and organic matters independently. The diminished magnitudes by addition of organic matters to the clay suspension (MMT > MMT+urea > MMT+glycine > MMT+glucose > DIW) were different to the order of inhibition degree without MMT (Glucose > glycine > urea > DIW). X-ray diffraction (XRD), scanning electron microscope (SEM), and ion chromatography (IC) analysis were conducted to support the hypothesis that the organic matters interact with cations in MMT interlayer space, and leads to the less inhibition of phase equilibrium conditions. The present study provides basic information for the formation and dissociation of CO2 hydrates in the geological formation when sequestering CO2 as a form of CO2 hydrate.

  13. Input related microbial carbon dynamic of soil organic matter in particle size fractions

    NASA Astrophysics Data System (ADS)

    Gude, A.; Kandeler, E.; Gleixner, G.

    2012-04-01

    This paper investigated the flow of carbon into different groups of soil microorganisms isolated from different particle size fractions. Two agricultural sites of contrasting organic matter input were compared. Both soils had been submitted to vegetation change from C3 (Rye/Wheat) to C4 (Maize) plants, 25 and 45 years ago. Soil carbon was separated into one fast-degrading particulate organic matter fraction (POM) and one slow-degrading organo-mineral fraction (OMF). The structure of the soil microbial community were investigated using phospholipid fatty acids (PLFA), and turnover of single PLFAs was calculated from the changes in their 13C content. Soil enzyme activities involved in the degradation of carbohydrates was determined using fluorogenic MUF (methyl-umbelliferryl phosphate) substrates. We found that fresh organic matter input drives soil organic matter dynamic. Higher annual input of fresh organic matter resulted in a higher amount of fungal biomass in the POM-fraction and shorter mean residence times. Fungal activity therefore seems essential for the decomposition and incorporation of organic matter input into the soil. As a consequence, limited litter input changed especially the fungal community favouring arbuscular mycorrhizal fungi. Altogether, supply and availability of fresh plant carbon changed the distribution of microbial biomass, the microbial community structure and enzyme activities and resulted in different priming of soil organic matter. Most interestingly we found that only at low input the OMF fraction had significantly higher calculated MRT for Gram-positive and Gram-negative bacteria suggesting high recycling of soil carbon or the use of other carbon sources. But on average all microbial groups had nearly similar carbon uptake rates in all fractions and both soils, which contrasted the turnover times of bulk carbon. Hereby the microbial carbon turnover was always faster than the soil organic carbon turnover and higher carbon input

  14. Effect of different kinds of crop residues on aggregate-protected soil organic matter fractions.

    NASA Astrophysics Data System (ADS)

    Huisz, A.

    2009-04-01

    Organic matter content of soils determines many important soil properties, such as soil structure, fertility and water-management. To improve its fertility and quality, returning different kinds of organic matter to soil has a long historical tradition. Ameliorating of soil and enhancing its fertility by enhancing its carbon stock with organic matter incorporation (like farmyard manure, crop residues or green manure) are general practices, but the extent of the amelioration depends much on several factors such as quantity, quality of the used organic matters. Quality of soil organic matters is affected by their chemical build-up, which differs by their origin (i.e. plant species); and their decomposability is affected by particle-size, protection by soil aggregates and the extent of their association to mineral surfaces. In our paper we investigated the effect of three different kinds of organic matter incorporation on aggregate-protected organic matter fractions: (1) Maize stem (M), (2) Wheat straw (W), and (3) Maize stem & Wheat straw (MW). Our samples were originated from Keszthely, Western Hungary, where the texture of the investigated soil is Sandy loam, the type of soil is Eutric Cambisol (soil type FAO), or Alfisol (soil type USDA). SOM fractions might be isolated and measured by physical fractionation of soil (Cambardella and Elliott (1992), Jensen et al. (1992)). Firstly, microaggregates were separated according to their particle-size with physical fractionation (i.e. wet sieving) (Six et al. (2000a)). Each sample was pre-treated by capillary wetting and was sieved for 2 min in an analytic sieve shaker machine with the following aperture sizes: 2 mm, 250 μm, 53 μm. Therefore 4 fractions were resulted: (1) the >2000 μm large macro-, (2) the 250-2000 μm small macro-, (3) the 53-250 μm microaggregates, and (4) the

  15. [Dust and silica exposure on metallurgical furnace maintenance using refractory materials].

    PubMed

    Garattini, S; Barbieri, P G; Bottone, F; Brunelli, E; Carminati, F; Chiari, R; Sarnico, M

    2012-01-01

    In the metallurgical industries the silica risk has long been known, particularly for the refractoryes maintenance workers. The maintenance of furnaces, ladles and tundisches refractory linings, on the current organization of production, is provided by companies under contract. The information available about the characterization of risk for this group of workers are at present inadequate. The study investigates the exposure to dust, also containing free crystalline silica (SLC), through the analysis of samples of commercial products used in the reconstruction of refractory linings of furnaces, ladles and tundisches, materials from the demolition of refractory articles and dust from work areas. It also presents the results of an environmental investigation conducted during the demolition and reconstruction of the refractory in three steel mills. The Authors, by the numerous inspections and the systematic survey of working conditions, have formulated a SLC risk profile and some proposals for prevention.

  16. Jellyfish Lake, Palau: early diagenesis of organic matter in sediments of an anoxic marine lake

    USGS Publications Warehouse

    Orem, W.H.; Burnett, W.C.; Landing, W.M.; Lyons, W.B.; Showers, W.

    1991-01-01

    The major postdepositional change in the sedimentary organic matter is carbohydrate biodegradation. Lignin and aliphatic substances are preserved in the sediments. Dissolved organic matter in pore waters is primarily composed of carbohydrates, reflecting the degradation of sedimentary carbohydrates. Rate constants for organic carbon degradation and sulfate reduction in sediments of the lake are about 10?? lower than in other anoxic sediments. This may reflect the vascular plant source and partly degraded nature of the organic matter reaching the sediments of the lake. -from Authors

  17. Fractionation and characterization of organic matter in wastewater from a swine waste-retention basin

    USGS Publications Warehouse

    Leenheer, Jerry A.; Rostad, Colleen E.

    2004-01-01

    Organic matter in wastewater sampled from a swine waste-retention basin in Iowa was fractionated into 14 fractions on the basis of size (particulate, colloid, and dissolved); volatility; polarity (hydrophobic, transphilic, hydrophilic); acid, base, neutral characteristics; and precipitate or flocculates (floc) formation upon acidification. The compound-class composition of each of these fractions was determined by infrared and 13C-NMR spectral analyses. Volatile acids were the largest fraction with acetic acid being the major component of this fraction. The second most abundant fraction was fine particulate organic matter that consisted of bacterial cells that were subfractionated into extractable lipids consisting of straight chain fatty acids, peptidoglycans components of bacterial cell walls, and protein globulin components of cellular plasma. The large lipid content of the particulate fraction indicates that non-polar contaminants, such as certain pharmaceuticals added to swine feed, likely associate with the particulate fraction through partitioning interactions. Hydrocinnamic acid is a major component of the hydrophobic acid fraction, and its presence is an indication of anaerobic degradation of lignin originally present in swine feed. This is the first study to combine particulate organic matter with dissolved organic matter fractionation into a total organic matter fractionation and characterization.

  18. Experimental Study of Soil Organic Matter Loss From Cultivated Field Plots In The Venezuelan Andes.

    NASA Astrophysics Data System (ADS)

    Bellanger, B.; Huon, S.; Velasquez, F.; Vallès, V.; Girardin A, C.; Mariotti, A. B.

    The question of discriminating sources of organic matter in suspended particles of stream flows can be addressed by using total organic carbon (TOC) concentration and stable isotope (13C, 15N) measurements when constant fluxes of organic matter supply can be assumed. However, little is known on the dynamics of organic matter release during soil erosion and on the temporal stability of its isotopic signature. In this study, we have monitored soil organic carbon loss and water runoff using natural rainfall events on three experimental field plots with different vegetation cover (bare soil, maize and coffee fields), set up on natural slopes of a tropical mountainous watershed in NW Venezuela (09°13'32'' ­ 09°10'00''N, 70°13'49'' ­ 70°18'34''W). Runoff and soil loss are markedly superior for the bare field plot than for the coffee field plot: by a factor 15 ­ 36, respectively, for the five-month experiment, and by a factor 30 ­ 120, respectively, during a single rainfall event experiment. Since runoff and soil organic matter loss are closely linked during most of the flow (at the time scales of this study), TOC concentration in suspended matter is constant. Furthermore, stable isotope compositions reflect those of top-soil organic matter from which they originate.

  19. Overestimation of Crop Root Biomass in Field Experiments Due to Extraneous Organic Matter

    PubMed Central

    Hirte, Juliane; Leifeld, Jens; Abiven, Samuel; Oberholzer, Hans-Rudolf; Hammelehle, Andreas; Mayer, Jochen

    2017-01-01

    Root biomass is one of the most relevant root parameters for studies of plant response to environmental change, soil carbon modeling or estimations of soil carbon sequestration. A major source of error in root biomass quantification of agricultural crops in the field is the presence of extraneous organic matter in soil: dead roots from previous crops, weed roots, incorporated above ground plant residues and organic soil amendments, or remnants of soil fauna. Using the isotopic difference between recent maize root biomass and predominantly C3-derived extraneous organic matter, we determined the proportions of maize root biomass carbon of total carbon in root samples from the Swiss long-term field trial “DOK.” We additionally evaluated the effects of agricultural management (bio-organic and conventional), sampling depth (0–0.25, 0.25–0.5, 0.5–0.75 m) and position (within and between maize rows), and root size class (coarse and fine roots) as defined by sieve mesh size (2 and 0.5 mm) on those proportions, and quantified the success rate of manual exclusion of extraneous organic matter from root samples. Only 60% of the root mass that we retrieved from field soil cores was actual maize root biomass from the current season. While the proportions of maize root biomass carbon were not affected by agricultural management, they increased consistently with soil depth, were higher within than between maize rows, and were higher in coarse (>2 mm) than in fine (≤2 and >0.5) root samples. The success rate of manual exclusion of extraneous organic matter from root samples was related to agricultural management and, at best, about 60%. We assume that the composition of extraneous organic matter is strongly influenced by agricultural management and soil depth and governs the effect size of the investigated factors. Extraneous organic matter may result in severe overestimation of recovered root biomass and has, therefore, large implications for soil carbon modeling and

  20. Overestimation of Crop Root Biomass in Field Experiments Due to Extraneous Organic Matter.

    PubMed

    Hirte, Juliane; Leifeld, Jens; Abiven, Samuel; Oberholzer, Hans-Rudolf; Hammelehle, Andreas; Mayer, Jochen

    2017-01-01

    Root biomass is one of the most relevant root parameters for studies of plant response to environmental change, soil carbon modeling or estimations of soil carbon sequestration. A major source of error in root biomass quantification of agricultural crops in the field is the presence of extraneous organic matter in soil: dead roots from previous crops, weed roots, incorporated above ground plant residues and organic soil amendments, or remnants of soil fauna. Using the isotopic difference between recent maize root biomass and predominantly C3-derived extraneous organic matter, we determined the proportions of maize root biomass carbon of total carbon in root samples from the Swiss long-term field trial "DOK." We additionally evaluated the effects of agricultural management (bio-organic and conventional), sampling depth (0-0.25, 0.25-0.5, 0.5-0.75 m) and position (within and between maize rows), and root size class (coarse and fine roots) as defined by sieve mesh size (2 and 0.5 mm) on those proportions, and quantified the success rate of manual exclusion of extraneous organic matter from root samples. Only 60% of the root mass that we retrieved from field soil cores was actual maize root biomass from the current season. While the proportions of maize root biomass carbon were not affected by agricultural management, they increased consistently with soil depth, were higher within than between maize rows, and were higher in coarse (>2 mm) than in fine (≤2 and >0.5) root samples. The success rate of manual exclusion of extraneous organic matter from root samples was related to agricultural management and, at best, about 60%. We assume that the composition of extraneous organic matter is strongly influenced by agricultural management and soil depth and governs the effect size of the investigated factors. Extraneous organic matter may result in severe overestimation of recovered root biomass and has, therefore, large implications for soil carbon modeling and estimations

  1. Nitrogen Isotopic Composition of Organic Matter in a Pristine Collection IDP

    NASA Technical Reports Server (NTRS)

    Messenger, S.; Nakamura-Messenger, K.; Keller, L. P.; Clemett, S. J.; Nguyen, A. N.; Walker, Robert M.

    2012-01-01

    Anhydrous chondritic porous interplanetary dust particles (CP IDPs) are probable cometary materials that show primitive characteristics, such as unequilibrated mineralogy, fragile structure, and abundant presolar grains and organic matter [1-3]. CP IDPs are richer in aliphatic species and N-bearing aromatic hydrocarbons than meteoritic organics and commonly exhibit highly anomalous H and N isotopic compositions [4,5]. Cometary organic matter is of interest in part because it has escaped the hydrothermal processing experienced by meteorites. However, IDPs are collected using silicon oil that must be removed with strong organic solvents such as hexane. This procedure is likely to have removed some fraction of soluble organic phases in IDPs. We recently reported the first stratospheric collection of IDPs without the use of silicone oil [6]. Here we present initial studies of the carbonaceous material in an IDP from this collection.

  2. The role of aquatic fungi in transformations of organic matter mediated by nutrients

    Treesearch

    Cynthia J. Tant; Amy D. Rosemond; Andrew S. Mehring; Kevin A. Kuehn; John M. Davis

    2015-01-01

    1. We assessed the key role of aquatic fungi in modifying coarse particulate organic matter (CPOM) by affecting its breakdown rate, nutrient concentration and conversion to fine particulate organic matter (FPOM). Overall, we hypothesised that fungal-mediated conditioning and breakdown of CPOM would be accelerated when nutrient concentrations are increased and tested...

  3. Dust inputs and bacteria influence dissolved organic matter in clear alpine lakes.

    PubMed

    Mladenov, N; Sommaruga, R; Morales-Baquero, R; Laurion, I; Camarero, L; Diéguez, M C; Camacho, A; Delgado, A; Torres, O; Chen, Z; Felip, M; Reche, I

    2011-07-26

    Remote lakes are usually unaffected by direct human influence, yet they receive inputs of atmospheric pollutants, dust, and other aerosols, both inorganic and organic. In remote, alpine lakes, these atmospheric inputs may influence the pool of dissolved organic matter, a critical constituent for the biogeochemical functioning of aquatic ecosystems. Here, to assess this influence, we evaluate factors related to aerosol deposition, climate, catchment properties, and microbial constituents in a global dataset of 86 alpine and polar lakes. We show significant latitudinal trends in dissolved organic matter quantity and quality, and uncover new evidence that this geographic pattern is influenced by dust deposition, flux of incident ultraviolet radiation, and bacterial processing. Our results suggest that changes in land use and climate that result in increasing dust flux, ultraviolet radiation, and air temperature may act to shift the optical quality of dissolved organic matter in clear, alpine lakes. © 2011 Macmillan Publishers Limited. All rights reserved.

  4. Ectoenzymatic ratios in relation to particulate organic matter distribution (Ross Sea, Antarctica).

    PubMed

    Misic, C; Povero, P; Fabiano, M

    2002-10-01

    The results of a study on ectoenzymatic activity (the enzyme activity bound to particles larger than 0.2 micro m) and its relation to organic particle concentration are reported here. The sampling was carried out during the 1994 Antarctic spring, at a fixed station (Station 11) in the polynya of the Ross Sea, an area characterized by quick changes in sea ice cover. The sampling was repeated 4 times over a 20-day time period. The particulate organic matter distribution followed the physical structure of the water column, which depends on ice dynamics and is mainly determined by salinity. In the mixed-water surface layer (0-50 m) the concentrations were higher (on average 65.6 micro gC/L) than in the deeper water layer (50 m-bottom) (on average 19.1 micro gC/L). This distribution and quality, expressed by the protein:carbohydrate ratio, linked the particulate organic matter to the phytoplanktonic bloom which was in progress in the area. We determined the kinetic parameters of the glycolytic and proteolytic ectoenzymes and also the total activity for the proteolytic enzyme, in order to evaluate the contribution of the particle-bound activity. We observed higher values in the surface layer than in the deeper layer. b-Glucosidase activity ranged between 0.03 and 0.92 nmol L(-1) h(-1); b-N-acetylglucosaminidase activity was in the range of 0.04-0.58 nmol (L-1) (h-1). The total proteolytic activity (leucine aminopeptidase) ranged between 0.85 and 33.71 nmol L(-1) (h-1). The ectoproteolytic activity was about 35-60% of the total. The Km values were slightly higher for the proteolytic activity (on average 0.43 micro M for ectoproteolytic activity and 0.58 micro M for total proteolytic activity) than for the b-glucosidase (on average 0.36 micro M) and b-N-acetylglucosaminidase (on average 0.17 micro M), showing no remarkable variations in the water column. The ectoenzymatic ratios and their relationship with particulate organic substrates confirm the close link between

  5. Xiphinema americanum as Affected by Soil Organic Matter and Porosity.

    PubMed

    Ponchillia, P E

    1972-07-01

    The effects of four soil types, soil porosity, particle size, and organic matter were tested on survival and migration of Xiphinema americanum. Survival and migration were significantly greater in silt loam than in clay loam and silty clay soils. Nematode numbers were significantly greater in softs planted with soybeans than in fallow softs. Nematode survival was greatest at the higher of two pore space levels in four softs. Migration of X. americanum through soft particle size fractions of 75-150, 150-250, 250-500, 500-700, and 700-1,000 mu was significantly greater in the middle three fractions, with the least occurring in the smallest fraction. Additions of muck to silt loam and loamy sand soils resulted in reductions in survival and migration of the nematode. The fulvic acid fraction of muck, extracted with sodium hydroxide, had a deleterious effect on nematode activity. I conclude that soils with small amounts of air-filled pore space, extremes in pore size, or high organic matter content are deleterious to the migration and survival of X. americanum, and that a naturally occurring toxin affecting this species may be present in native soft organic matter.

  6. ENVIRONMENTAL RESEARCH BRIEF: CHARACTERIZATION OF ORGANIC MATTER IN SOIL AND AQUIFER SOLIDS

    EPA Science Inventory

    The focus of this work was the evaluation of analytical methods to determine and characterize fractions of subsurface organic matter. Major fractions of total organic carbon (TOC) include: particulate organic carbon (POC) in aquifer material, dissolved organic carbon (DOC) and ...

  7. Enzymatic Regulation of Organic Matter Metabolism in Siberia's Kolyma River Watershed

    NASA Astrophysics Data System (ADS)

    Mann, P. J.; Sobczak, W. V.; Vonk, J. E.; Davydova, A.; Schade, J. D.; Bulygina, E. B.; Davydov, S.; Zimov, N.; Holmes, R. M.

    2011-12-01

    Arctic soils contain vast amounts of ancient organic carbon locked up in permafrost. This organic matter can be unlocked via permafrost thaw and bacterial processing. Microbial communities release enzymes into the environment (ectoenzymes) as a means of degrading organic matter and to acquire carbon, nitrogen and phosphorus for assimilation. Limited ectoenzyme production, or unfavourable in-situ conditions (e.g. temperature, oxygen) can limit degradation of permafrost on land. Environmental conditions may become more favourable for bacterial degradation as carbon compounds are released from permafrost into Arctic streams and rivers. We measured the potential activities of a suite of ectoenzymes within surface waters collected from a range of streams and rivers throughout the Kolyma River basin, Siberia. Ectoenzyme activities were additionally measured in Kolyma river waters collected at three distinct periods of the hydrograph (under-ice, freshet and summer conditions). In total, seven enzymes were studied allowing bacterial requirements for a wide range of compounds including lignin, carbohydrates, proteins and cellulose to be assessed. To investigate the lability of the carbon pool within these waters, we measured the biological oxygen demand over 5 days (BOD). Significant correlations were observed between phenol oxidase activity and BOD across all of the study sites, suggesting the rate of phenolic degradation may be a controlling factor in organic carbon metabolism. The activity rate in ectoenzymes that catalyze phosphate, lignin and carbon substrates varied significantly within the Kolyma river over the hydrograph, indicating that seasonal changes in organic matter composition may also shift the limiting resource for bacterial degradation. High activity rates in ectoenzymes that catalyze lignin, chitin, cellulose and proteins were measured in waters draining permafrost ice complexes. These results suggest that organic carbon is continually processed

  8. Black Carbon in Estuarine and Coastal Ocean Dissolved Organic Matter

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Analysis of high-molecular-weight dissolved organic matter (DOM) from two estuaries in the northwest Atlantic Ocean reveals that black carbon (BC) is a significant component of previously uncharacterized DOM, suggesting that river-estuary systems are important exporters of recalcitrant dissolved organic carbon to the ocean.

  9. Isotopic composition of hydrogen in insoluble organic matter from cherts

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, R. V.; Epstein, S.

    1991-01-01

    Robert (1989) reported the presence of unusually enriched hydrogen in the insoluble HF-HCl residue extracted from two chert samples of Eocene and Pliocene ages. Since the presence of heavy hydrogen might be due to the incorporation of extraterrestrial materials, we desired to reexamine the same samples to isolate the D-rich components. Our experiments did not reveal any D-rich components, but the hydrogen isotope composition of the insoluble residue of the two chert samples was well within the range expected for terrestrial organic matter. We also describe a protocol that needs to be followed in the hydrogen isotope analysis of any insoluble organic matter.

  10. The roles of organic matter in the formation of uranium deposits in sedimentary rocks

    USGS Publications Warehouse

    Spirakis, C.S.

    1996-01-01

    Because reduced uranium species have a much smaller solubility than oxidized uranium species and because of the strong association of organic matter (a powerful reductant) with many uranium ores, reduction has long been considered to be the precipitation mechanism for many types of uranium deposits. Organic matter may also be involved in the alterations in and around tabular uranium deposits, including dolomite precipitation, formation of silicified layers, iron-titanium oxide destruction, dissolution of quartz grains, and precipitation of clay minerals. The diagenetic processes that produced these alterations also consumed organic matter. Consequently, those tabular deposits that underwent the more advanced stages of diagenesis, including methanogenesis and organic acid generation, display the greatest range of alterations and contain the smallest amount of organic matter. Because of certain similarities between tabular uranium deposits and Precambrian unconformity-related deposits, some of the same processes might have been involved in the genesis of Precambrian unconformity-related deposits. Hydrologic studies place important constraints on genetic models of various types of uranium deposits. In roll-front deposits, oxidized waters carried uranium to reductants (organic matter and pyrite derived from sulfate reduction by organic matter). After these reductants were oxidized at any point in the host sandstone, uranium minerals were reoxidized and transported further down the flow path to react with additional reductants. In this manner, the uranium ore migrated through the sandstone at a rate slower than the mineralizing ground water. In the case of tabular uranium deposits, the recharge of surface water into the ground water during flooding of lakes carried soluble humic material to the water table or to an interface where humate precipitated in tabular layers. These humate layers then established the chemical conditions for mineralization and related

  11. A mixing-model approach to quantifying sources of organic matter to salt marsh sediments

    NASA Astrophysics Data System (ADS)

    Bowles, K. M.; Meile, C. D.

    2010-12-01

    Salt marshes are highly productive ecosystems, where autochthonous production controls an intricate exchange of carbon and energy among organisms. The major sources of organic carbon to these systems include 1) autochthonous production by vascular plant matter, 2) import of allochthonous plant material, and 3) phytoplankton biomass. Quantifying the relative contribution of organic matter sources to a salt marsh is important for understanding the fate and transformation of organic carbon in these systems, which also impacts the timing and magnitude of carbon export to the coastal ocean. A common approach to quantify organic matter source contributions to mixtures is the use of linear mixing models. To estimate the relative contributions of endmember materials to total organic matter in the sediment, the problem is formulated as a constrained linear least-square problem. However, the type of data that is utilized in such mixing models, the uncertainties in endmember compositions and the temporal dynamics of non-conservative entitites can have varying affects on the results. Making use of a comprehensive data set that encompasses several endmember characteristics - including a yearlong degradation experiment - we study the impact of these factors on estimates of the origin of sedimentary organic carbon in a saltmarsh located in the SE United States. We first evaluate the sensitivity of linear mixing models to the type of data employed by analyzing a series of mixing models that utilize various combinations of parameters (i.e. endmember characteristics such as δ13COC, C/N ratios or lignin content). Next, we assess the importance of using more than the minimum number of parameters required to estimate endmember contributions to the total organic matter pool. Then, we quantify the impact of data uncertainty on the outcome of the analysis using Monte Carlo simulations and accounting for the uncertainty in endmember characteristics. Finally, as biogeochemical processes

  12. Progress of organic matter degradation and maturity of compost produced in a large-scale composting facility.

    PubMed

    Nakasaki, Kiyohiko; Marui, Taketoshi

    2011-06-01

    To monitor the progress of organic matter degradation in a large-scale composting facility, the percentage of organic matter degradation was determined by measuring CO(2) evolution during recomposting of compost samples withdrawn from the facility. The percentage of organic matter degradation was calculated as the ratio of the amount of CO(2) evolved from compost raw material to that evolved from each sample during recomposting in the laboratory composting apparatus. It was assumed that the difference in the cumulative emission of CO(2) between the compost raw material and a sample corresponds to the amount of CO( 2) evolved from the sample in the composting facility. Using this method, the changes in organic matter degradation during composting in practical large-scale composting facilities were estimated and it was found that the percentage of organic matter degradation increased more vigorously in the earlier stages than in the later stages of composting. The percentage of organic matter degradation finally reached 78 and 55% for the compost produced from garbage-animal manure mixture and distillery waste (shochu residue), respectively. It was thus ascertained that organic matter degradation progressed well in both composting facilities. Furthermore, by performing a plant growth assay, it was observed that the compost products of both the facilities did not inhibit seed germination and thus were useful in promoting plant growth.

  13. Evidence for major input of riverine organic matter into the ocean

    USGS Publications Warehouse

    Cao, Xiaoyan; Aiken, George R.; Butler, Kenna D.; Huntington, Thomas G.; Balch, William M.; Mao, Jingdong; Schmidt-Rohr, Klaus

    2018-01-01

    The changes in the structure of XAD-8 isolated dissolved organic matter (DOM) samples along a river (Penobscot River) to estuary (Penobscot Bay) to ocean (across the Gulf of Maine) transect and from the Pacific Ocean were investigated using selective and two dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy coupled with elemental and carbon isotope analysis. The results provide important insights into the nature of relatively stable structures in the river-to-ocean continuum and the enigma of the fate of terrestrial DOM in the marine system. First, lignin and carboxyl-rich alicyclic molecules (CRAMs), which are indistinguishable from mass spectrometry, were clearly differentiated with NMR spectroscopy. NMR unambiguously showed that CRAMs persisted along the river-to-ocean transect and in the Pacific Ocean, while lignin residues dramatically decreased in abundance from the river to the coastal ocean and the Pacific Ocean. The results challenge a previous conclusion that lignin-derived compounds are refractory and can accumulate in the coastal ocean. The loss of terrestrial plant-derived aromatic compounds such as lignin and tannin residues throughout the sequence of riverine, coastal, and open ocean DOM extracts could also partially explain the decreasing organic carbon recovery by XAD-8 isolation and the change in carbon stable isotope composition from riverine DOM (δ13C −27.6‰) to ocean DOM (δ13C −23.0‰) extracts. The observation, from advanced NMR, of similar CRAM molecules in XAD-8 isolated DOM samples from the Penobscot River to the Penobscot Bay and from the ocean refutes a previous conclusion that XAD-isolated DOM samples from seawater and river are distinctly different. The alicyclic structural features of CRAMs and their presence as the major structural units in DOM extracts from the Penobscot River to Gulf of Maine transect, together with the deduced old 14C age of CRAMs in the ocean, imply that terrestrial CRAMs may persist on

  14. Activation energy and energy density: a bioenergetic framework for assessing soil organic matter stability

    NASA Astrophysics Data System (ADS)

    Williams, E. K.; Plante, A. F.

    2017-12-01

    The stability and cycling of natural organic matter depends on the input of energy needed to decompose it and the net energy gained from its decomposition. In soils, this relationship is complicated by microbial enzymatic activity which decreases the activation energies associated with soil organic matter (SOM) decomposition and by chemical and physical protection mechanisms which decreases the concentrations of the available organic matter substrate and also require additional energies to overcome for decomposition. In this study, we utilize differential scanning calorimetry and evolved CO2 gas analysis to characterize differences in the energetics (activation energy and energy density) in soils that have undergone degradation in natural (bare fallow), field (changes in land-use), chemical (acid hydrolysis), and laboratory (high temperature incubation) experimental conditions. We will present this data in a novel conceptual framework relating these energy dynamics to organic matter inputs, decomposition, and molecular complexity.

  15. Terrestrial dissolved organic matter distribution in the North Sea.

    PubMed

    Painter, Stuart C; Lapworth, Dan J; Woodward, E Malcolm S; Kroeger, Silke; Evans, Chris D; Mayor, Daniel J; Sanders, Richard J

    2018-07-15

    The flow of terrestrial carbon to rivers and inland waters is a major term in the global carbon cycle. The organic fraction of this flux may be buried, remineralized or ultimately stored in the deep ocean. The latter can only occur if terrestrial organic carbon can pass through the coastal and estuarine filter, a process of unknown efficiency. Here, data are presented on the spatial distribution of terrestrial fluorescent and chromophoric dissolved organic matter (FDOM and CDOM, respectively) throughout the North Sea, which receives organic matter from multiple distinct sources. We use FDOM and CDOM as proxies for terrestrial dissolved organic matter (tDOM) to test the hypothesis that tDOM is quantitatively transferred through the North Sea to the open North Atlantic Ocean. Excitation emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC) revealed a single terrestrial humic-like class of compounds whose distribution was restricted to the coastal margins and, via an inverse salinity relationship, to major riverine inputs. Two distinct sources of fluorescent humic-like material were observed associated with the combined outflows of the Rhine, Weser and Elbe rivers in the south-eastern North Sea and the Baltic Sea outflow to the eastern central North Sea. The flux of tDOM from the North Sea to the Atlantic Ocean appears insignificant, although tDOM export may occur through Norwegian coastal waters unsampled in our study. Our analysis suggests that the bulk of tDOM exported from the Northwest European and Scandinavian landmasses is buried or remineralized internally, with potential losses to the atmosphere. This interpretation implies that the residence time in estuarine and coastal systems exerts an important control over the fate of tDOM and needs to be considered when evaluating the role of terrestrial carbon losses in the global carbon cycle. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  16. Enhanced dissolution of cinnabar (mercuric sulfide) by dissolved organic matter isolated from the Florida Everglades

    USGS Publications Warehouse

    Ravichandran, Mahalingam; Aiken, George R.; Reddy, Michael M.; Ryan, Joseph N.

    1998-01-01

    Organic matter isolated from the Florida Everglades caused a dramatic increase in mercury release (up to 35 μM total dissolved mercury) from cinnabar (HgS), a solid with limited solubility. Hydrophobic (a mixture of both humic and fulvic) acids dissolved more mercury than hydrophilic acids and other nonacid fractions of dissolved organic matter (DOM). Cinnabar dissolution by isolated organic matter and natural water samples was inhibited by cations such as Ca2+. Dissolution was independent of oxygen content in experimental solutions. Dissolution experiments conducted in DI water (pH = 6.0) had no detectable (<2.5 nM) dissolved mercury. The presence of various inorganic (chloride, sulfate, or sulfide) and organic ligands (salicylic acid, acetic acid, EDTA, or cysteine) did not enhance the dissolution of mercury from the mineral. Aromatic carbon content in the isolates (determined by 13C NMR) correlated positively with enhanced cinnabar dissolution. ζ-potential measurements indicated sorption of negatively charged organic matter to the negatively charged cinnabar (pHpzc = 4.0) at pH 6.0. Possible mechanisms of dissolution include surface complexation of mercury and oxidation of surface sulfur species by the organic matter.

  17. Meteors as a Delivery Vehicle for Organic Matter to the Early Earth

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter; DeVincenzi, D. (Technical Monitor)

    2001-01-01

    Only in recent years has a concerted effort been made to study the circumstances under which extraterrestrial organic matter is accreted on Earth by way of meteors. Meteors are the luminous phenomena associated with the (partial) ablation of meteoric matter and represent the dominant pathway from space to Earth, with the possible exception of rare giant impacts of asteroids and comets. Meteors dominated the supply of organics to the early Earth if organic matter survived this pathway efficiently. Moreover, meteors are a source of kinetic energy that can convert inert atmospheric gases such as CO, N, and H2O into useful compounds, such as HCN and NO. Understanding these processes relies heavily on empirical evidence that is still very limited. Here I report on the observations in hand and discuss their relevance in the context of the origin of life.

  18. The fate or organic matter during planetary accretion - Preliminary studies of the organic chemistry of experimentally shocked Murchison meteorite

    NASA Technical Reports Server (NTRS)

    Tingle, Tracy N.; Tyburczy, James A.; Ahrens, Thomas J.; Becker, Christopher H.

    1992-01-01

    The fate of organic matter in carbonaceous meteorites during hypervelocity (1-2 km/sec) impacts is investigated using results of experiments in which three samples of the Murchison (CM2) carbonaceous chondrite were shocked to 19, 20, and 36 GPa and analyzed by highly sensitive thermal-desorption photoionization mass spectrometry (SALI). The thermal-desorptive SALI mass spectra of unshocked CM2 material revealed presence of indigenous aliphatic, aromatic, sulfur, and organosulfur compounds, and samples shocked to about 20 GPa showed little or no loss of organic matter. On the other hand, samples shocked to 36 GPa exhibited about 70 percent loss of organic material and a lower alkene/alkane ratio than did the starting material. The results suggest that it is unlikely that the indigenous organic matter in carbonaceous chondritelike planetesimals could have survived the impact on the earth in the later stages of earth's accretion.

  19. Lightweight alumina refractory aggregate. Final report

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

    Swansiger, T.G.; Pearson, A.

    1996-07-16

    Objective was to develop a lightweight, high alumina refractory aggregate for use in various high performance insulating (low thermal conductivity) refractory applications (e.g., in the aluminium, glass, cement, and iron and steel industries). A new aggregate process was developed through bench and pilot-scale experiments involving extrusion of a blend of calcined and activated alumina powders and organic extrusion aids and binders. The aggregate, with a bulk density approaching 2.5 g/cc, exhibited reduced thermal conductivity and adequate fired strength compared to dense tabular aggregate. Refractory manufacturers were moderately enthusiastic over the results. Alcoa prepared an economic analysis for producing lightweight aggregate,more » based on a retrofit of this process into existing Alcoa production facilities. However, a new, competing lightweight aggregate material was developed by another company; this material (Plasmal{trademark})had a significantly more favorable cost base than the Alcoa/DOE material, due to cheap raw materials and fewer processing steps. In late 1995, Alcoa became a distributor of Plasmal. Alcoa estimated that {ge}75% of the market originally envisioned for the Alcoa/DOE aggregate would be taken by Plasmal. Hence, it was decided to terminate the contract without the full- scale demonstration.« less

  20. The Preservation of Organic Matter and its Signatures at Experimental Lava Flow Interfaces: Implications for Mars

    NASA Astrophysics Data System (ADS)

    Junium, C. K.; Karson, J. A.; Kahan, T.

    2015-12-01

    The oxidizing nature of Martian soils suggests that the preservation of organic molecules or any direct evidence for life at the surface may not be possible. Future rover missions will need to focus on a variety localitions including those that provide the best possibility for the preservation of organic matter. Volcanic glass and basalt flow surfaces are favored environments for microbial colonization on Earth and this may have been similar on an early Mars. Trace metals and nutrients from easily weathered surface would have provided nutrients as well as substrates for chemolithoautotrophs. In regions of igneous activity, successive flows could overrun microbial communities, trapping potential organic signatures between flows. Here we present experimental evidence for the preservation of organic matter between lava flows and that flow interfaces may be excellent sites for exploratory efforts in the search for Martian biosignatures. We performed a series of experiments using the infrastructure of the Syracuse Lava Project that allows for natural-scale lava flows of up to several hundred kilograms. We subjected cyanobacterial organic matter to overrun by lava under a variety of conditions. In all cases organic matter was preserved between lava flows as chars on the overrun 'colonized" lava and as thin shiny carbon coatings on the overriding flow. The carbon coatings are likely the result of rapid heating and pyrolysis of organic matter that sears to the underside of the overriding lava. Controls yielded no positive signatures for organic matter. We also tested the degree to which the organic matter could be detected remotely using technologies that are found on the Mars Science Laboratory or planned for future missions. We employed elemental and stable isotopes analysis, and Raman spectroscopy. Elemental analysis demonstrated that organic carbon and nitrogen remain in the charred material and that the carbon and nitrogen isotopes of the chars do not deviate

  1. Particulate Organic Matter Distribution along the Lower Amazon River: Addressing Aquatic Ecology Concepts Using Fatty Acids

    PubMed Central

    Mortillaro, Jean-Michel; Rigal, François; Rybarczyk, Hervé; Bernardes, Marcelo; Abril, Gwenaël; Meziane, Tarik

    2012-01-01

    One of the greatest challenges in understanding the Amazon basin functioning is to ascertain the role played by floodplains in the organic matter (OM) cycle, crucial for a large spectrum of ecological mechanisms. Fatty acids (FAs) were combined with environmental descriptors and analyzed through multivariate and spatial tools (asymmetric eigenvector maps, AEM and principal coordinates of neighbor matrices, PCNM). This challenge allowed investigating the distribution of suspended particulate organic matter (SPOM), in order to trace its seasonal origin and quality, along a 800 km section of the Amazon river-floodplain system. Statistical analysis confirmed that large amounts of saturated FAs (15:0, 18:0, 24:0, 25:0 and 26:0), an indication of refractory OM, were concomitantly recorded with high pCO2 in rivers, during the high water season (HW). Contrastingly, FAs marker which may be attributed in this ecosystem to aquatic plants (18:2ω6 and 18:3ω3) and cyanobacteria (16:1ω7), were correlated with higher O2, chlorophyll a and pheopigments in floodplains, due to a high primary production during low waters (LW). Decreasing concentrations of unsaturated FAs, that characterize labile OM, were recorded during HW, from upstream to downstream. Furthermore, using PCNM and AEM spatial methods, FAs compositions of SPOM displayed an upstream-downstream gradient during HW, which was attributed to OM retention and the extent of flooded forest in floodplains. Discrimination of OM quality between the Amazon River and floodplains corroborate higher autotrophic production in the latter and transfer of OM to rivers at LW season. Together, these gradients demonstrate the validity of FAs as predictors of spatial and temporal changes in OM quality. These spatial and temporal trends are explained by 1) downstream change in landscape morphology as predicted by the River Continuum Concept; 2) enhanced primary production during LW when the water level decreased and its residence time

  2. Characterization of water-soluble organic matter isolated from atmospheric fine aerosol

    NASA Astrophysics Data System (ADS)

    Kiss, Gyula; Varga, BáLint; Galambos, IstváN.; Ganszky, Ildikó

    2002-11-01

    Atmospheric fine aerosol (dp < 1.5 μm) was collected at a rural site in Hungary from January to September 2000. The total carbon concentration ranged from 5 to 13 μg m-3 and from 3 to 6 μg m-3 in the first three months and the rest of the sampling period, respectively. On average, water-soluble organic carbon (WSOC) accounted for 66% of the total carbon concentration independent of the season. A variable fraction of the water-soluble organic constituents (38-72% of WSOC depending on the sample) was separated from inorganic ions and isolated in pure organic form by using solid phase extraction on a copolymer sorbent. This fraction was experimentally characterized by an organic matter to organic carbon mass ratio of 1.9, and this value did not change with the seasons. Furthermore, the average elemental composition (molar ratio) of C:H:N:O ≈ 24:34:1:14 of the isolated fraction indicated the predominance of oxygenated functional groups, and the low hydrogen to carbon ratio implied the presence of unsaturated or polyconjugated structures. These conclusions were confirmed by UV, fluorescence, and Fourier transform infrared (FTIR) studies. On the basis of theoretical considerations, the organic matter to organic carbon mass ratio was estimated to be 2.3 for the nonisolated water-soluble organic fraction, resulting in an overall ratio of 2.1 for the WSOC. In order to extend the scope of this estimation to the total organic carbon, which is usually required in mass closure calculations, the aqueous extraction was followed by sequential extraction with acetone and 0.01 M NaOH solution. As a result, a total organic matter to total organic carbon mass ratio of 1.9-2.0 was estimated, but largely on the basis of experimental data.

  3. [Effects of Tillage on Distribution of Heavy Metals and Organic Matter Within Purple Paddy Soil Aggregates].

    PubMed

    Shi, Qiong-bin; Zhao, Xiu-lan; Chang, Tong-ju; Lu, Ji-wen

    2016-05-15

    A long-term experiment was utilized to study the effects of tillage methods on the contents and distribution characteristics of organic matter and heavy metals (Cu, Zn, Pb, Cd, Fe and Mn) in aggregates with different sizes (including 1-2, 0.25-1, 0.05-0.25 mm and < 0.05 mm) in a purple paddy soil under two tillage methods including flooded paddy field (FPF) and paddy-upland rotation (PR). The relationship between heavy metals and organic matter in soil aggregates was also analyzed. The results showed that the aggregates of two tillage methods were dominated by 0.05-0.25 mm and < 0.05 mm particle size, respectively. The contents of organic matter in each aggregate decreased with the decrease of aggregate sizes, however, compared to PR, FPF could significantly increase the contents of organic matter in soils and aggregates. The tillage methods did not significantly affect the contents of heavy metals in soils, but FPF could enhance the accumulation and distribution of aggregate, organic matter and heavy metals in aggregates with diameters of 1-2 mm and 0.25-1 mm. Correlation analysis found that there was a negative correlation between the contents of heavy metals and organic matter in soil aggregates, but a positive correlation between the amounts of heavy metal and organic matter accumulated in soil aggregates. From the slope of the correlation analysis equations, we could found that the sensitivities of heavy metals to the changes of soil organic matters followed the order of Mn > Zn > Pb > Cu > Fe > Cd under the same tillage. When it came to the same heavy metal, it was more sensitive in PR than in FPF.

  4. Soil organic matter fractions in experimental forested watersheds

    Treesearch

    Jennifer L. Parker; Ivan J. Fernandez; Lindsey E. Rustad; Stephen A. Norton

    2002-01-01

    Recent concerns about climate change and atmospheric greenhouse gas concentrations have demonstrated the importance of understanding ecosystem C source/sink relationships. Soil organic matter fractionation was carried out in three paired, forested watershed sites where one of each watershed pair represented a different ecosystem perturbation. The perturbations were 8...

  5. The Organic Matter Molecular Characteristics of Pyrogenic Solids and Their Aqueous Leachable Fractions

    NASA Astrophysics Data System (ADS)

    Wozniak, A. S.; Hatcher, P.; Mitra, S.; Bostick, K. W.; Zimmerman, A. R.

    2016-02-01

    Pyrogenic organic matter (Py-OM), or black carbon (BC), derives from the incomplete combustion of fossil fuels and biomass and is recognized for its impacts on soil chemistry, pollutant transport, climate, and regional and global carbon cycling. In fact, Py-OM is commonly applied to agricultural plots, in the form of "biochars," with the intention of enhancing agricultural production and the expectation of a carbon sequestration side benefit due to Py-OM's refractory and immobile nature. However, several studies of riverine, estuarine, and oceanic waters have detected tracers of dissolved Py-OM in appreciable quantities suggesting that it is more mobile in the environment than previously expected. The quantities and impacts of Py-OM released to aqueous systems are likely dependent on Py-OM molecular characteristics which in turn likely depend on initial combustion conditions and environmental processing. Yet, very little is known about the detailed molecular composition of these materials, let alone their relationships with combustion and environmental processing. Here, pyrophosphate extractable and water leachable components of a range of Py-OM materials (natural charcoals aged in the environment for variable lengths of time, oak and grass combusted over a range of temperatures) are examined by Fourier transform ion cyclotron resonance mass spectrometry. The molecular characteristics of the dissolved and pyrophosphate extractable Py-OM is then compared in the context of production conditions. Results of this study will greatly improve our understanding of Py-OM cycling between watersheds and the oceans.

  6. Organic matter and containment of uranium and fissiogenic isotopes at the Oklo natural reactors

    USGS Publications Warehouse

    Nagy, B.; Gauthier-Lafaye, F.; Holliger, P.; Davis, D.W.; Mossman, D.J.; Leventhal, J.S.; Rigali, M.J.; Parnell, J.

    1991-01-01

    SOME of the Precambrian natural fission reactors at Oklo in Gabon contain abundant organic matter1,2, part of which was liquefied at the time of criticality and subsequently converted to a graphitic solid3,4. The liquid organic matter helps to reduce U(VI) to U(IV) from aqueous solutions, resulting in the precipitation of uraninite5. It is known that in the prevailing reactor environments, precipitated uraninite grains incorporated fission products. We report here observations which show that these uraninite crystals were held immobile within the resolidified, graphitic bitumen. Unlike water-soluble (humic) organic matter, the graphitic bituminous organics at Oklo thus enhanced radionu-clide containment. Uraninite encased in solid graphitic matter in the organic-rich reactor zones lost virtually no fissiogenic lan-thanide isotopes. The first major episode of uranium and lead migration was caused by the intrusion of a swarm of adjacent dolerite dykes about 1,100 Myr after the reactors went critical. Our results from Oklo imply that the use of organic, hydrophobic solids such as graphitic bitumen as a means of immobilizing radionuclides in pretreated nuclear waste warrants further investigation. ?? 1991 Nature Publishing Group.

  7. Tracing sources of organic matter in adjacent urban streams having different degrees of channel modification.

    PubMed

    Duan, Shuiwang; Amon, Rainer M W; Brinkmeyer, Robin L

    2014-07-01

    Urbanization and stream-channel modifications affect organic matter concentrations and quality in streams, by altering allochthonous organic matter input and in-stream transformation. This study uses multiple tracers (δ(13)C, δ(15)N, C/N ratio, and chlorophyll-a) to track sources of organic matter in two highly urbanized bayous in Houston (Texas, USA). Wastewater treatment plants (WWTPs) are located in headwaters of both bayous and contribute more than 75% to water flow. Low isotopic relatedness to natural end-members and enriched δ(15)N values suggest the influence of WWTPs on the composition of all organic matter fractions. The two bayous differ in degree of channel improvement resulting in different responses to hydrological conditions. During high flow conditions, the influence of terrestrial organic matter and sediment resuspension was much more pronounced in the Buffalo Bayou than in the concrete-lined White Oak Bayou. Particulate organic matter (POM) in White Oak Bayou had similar values of enriched δ(15)N in all subsegments, whereas in Buffalo Bayou, the degree of δ(15)N enrichment was less in the subsegments of the lower watershed. The difference in riparian zone contributions and interactions with sediments/soils was likely responsible for the compositional differences between the two bayous. Phytoplankton inputs were significantly higher in the bayous, especially in slow-flowing sections, relative to the reference sites, and elevated phytoplankton inputs accounted for the observed stable C isotope differences between FPOM and high molecular weight dissolved organic matter (HMW DOM). Relative to POM, HMW DOM in the bayous was similar to WWTP effluents and showed minor longitudinal variability in both streams suggesting that WWTPs contribute much of the DOM in the systems. Urbanization has a major influence on organic matter sources and quality in these urban water bodies and these changes seem further enhanced by stream channel modifications

  8. Relative humidity-dependent viscosity of secondary organic material from toluene photo-oxidation and possible implications for organic particulate matter over megacities

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

    Song, Mijung; Liu, Pengfei F.; Hanna, Sarah J.

    To improve predictions of air quality, visibility, and climate change, knowledge of the viscosities and diffusion rates within organic particulate matter consisting of secondary organic material (SOM) is required. Most qualitative and quantitative measurements of viscosity and diffusion rates within organic particulate matter have focused on SOM particles generated from biogenic volatile organic compounds (VOCs) such as α-pinene and isoprene. In this study, we quantify the relative humidity (RH)-dependent viscosities at 295±1K of SOM produced by photo-oxidation of toluene, an anthropogenic VOC. The viscosities of toluene-derived SOM were 2 × 10 ₋1 to ~6 ×10 6Pa s from 30 tomore » 90%RH, and greater than ~2 × 10 8 Pa s (similar to or greater than the viscosity of tar pitch) for RH ≤ 17%. These viscosities correspond to Stokes–Einstein-equivalent diffusion coefficients for large organic molecules of ~2 ×10 ₋15cm 2s ₋1 for 30 % RH, and lower than ~3 × 10 ₋17cm 2s ₋1 for RH ≤ 17 %. Based on these estimated diffusion coefficients, the mixing time of large organic molecules within 200 nm toluene-derived SOM particles is 0.1–5 h for 30% RH, and higher than ~100 h for RH ≤ 17%. As a starting point for understanding the mixing times of large organic molecules in organic particulate matter over cities, we applied the mixing times determined for toluene-derived SOM particles to the world's top 15 most populous megacities. If the organic particulate matter in these megacities is similar to the toluene-derived SOM in this study, in Istanbul, Tokyo, Shanghai, and São Paulo, mixing times in organic particulate matter during certain periods of the year may be very short, and the particles may be well-mixed. On the other hand, the mixing times of large organic molecules in organic particulate matter in Beijing, Mexico City, Cairo, and Karachi may be long and the particles may not be well-mixed in the afternoon (15:00–17:00 LT) during certain times of

  9. Laboratory Investigations of the Complex Refractory Organic Material Produced from Irradiation of Pluto Ice Analogs

    NASA Technical Reports Server (NTRS)

    Materese, Christopher K.; Cruikshank, Dale P.; Sanford, Scott A.; Imanaka, Hiroshi

    2014-01-01

    Much of Pluto's surface consists of N2 ice with smaller amounts of CH4 and CO ices. Despite the low temperature (approximately 45K), chemistry can be driven in the surface ices by radiation processing such as cosmic ray bombardment. When cosmic rays strike the surface, much of their energy is dispersed in the form of secondary electrons, which in turn drive much of the resulting chemical reactions. Laboratory experiments designed to simulate the conditions on these icy bodies may provide insight into this chemistry. Significant progress has been made in the laboratory toward understanding the smaller, simple compounds produced in the solid phase by radiation processing of (N2, CH4, CO) ices (Bohn et al. 1994; Moore & Hudson 2003; Hodyss et al. 2011; Kim and Kaiser 2012). Recently Materese et al. (2014) used a variety of techniques to better characterize the refractory materials produced from the UV photo-irradiation of N2:CH4:CO ices. However, because Pluto's atmosphere is optically thick to Lyman-alpha UV radiation it is important to re-examine the results using an alternate radiation source. Our latest work has consisted of the analysis of refractory materials produced from the electron bombardment of low temperature N2(-), CH4(-), and CO(-)containing ices (100:1:1). The ice mixture was chosen to be analogous to the known surface ices on Pluto and the radiation source was chosen to mimic the secondary electrons produced by cosmic rays bombardment. The residues were studied using multiple chemical techniques including, infrared (IR) spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, and gas chromatography coupled with mass spectrometry (GC-MS). The organic residues produced in these experiments can be seen as an analog for the refractory component of the surface of Pluto, and are compared with the residues previously obtained from UV photo-irradiation. UV and near- IR spectroscopy of the surfaces of Pluto and Charon during the encounter with

  10. Peatland Organic Matter Chemistry Trends Over a Global Latitudinal Gradient

    NASA Astrophysics Data System (ADS)

    Verbeke, B. A.; Hodgkins, S. B.; Carson, M. A.; Lamit, L. J.; Lilleskov, E.; Chanton, J.

    2017-12-01

    Peatlands contain a significant amount of the global soil carbon, and the climate feedback of carbon cycling within these peatland systems is still relatively unknown. Organic matter composition of peatlands plays a major role in determining carbon storage, and while high latitude peatlands seem to be the most sensitive to climate change, a global picture of peat organic matter chemistry is required to improve predictions and models of greenhouse gas emissions fueled by peatland decomposition. The objective of this research is to test the hypothesis that carbohydrate content of peatlands near the equator will be lower than high latitude peatlands, while aromatic content will be higher. As a part of the Global Peatland Microbiome Project (GPMP), around 2000 samples of peat from 10 to 70 cm across a latitudinal gradient of 79 N to 53 S were measured with Fourier transform infrared spectroscopy (FTIR) to examine the organic matter functional groups of peat. Carbohydrate and aromatic content, as determined by FTIR, are useful proxies of decomposition potential and recalcitrance, respectively. We found a highly significant relationship between carbohydrate and aromatic content, latitude, and depth. Carbohydrate content of high latitude sites were significantly greater than at sites near the equator, in contrast to aromatic content which showed the opposite trend. It is also clear that carbohydrate content decreases with depth while aromatic content increases with depth. Higher carbohydrate content at higher latitudes indicates a greater potential for lability and resultant mineralization to form the greenhouse gases, carbon dioxide and methane, whereas the composition of low latitude peatlands is consistent with their apparent stability. We speculate that the combination of low carbohydrates and high aromatics at warmer locations near the equator could foreshadow the organic matter composition of high latitude peat transitioning to a more recalcitrant form with a

  11. Organic Matter Detection on Mars by Pyrolysis-FTIR: An Analysis of Sensitivity and Mineral Matrix Effects

    NASA Astrophysics Data System (ADS)

    Gordon, Peter R.; Sephton, Mark A.

    2016-11-01

    Returning samples from Mars will require an effective method to assess and select the highest-priority geological materials. The ideal instrument for sample triage would be simple in operation, limited in its demand for resources, and rich in produced diagnostic information. Pyrolysis-Fourier infrared spectroscopy (pyrolysis-FTIR) is a potentially attractive triage instrument that considers both the past habitability of the sample depositional environment and the presence of organic matter that may reflect actual habitation. An important consideration for triage protocols is the sensitivity of the instrumental method. Experimental data indicate pyrolysis-FTIR sensitivities for organic matter at the tens of parts per million level. The mineral matrix in which the organic matter is hosted also has an influence on organic detection. To provide an insight into matrix effects, we mixed well-characterized organic matter with a variety of dry minerals, to represent the various inorganic matrices of Mars samples, prior to analysis. During pyrolysis-FTIR, serpentinites analogous to those on Mars indicative of the Phyllocian Era led to no negative effects on organic matter detection; sulfates analogous to those of the Theiikian Era led, in some instances, to the combustion of organic matter; and palagonites, which may represent samples from the Siderikian Era, led, in some instances, to the chlorination of organic matter. Any negative consequences brought about by these mineral effects can be mitigated by the correct choice of thermal extraction temperature. Our results offer an improved understanding of how pyrolysis-FTIR can perform during sample triage on Mars.

  12. Characterizing Groundwater Sources of Organic Matter to Arctic Coastal Waters

    NASA Astrophysics Data System (ADS)

    Connolly, C. T.; Spencer, R. G.; Cardenas, M. B.; Bennett, P. C.; McNichol, A. P.; McClelland, J. W.

    2016-12-01

    The Arctic is projected to transition from a runoff-dominated system to a groundwater-dominated system as permafrost thaws due to climate change. This fundamental shift in hydrology is expected to increase groundwater flow to Arctic coastal waters, which may be a significant source of dissolved organic matter (DOM) to these waters—even under present conditions—that has been largely overlooked. Here we quantify and elucidate sources of groundwater DOM inputs to lagoons along the eastern Alaskan Beaufort Sea coast using an approach that combines concentration measurements and radiocarbon dating of groundwater, soil profiles, and soil leachable dissolved organic carbon (DOC). Samples were collected in late summer, when soil thaw depths (active layer) were near their maximum extent. As anticipated, the radiocarbon age of bulk soil organic matter increased with depth (modern - 6,100 yBP), while the amount of extractable DOC decreased with depth within the active layer. However, amounts of extractable DOC increased dramatically in thawed permafrost samples collected directly below the actively layer. Concentrations of DOM in groundwater (ranging from 902 to 5,118 μmolL-1 DOC) are one to two orders of magnitude higher than those measured in lagoons and nearby river water. In contrast, the 14C-DOC ages of groundwater (1,400 ± 718 s.d. yBP), lagoon water (1,750 yBP), and river water (1,610 yBP) are comparable. Together these results suggest that: (1) groundwater provides a highly concentrated input of old DOC to Arctic coastal waters; (2) groundwater DOM is likely sourced from organic matter spanning the entire soil profile; and (3) the DOM in rivers along the eastern Alaskan Beaufort Sea coast during late summer is strongly influenced by groundwater sources, but is much lower in concentration due to photo-mineralization and/or biological consumption. These results are key for assessing how changes in land-ocean export of organic matter as permafrost thaws will change

  13. Cytotoxicity and genotoxicity induced in vitro by solvent-extractable organic matter of size-segregated urban particulate matter.

    PubMed

    Velali, Ekaterini; Papachristou, Eleni; Pantazaki, Anastasia; Choli-Papadopoulou, Theodora; Argyrou, Nikoleta; Tsourouktsoglou, Theodora; Lialiaris, Stergios; Constantinidis, Alexandros; Lykidis, Dimitrios; Lialiaris, Thedore S; Besis, Athanasios; Voutsa, Dimitra; Samara, Constantini

    2016-11-01

    Three organic fractions of different polarity, including a non polar organic fraction (NPOF), a moderately polar organic fraction (MPOF), and a polar organic fraction (POF) were obtained from size-segregated (<0.49, 0.49-0.97, 0.97-3 and >3 μm) urban particulate matter (PM) samples, and tested for cytotoxicity and genotoxicity using a battery of in vitro assays. The cytotoxicity induced by the organic PM fractions was measured by the mitochondrial dehydrogenase (MTT) cell viability assay applied on MRC-5 human lung epithelial cells. DNA damages were evaluated through the comet assay, determination of the poly(ADP-Ribose) polymerase (PARP) activity, and the oxidative DNA adduct 8-hydroxy-deoxyguanosine (8-OHdG) formation, while pro-inflammatory effects were assessed by determination of the tumor necrosis factor-alpha (TNF-α) mediator release. In addition, the Sister Chromatid Exchange (SCE) inducibility of the solvent-extractable organic matter was measured on human peripheral lymphocyte. Variations of responses were assessed in relation to the polarity (hence the expected composition) of the organic PM fractions, particle size, locality, and season. Organic PM fractions were found to induce rather comparable Cytotoxicity and genotoxicity of PM appeared to be rather independent from the polarity of the extractable organic PM matter (EOM) with POF often being relatively more toxic than NPOF or MPOF. All assays indicated stronger mass-normalized bioactivity for fine than coarse particles peaking in the 0.97-3 and/or the 0.49-0.97 μm size ranges. Nevertheless, the air volume-normalized bioactivity in all assays was highest for the <0.49 μm size range highlighting the important human health risk posed by the inhalation of these quasi-ultrafine particles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Aquatic Organic Matter Fluorescence - from phenomenon to application

    NASA Astrophysics Data System (ADS)

    Reynolds, Darren

    2014-05-01

    The use of fluorescence to quantify and characterise aquatic organic matter in river, ocean, ground water and drinking and waste waters has come along way since its discovery as a phenomenon in the early 20th century. For example, there are over 100 papers published each year in international peer reviewed journals, an order of magnitude increase since a decade ago (see Figure taken from ISI database from 1989 to 2007 for publications in the fields of river water and waste water). Since then it has been extensively used as a research tool since the 1990's by scientists and is currently used for a wide variety of applications within a number of sectors. Universities, organisations and companies that research into aquatic organic matter have either recently readily use appropriate fluorescence based techniques and instrumentation. In industry and government, the technology is being taken up by environmental regulators and water and wastewater companies. This keynote presentation will give an overview of aquatic organic matter fluorescence from its conception as a phenomenon through to its current use in a variety of emerging applications within the sectors concerned with understanding, managing and monitoring the aquatic environment. About the Speaker Darren Reynolds pioneered the use of fluorescence spectroscopy for the analysis of wastewaters in the 1990's. He currently leads a research group within the Centre for Research in Biosciences and sits on the Scientific Advisory Board for the Institute of Bio-Sensing Technology at the University of the West of England, Bristol. He is a multidisciplinary scientist concerned with the development of technology platforms for applications in the fields of environment/agri-food and health. His current research interests include the development of optical technologies and techniques for environmental and biological sensing and bio-prospecting applications. He is currently involved in the development and use of synthetic biology

  15. Observed effects of soil organic matter content on the microwave emissivity of soils

    NASA Technical Reports Server (NTRS)

    O'Neill, P. E.; Jackson, T. J.

    1990-01-01

    In order to determine the significance of organic matter content on the microwave emissivity of soils when estimating soil moisture, field experiments were conducted in which 1.4 GHz microwave emissivity data were collected over test plots of sandy loam soil with different organic matter levels (1.8, 4.0, and 6.1 percent) for a range of soil moisture values. Analyses of the observed data show only minor variation in microwave emissivity due to a change in organic matter content at a given moisture level for soils with similar texture and structure. Predictions of microwave emissivity made using a dielectric model for aggregated soils exhibit the same trends and type of response as the measured data when appropriate values for the input parameters were utilized.

  16. Observed effects of soil organic matter content on the microwave intensity of soils

    NASA Technical Reports Server (NTRS)

    Jackson, T. J.; Oneill, P. E.

    1988-01-01

    In order to determine the significance of organic matter content on the microwave emissivity of soils when estimating soil moisture, field experiments were conducted in which 1.4 GHz microwave emissivity data were collected over test plots of sandy loam soil with different organic matter levels (1.8, 4.0, and 6.1 percent) for a range of soil moisture values. Analyses of the observed data show only minor variation in microwave emissivity due to a change in organic matter content at a given moisture level for soils with similar texture and structure. Predictions of microwave emissivity made using a dielectric model for aggregated soils exhibit the same trends and type of response as the measured data when appropriate values for the input parameters were utilized.

  17. Assessment of the unidentified organic matter fraction in fogwater using fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Valsaraj, K.; Birdwell, J.

    2010-07-01

    Dissolved organic matter (DOM) in fogwaters from southeastern Louisiana and central-eastern China has been characterized using excitation-emission matrix (EEM) fluorescence spectroscopy. The results demonstrate that fluorescence spectroscopy can be used to obtain a qualitative assessment of the large fraction of fogwater organic carbon (~40 - 80% by weight) that cannot be identified in terms of specific chemical compounds. The method has the principle advantage that it can be applied at natural abundance concentrations, thus eliminating the need for large sample volumes required to isolate DOM for characterization by other spectroscopic (NMR, FTIR) and chemical (elemental) analyses. It was anticipated that the fogwater organic matter fluorescence spectra would resemble those of surface and rain waters, containing peaks indicative of both humic substances and fluorescent amino acids. Humic- and protein-like fluorophores were observed in the fogwater spectra and fluorescence-derived indices had values comparable to other natural waters. Biological character (intensity of tyrosine and tryptophan peaks) was found to increase with organic carbon concentration. Fogwater organic matter appears to contain a mixture of terrestrially- and microbially-derived material. The fluorescence results show that most of the unidentified fogwater organic carbon can be represented by humic-like and biologically-derived substances similar to those present in other aquatic systems.

  18. Comprehensive assessment of precursors, diagenesis, and reactivity to water treatment of dissolved and colloidal organic matter

    USGS Publications Warehouse

    Leenheer, J.A.

    2004-01-01

    A comprehensive isolation, fractionation, and characterization research approach was developed for dissolved and colloidal organic matter (DOM) in water, and it was applied to various surface- and groundwaters to assess DOM precursors, DOM diagenesis, and DOM reactivity to water treatment processes. Major precursors for natural DOM are amino sugars, condensed tannins, and terpenoids. Amino sugar colloids derived from bacterial cell walls are incompletely removed by drinking water treatment and foul reverse osmosis membranes, but are nearly quantitatively removed by soil/aquifer treatment. When chlorinated, amino sugars produce low yields of regulated disinfection by-products (DBFs) but they produce significant chlorine demand that is likely caused by chlorination of free amino groups. Condensed tannins are major precursors for "blackwater" DOM such as that found in the Suwannee River. This DOM produces high yields of DBPs upon chorination, and is efficiently removed by coagulation/flocculation treatment. Terpenoid-derived DOM appears to be biologically refractory, infiltrates readily into groundwater with little removal by soil/aquifer treatment, gives low DBF-yields upon chlorination and is poorly removed by coagulation/flocculation treatments. Peptides derived from proteins are major components of the base DOM fraction (10% or less of the mass of DOM), and this fraction produces large yields of haloacetonitriles upon chorination.

  19. Organ sales needn't be exploitative (but it matters if they are).

    PubMed

    Lawlor, Rob

    2011-06-01

    This paper considers two arguments that are common in the literature on organ sales. First, organ sales are exploitative and therefore should not be permitted. Second, it doesn't matter whether organ sales are exploitative or not; the only thing that matters is that we do what is in the interests of those who need to be protected. In this paper, I argue that both of these arguments are too simplistic. My intention, however, is not to argue for or against organ sales. My conclusion, rather, is simply that we cannot hope to address the issue of organ sales if we lack a good understanding of exploitation. We should not attempt to answer the question of whether or not organ sales should be banned on the grounds that they are exploitative without acknowledging and addressing the nuances involved in understanding exploitation.

  20. Persistence of soil organic matter in eroding versus depositional landform positions

    USGS Publications Warehouse

    Berhe, Asmeret Asefaw; Harden, Jennifer W.; Torn, Margaret S.; Kleber, Markus; Burton, Sarah D.; Harte, John

    2012-01-01

    Soil organic matter (SOM) processes in dynamic landscapes are strongly influenced by soil erosion and sedimentation. We determined the contribution of physical isolation of organic matter (OM) inside aggregates, chemical interaction of OM with soil minerals, and molecular structure of SOM in controlling storage and persistence of SOM in different types of eroding and depositional landform positions. By combining density fractionation with elemental and spectroscopic analyses, we showed that SOM in depositional settings is less transformed and better preserved than SOM in eroding landform positions. However, which environmental factors exert primary control on storage and persistence of SOM depended on the nature of the landform position considered. In an annual grassland watershed, protection of SOM by physical isolation inside aggregates and chemical association of organic matter (complexation) with soil minerals, as assessed by correlation with radiocarbon concentration, were more effective in the poorly drained, lowest-lying depositional landform positions, compared to well-drained landform positions in the upper parts of the watershed. Results of this study demonstrated that processes of soil erosion and deposition are important mechanisms of long-term OM stabilization.

  1. Is organic matter found in glaciers similar to soil organic matter? A detailed molecular-level investigation of organic matter found in cryoconite holes on the Athabasca Glacier

    NASA Astrophysics Data System (ADS)

    Simpson, M. J.; Xu, Y.; Eyles, N.; Simpson, A. J.; Baer, A.

    2009-04-01

    Cryoconite is a dark-coloured, dust-like material found on the surfaces of glaciers. Cryoconite has received much interest recently because cryoconite holes, which are produced by accelerated ice melt, act as habitats for microbes on glacier surfaces and accelerate ice melt. To the best of our knowledge, cyroconite organic matter (COM) has not yet been chemically characterized at the molecular level. In this study, organic matter biomarkers and a host of Nuclear Magnetic Resonance (NMR) techniques were used to characterize COM from the Athabasca Glacier in the Canadian Rocky Mountains. The research questions that were targeted by this study include: 1) what are the sources of COM on the Athabasca Glacier; 2) are there any biomarker and/or NMR evidence for microbial community activity in the cryoconite holes; and 3) is the COM structurally similar to terrestrial OM? Solvent extracts contained large quantities of fatty acids, n-alkanols, n-alkanes, wax esters and sterols. A large contribution of C23, C25 and C27 relative to C29 and C31 n-alkanes suggests that allochthonous COM is mainly from lower order plants (mosses, lichens). This is confirmed by the absence of lignin phenols (after copper (II) oxidation) in extracts and NMR analyses of COM. Solution-state 1H NMR reveals prominent signals from microbial components, while solid-state 13C Cross Polarization Magic Angle Spinning NMR analysis shows an atypically high alkyl/O-alkyl ratio, suggesting that COM is unique compared to organic matter found in nearby soils. The NMR results suggest that COM is dominated by microbial-derived compounds which were confirmed by phospholipid fatty acid analysis, which showed a significant microbial contribution, primarily from bacteria and minor microeukaryotes. Both biomarker and NMR data suggest that COM likely supports active microbial communities on the Athabasca Glacier and that COM composition is uniquely different than that found in terrestrial environments. Our data

  2. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    USGS Publications Warehouse

    Kirwanm, M.L.; Langley, J.A.; Guntenspergen, Gleen R.; Megonigal, J.P.

    2013-01-01

    The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

  3. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    NASA Astrophysics Data System (ADS)

    Kirwan, M. L.; Langley, J. A.; Guntenspergen, G. R.; Megonigal, J. P.

    2013-03-01

    The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

  4. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    NASA Astrophysics Data System (ADS)

    Kirwan, M. L.; Langley, J. A.; Guntenspergen, G. R.; Megonigal, J. P.

    2012-10-01

    The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

  5. Organic Matter Detection on Mars by Pyrolysis-FTIR: An Analysis of Sensitivity and Mineral Matrix Effects.

    PubMed

    Gordon, Peter R; Sephton, Mark A

    2016-11-01

    Returning samples from Mars will require an effective method to assess and select the highest-priority geological materials. The ideal instrument for sample triage would be simple in operation, limited in its demand for resources, and rich in produced diagnostic information. Pyrolysis-Fourier infrared spectroscopy (pyrolysis-FTIR) is a potentially attractive triage instrument that considers both the past habitability of the sample depositional environment and the presence of organic matter that may reflect actual habitation. An important consideration for triage protocols is the sensitivity of the instrumental method. Experimental data indicate pyrolysis-FTIR sensitivities for organic matter at the tens of parts per million level. The mineral matrix in which the organic matter is hosted also has an influence on organic detection. To provide an insight into matrix effects, we mixed well-characterized organic matter with a variety of dry minerals, to represent the various inorganic matrices of Mars samples, prior to analysis. During pyrolysis-FTIR, serpentinites analogous to those on Mars indicative of the Phyllocian Era led to no negative effects on organic matter detection; sulfates analogous to those of the Theiikian Era led, in some instances, to the combustion of organic matter; and palagonites, which may represent samples from the Siderikian Era, led, in some instances, to the chlorination of organic matter. Any negative consequences brought about by these mineral effects can be mitigated by the correct choice of thermal extraction temperature. Our results offer an improved understanding of how pyrolysis-FTIR can perform during sample triage on Mars. Key Words: Mars-Life-detection instruments-Search for Mars' organics-Biosignatures. Astrobiology 16, 831-845.

  6. Studying of shale organic matter structure and pore space transformations during hydrocarbon generation

    NASA Astrophysics Data System (ADS)

    Giliazetdinova, Dina; Korost, Dmitry; Gerke, Kirill

    2016-04-01

    Due to the increased interest in the study of the structure, composition, and oil and gas potential of unconventional hydrocarbon resources, investigations of the transformation of the pore space of rocks and organic matter alterations during the generation of hydrocarbon fluids are getting attention again. Due to the conventional hydrocarbon resources decreasing, there will be a necessity to develop new unconventional hydrocarbon resources. Study of the conditions and processes of hydrocarbon generation, formation and transformation of the pore space in these rocks is pivotal to understand the mechanisms of oil formation and determine the optimal and cost effective ways for their industrial exploration. In this study, we focus on organic matter structure and its interaction with the pore space of shales during hydrocarbon generation and report some new results. Collected rock samples from Domanic horizon of South-Tatar arch were heated in the pyrolyzer to temperatures closely corresponding to different catagenesis stages. X-ray microtomography method and SEM were used to monitor changes in the morphology of the pore space and organic matter structure within studied shale rocks. By routine measurements we made sure that all samples (10 in total) had similar composition of organic and mineral phases. All samples in the collection were grouped according to initial structure and amount of organics and processed separately to: 1) study the influence of organic matter content on the changing morphology of the rock under thermal effects; 2) study the effect of initial structure on the primary migration processes for samples with similar organic matter content. An additional experiment was conducted to study the dynamics of changes in the structure of the pore space and prove the validity of our approach. At each stage of heating the morphology of altered rocks was characterized by formation of new pores and channels connecting primary voids. However, it was noted that

  7. Labile and recalcitrant organic matter utilization by river biofilm under increasing water temperature.

    PubMed

    Ylla, Irene; Romaní, Anna M; Sabater, Sergi

    2012-10-01

    Microbial biofilms in rivers contribute to the decomposition of the available organic matter which typically shows changes in composition and bioavailability due to their origin, seasonality, and watershed characteristics. In the context of global warming, enhanced biofilm organic matter decomposition would be expected but this effect could be specific when either a labile or a recalcitrant organic matter source would be available. A laboratory experiment was performed to mimic the effect of the predicted increase in river water temperature (+4 °C above an ambient temperature) on the microbial biofilm under differential organic matter sources. The biofilm microbial community responded to higher water temperature by increasing bacterial cell number, respiratory activity (electron transport system) and microbial extracellular enzymes (extracellular enzyme activity). At higher temperature, the phenol oxidase enzyme explained a large fraction of respiratory activity variation suggesting an enhanced microbial use of degradation products from humic substances. The decomposition of hemicellulose (β-xylosidase activity) seemed to be also favored by warmer conditions. However, at ambient temperature, the enzymes highly responsible for respiration activity variation were β-glucosidase and leu-aminopeptidase, suggesting an enhanced microbial use of polysaccharides and peptides degradation products. The addition of labile dissolved organic carbon (DOC; dipeptide plus cellobiose) caused a further augmentation of heterotrophic biomass and respiratory activity. The changes in the fluorescence index and the ratio Abs(250)/total DOC indicated that higher temperature accelerated the rates of DOC degradation. The experiment showed that the more bioavailable organic matter was rapidly cycled irrespective of higher temperature while degradation of recalcitrant substances was enhanced by warming. Thus, pulses of carbon at higher water temperature might have consequences for DOC

  8. Preservation of overmature, ancient, sedimentary organic matter in carbonate concretions during outcrop weathering.

    PubMed

    Loyd, S J

    2017-01-01

    Concretions are preferentially cemented zones within sediments and sedimentary rocks. Cementation can result from relatively early diagenetic processes that include degradation of sedimentary organic compounds or methane as indicated by significantly 13 C-depleted or enriched carbon isotope compositions. As minerals fill pore space, reduced permeability may promote preservation of sediment components from degradation during subsequent diagenesis, burial heating and outcrop weathering. Discrete and macroscopic organic remains, macro and microfossils, magnetic grains, and sedimentary structures can be preferentially preserved within concretions. Here, Cretaceous carbonate concretions of the Holz Shale are shown to contain relatively high carbonate-free total organic carbon (TOC) contents (up to ~18.5 wt%) compared to the surrounding host rock (with <2.1 wt%). TOC increases with total inorganic carbon (TIC) content, a metric of the degree of cementation. Pyrite contents within concretions generally correlate with organic carbon contents. Concretion carbonate carbon isotope compositions (δ 13 C carb ) range from -22.5 to -3.4‰ (VPDB) and do not correlate strongly with TOC. Organic carbon isotope compositions (δ 13 C org ) of concretions and host rock are similar. Thermal maturity data indicate that both host and concretion organic matter are overmature and have evolved beyond the oil window maturity stage. Although the organic matter in general has experienced significant oxidative weathering, concretion interiors exhibit lower oxygen indices relative to the host. These results suggest that carbonate concretions can preferentially preserve overmature, ancient, sedimentary organic matter during outcrop weathering, despite evidence for organic matter degradation genetic mechanisms. As a result, concretions may provide an optimal proxy target for characterization of more primary organic carbon concentrations and chemical compositions. In addition, these findings

  9. Impacts of heterogeneous organic matter on phenanthrene sorption--Different soil and sediment samples

    USGS Publications Warehouse

    Karapanagioti, Hrissi K.; Childs, Jeffrey; Sabatini, David A.

    2001-01-01

    Organic petrography has been proposed as a tool for characterizing the heterogeneous organic matter present in soil and sediment samples. A new simplified method is proposed as a quantitative means of interpreting observed sorption behavior for phenanthrene and different soils and sediments based on their organic petrographical characterization. This method is tested under singe solute conditions and at phenanthrene concentration of 1 μg/L. Since the opaque organic matter fraction dominates the sorption process, we propose that by quantifying this fraction one can interpret organic content normalized sorption distribution coefficient (Koc) values for a sample. While this method was developed and tested for various samples within the same aquifer, in the current study the method is validated for soil and sediment samples from different sites that cover a wide range of organic matter origin, age, and organic content. All 10 soil and sediment samples studied had log Koc values for the opaque particles between 5.6 and 6.8. This range of Koc values illustrates the heterogeneity of opaque particles between sites and geological formations and thus the need to characterize the opaque fraction of materials on a site-by-site basis.

  10. Plants Regulate Soil Organic Matter Decomposition in Response to Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Megonigal, P.; Mueller, P.; Jensen, K.

    2014-12-01

    Tidal wetlands have a large capacity for producing and storing organic matter, making their role in the global carbon budget disproportionate to their land area. Most of the organic matter stored in these systems is in soils where it contributes 2-5 times more to surface accretion than an equal mass of minerals. Soil organic matter (SOM) sequestration is the primary process by which tidal wetlands become perched high in the tidal frame, decreasing their vulnerability to accelerated sea level rise. Plant growth responses to sea level rise are well understood and represented in century-scale forecast models of soil surface elevation change. We understand far less about the response of soil organic matter decomposition to rapid sea level rise. Here we quantified the effects of sea level on SOM decomposition rates by exposing planted and unplanted tidal marsh monoliths to experimentally manipulated flood duration. The study was performed in a field-based mesocosm facility at the Smithsonian's Global Change Research Wetland. SOM decomposition rate was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated with a two end-member δ13C-CO2 model. Despite the dogma that decomposition rates are inversely related to flooding, SOM mineralization was not sensitive to flood duration over a 35 cm range in soil surface elevation. However, decomposition rates were strongly and positively related to aboveground biomass (R2≥0.59, p≤0.01). We conclude that soil carbon loss through decomposition is driven by plant responses to sea level in this intensively studied tidal marsh. If this result applies more generally to tidal wetlands, it has important implications for modeling soil organic matter and surface elevation change in response to accelerated sea level rise.

  11. Fifteen years of PARAFAC application to organic matter fluorescence - progress, problems and possibilities

    NASA Astrophysics Data System (ADS)

    Murphy, K.; Stedmon, C. A.; Wunsch, U.

    2017-12-01

    The study of dissolved organic matter in aquatic milieu frequently involves measuring and interpreting fluorescence excitation emission matrices (EEMs) as a proxy for studying the total organic matter pool. Parallel Factor Analysis (PARAFAC) is used widely to identify and track independent organic matter fractions. This approach assumes that each EEM reflects the combined fluorescence signal from a limited number of unique, non-interacting chemical components, which are determined via a fitting algorithm. During the past fifteen years, considerable progress in understanding dissolved organic matter fluorescence has been achieved with the aid of PARAFAC; however, very few identical or ubiquitous fluorescence spectra have been independently identified. We studied the influence of wavelength selection on PARAFAC models and found this factor to have a decisive impact on PARAFAC spectra despite receiving little attention in most studies. Because large, chemically-diverse datasets may be too complex to analyse with PARAFAC, we are exploring novel methods for increasing variability in small datasets in order to reduce biases and increase interpretability. Our results suggest that spectral variability in PARAFAC models between studies are in many cases due to artefacts that could be minimised by careful experimental and modelling approaches.

  12. Organic speciation of size-segregated atmospheric particulate matter

    NASA Astrophysics Data System (ADS)

    Tremblay, Raphael

    Particle size and composition are key factors controlling the impacts of particulate matter (PM) on human health and the environment. A comprehensive method to characterize size-segregated PM organic content was developed, and evaluated during two field campaigns. Size-segregated particles were collected using a cascade impactor (Micro-Orifice Uniform Deposit Impactor) and a PM2.5 large volume sampler. A series of alkanes and polycyclic aromatic hydrocarbons (PAHs) were solvent extracted and quantified using a gas chromatograph coupled with a mass spectrometer (GC/MS). Large volume injections were performed using a programmable temperature vaporization (PTV) inlet to lower detection limits. The developed analysis method was evaluated during the 2001 and 2002 Intercomparison Exercise Program on Organic Contaminants in PM2.5 Air Particulate Matter led by the US National Institute of Standards and Technology (NIST). Ambient samples were collected in May 2002 as part of the Tampa Bay Regional Atmospheric Chemistry Experiment (BRACE) in Florida, USA and in July and August 2004 as part of the New England Air Quality Study - Intercontinental Transport and Chemical Transformation (NEAQS - ITCT) in New Hampshire, USA. Morphology of the collected particles was studied using scanning electron microscopy (SEM). Smaller particles (one micrometer or less) appeared to consist of solid cores surrounded by a liquid layer which is consistent with combustion particles and also possibly with particles formed and/or coated by secondary material like sulfate, nitrate and secondary organic aerosols. Source apportionment studies demonstrated the importance of stationary sources on the organic particulate matter observed at these two rural sites. Coal burning and biomass burning were found to be responsible for a large part of the observed PAHs during the field campaigns. Most of the measured PAHs were concentrated in particles smaller than one micrometer and linked to combustion sources

  13. Characterization and Phenanthrene Sorption of Natural and Pyrogenic Organic Matter Fractions.

    PubMed

    Jin, Jie; Sun, Ke; Wang, Ziying; Yang, Yan; Han, Lanfang; Xing, Baoshan

    2017-03-07

    Pyrogenic humic acid (HA) is released into the environment during the large-scale application of biochar. However, the biogeochemistry of pyrogenic organic matter (PyOM) fractions and their sorption of hydrophobic organic compounds (HOCs) are poorly understood in comparison with natural organic matter (NOM) fractions. HA and humin (HM) fractions isolated from soils and the oxidized biochars were characterized. Sorption of phenanthrene (PHE) by these fractions was also examined. The characterization results demonstrate that pyrogenic HAs are different from natural HAs, with the former having lower atomic H/C ratios, more abundant aromatic C, and higher concentrations of surface carboxylic groups. Compared with the fresh biochars, the K oc of PHE on their oxidized biochars, pyrogenic HA, and HM fractions were undiminished, which is encouraging for the use of biochar in soil remediation. The PyOM fractions exhibited stronger nonlinear sorption than the NOM fractions. In addition, the PyOM fractions had higher sorption capacity than the NOM fractions due to their low polar C content and high aryl C content. The results obtained from this work will shed new light on the impact of the addition of biochar on the biogeochemistry of soil organic matter and on the fate of HOCs in biochar-amended soil.

  14. Sea cucumbers reduce chromophoric dissolved organic matter in aquaculture tanks.

    PubMed

    Sadeghi-Nassaj, Seyed Mohammad; Catalá, Teresa S; Álvarez, Pedro A; Reche, Isabel

    2018-01-01

    Mono-specific aquaculture effluents contain high concentrations of nutrients and organic matter, which affect negatively the water quality of the recipient ecosystems. A fundamental feature of water quality is its transparency. The fraction of dissolved organic matter that absorbs light is named chromophoric dissolved organic matter (CDOM). A sustainable alternative to mono-specific aquaculture is the multitrophic aquaculture that includes species trophically complementary named "extractive" species that uptake the waste byproducts. Sea cucumbers are recognized as efficient extractive species due to the consumption of particulate organic matter (POM). However, the effects of sea cucumbers on CDOM are still unknown. During more than one year, we monitored CDOM in two big-volume tanks with different trophic structure. One of the tanks (-holothurian) only contained around 810 individuals of Anemonia sulcata , whereas the other tank (+holothurian) also included 90 individuals of Holothuria tubulosa and Holothuria forskali . We routinely analyzed CDOM absorption spectra and determined quantitative (absorption coefficients at 325 nm) and qualitative (spectral slopes) optical parameters in the inlet waters, within the tanks, and in their corresponding effluents. To confirm the time-series results, we also performed three experiments. Each experiment consisted of two treatments: +holothurians (+H) and -holothurians (-H). We set up three +H tanks with 80 individuals of A. sulcata and 10 individuals of H. tubulosa in each tank and four -H tanks that contained only 80 individuals of A. sulcata . In the time-series, absorption coefficients at 325 nm ( a 325 ) and spectral slopes from 275 to 295 nm ( S 275-295 ) were significantly lower in the effluent of the +holothurian tank (average: 0.33 m -1 and 16 µm -1 , respectively) than in the effluent of the -holothurian tank (average: 0.69 m -1 and 34 µm -1 , respectively), the former being similar to those found in the inlet

  15. Early diagenesis of organic matter in a Sawgrass peat from the Everglades, Florida

    USGS Publications Warehouse

    Orem, W.H.; Hatcher, P.G.

    1987-01-01

    The transformation of plant biopolymers to humic substances in peats during early diagenesis is a critical but poorly understood step in the formation of coal. This paper presents results concerning the structural interrelationships among various fractions of the organic matter in peat and the dissolved organic matter in the pore water from a site in The Everglades, relying primarily on elemental analysis and 13C nuclear magnetic resonance for structural elucidation. Our goal was to obtaine some insight into the sequence of steps involved in the formation of humic substances. Results show that the major change occurring in the whole peat during diagenesis is loss of carbohydrates. The components of the peat which are more resistant to microbial degradation become concentrated in the humin fraction. This resistant fraction of the organic matter includes aliphatic and aromatic components. The aromatic components are thought to be derived from lignin while the aliphatic moieties may represent decomposed algal remains. The carbohydrates lost from the whole peat appear to be concentrated in the fulvic acids and the dissolved organic matter in the pore water. The humic acids consist predominantly of aromatic and aliphatic structures, and may represent partially degraded lignin-like structures and aliphatic compounds from algae. The data presented here suggest that humic and fulvic acids are the partially degraded fractions of the peat while the humin contains the resistant or preserved portion of the organic matter. The proposition that humic substances are formed by the condensation of amino acids and sugars is not supported by the results of this study. ?? 1987.

  16. Properties and reactivity of aquatic organic matter from an Amazonian floodplain system

    NASA Astrophysics Data System (ADS)

    Perez, M. A. P.; Benedetti, M. F.; Moreira-Turcq, P.

    2009-04-01

    The aim of this study was to characterize the nature of the bulk dissolved organic matter (DOM) in different types of environments in the Amazon River-floodplain system and determine the importance of two different fractions of dissolved organic matter onto adsorption processes that occurs through the transport of organic matter in the Amazon Basin. Seven samples were collected in the Amazon River - "Lago Grande de Curuai" floodplain system, in rising water levels cruise (March 2006). The samples were taken in the Amazon main stem, in white and black floodplain waters, and in the middle of a phytoplaktonic bloom. The bulk, dissolved (i.e. < 0.22 micrometer), hydrophobic (HPO) and transphilic (TPH) fractions extracted by XAD-8 and XAD-4 columns chromatography respectively were isolated. Organic carbon (OC) and total nitrogen (TN) concentrations, Specific UV absorbance (SUVA), Size-Exclusion Chromatography (SEC), d13C and d15N isotopes, and reactivity (acid-base titration) were characterized for these fractions. Adsorption experiments onto mineral phase from de surface sediment of the Curuai floodplain lake (rich in smectite and kaolinite) were realized with HPO and TPH fractions. The OC concentrations in the natural organic matter (Bulk and < 0.22 micrometer fractions) varied between 3.7-5.7 mg/L. The OC and TN concentrations varied between 510 - 528 mg C/g in the HPO fraction, and 408 - 462 mg C/g in the TPH compounds and between 14.3 - 17.6 mg N/g (HPO), and 22.1 - 30.0 mg N/g (TPH). The molecular weight of both fractions (HPO and TPH) didn't present significant variation. Both fractions presented high aromaticity and they were rich in carboxylic groups, although smaller values are systematically reported for the HPO fractions. The OM of the main stem was the most adsorbed, followed by the white water lake, the phytoplanktonic bloom, and black water lake sample. These results helped us to strengthen the hypothesis that the organic matter carried from the river and

  17. Controls on the distribution of fluorescent dissolved organic matter during an under‐ice algal bloom in the western Arctic Ocean

    PubMed Central

    Weiss, Elliot L.; Schieber, Brian; Greg Mitchell, B.

    2017-01-01

    Abstract In this study we used fluorescence excitation and emission matrix spectroscopy, hydrographic data, and a self‐organizing map (SOM) analysis to assess the spatial distribution of labile and refractory fluorescent dissolved organic matter (FDOM) for the Chukchi and Beaufort Seas at the time of a massive under‐ice phytoplankton bloom during early summer 2011. Biogeochemical properties were assessed through decomposition of water property classes and sample classification that employed a SOM neural network‐based analysis which classified 10 clusters from 269 samples and 17 variables. The terrestrial, humic‐like component FDOM (ArC1, 4.98 ± 1.54 Quinine Sulfate Units (QSU)) and protein‐like component FDOM (ArC3, 1.63 ± 0.88 QSU) were found to have elevated fluorescence in the Lower Polar Mixed Layer (LPML) (salinity ~29.56 ± 0.76). In the LPML water mass, the observed contribution of meteoric water fraction was 17%, relative to a 12% contribution from the sea ice melt fraction. The labile ArC3‐protein‐like component (2.01 ± 1.92 QSU) was also observed to be elevated in the Pacific Winter Waters mass, where the under‐ice algal bloom was observed (~40–50 m). We interpreted these relationships to indicate that the accumulation and variable distribution of the protein‐like component on the shelf could be influenced directly by sea ice melt, transport, and mixing processes and indirectly by the in situ algal bloom and microbial activity. ArC5, corresponding to what is commonly considered marine humic FDOM, indicated a bimodal distribution with high values in both the freshest and saltiest waters. The association of ArC5 with deep, dense salty water is consistent with this component as refractory humic‐like FDOM, whereas our evidence of a terrestrial origin challenges this classic paradigm for this component. PMID:28989231

  18. Controls on the distribution of fluorescent dissolved organic matter during an under-ice algal bloom in the western Arctic Ocean.

    PubMed

    Mendoza, Wilson G; Weiss, Elliot L; Schieber, Brian; Greg Mitchell, B

    2017-07-01

    In this study we used fluorescence excitation and emission matrix spectroscopy, hydrographic data, and a self-organizing map (SOM) analysis to assess the spatial distribution of labile and refractory fluorescent dissolved organic matter (FDOM) for the Chukchi and Beaufort Seas at the time of a massive under-ice phytoplankton bloom during early summer 2011. Biogeochemical properties were assessed through decomposition of water property classes and sample classification that employed a SOM neural network-based analysis which classified 10 clusters from 269 samples and 17 variables. The terrestrial, humic-like component FDOM (ArC1, 4.98 ± 1.54 Quinine Sulfate Units (QSU)) and protein-like component FDOM (ArC3, 1.63 ± 0.88 QSU) were found to have elevated fluorescence in the Lower Polar Mixed Layer (LPML) (salinity ~29.56 ± 0.76). In the LPML water mass, the observed contribution of meteoric water fraction was 17%, relative to a 12% contribution from the sea ice melt fraction. The labile ArC3-protein-like component (2.01 ± 1.92 QSU) was also observed to be elevated in the Pacific Winter Waters mass, where the under-ice algal bloom was observed (~40-50 m). We interpreted these relationships to indicate that the accumulation and variable distribution of the protein-like component on the shelf could be influenced directly by sea ice melt, transport, and mixing processes and indirectly by the in situ algal bloom and microbial activity. ArC5, corresponding to what is commonly considered marine humic FDOM, indicated a bimodal distribution with high values in both the freshest and saltiest waters. The association of ArC5 with deep, dense salty water is consistent with this component as refractory humic-like FDOM, whereas our evidence of a terrestrial origin challenges this classic paradigm for this component.

  19. Extraterrestrial organic matter: a review

    NASA Technical Reports Server (NTRS)

    Irvine, W. M.

    1998-01-01

    We review the nature of the widespread organic material present in the Milky Way Galaxy and in the Solar System. Attention is given to the links between these environments and between primitive Solar System objects and the early Earth, indicating the preservation of organic material as an interstellar cloud collapsed to form the Solar System and as the Earth accreted such material from asteroids, comets and interplanetary dust particles. In the interstellar medium of the Milky Way Galaxy more than 100 molecular species, the bulk of them organic, have been securely identified, primarily through spectroscopy at the highest radio frequencies. There is considerable evidence for significantly heavier organic molecules, particularly polycyclic aromatics, although precise identification of individual species has not yet been obtained. The so-called diffuse interstellar bands are probably important in this context. The low temperature kinetics in interstellar clouds leads to very large isotopic fractionation, particularly for hydrogen, and this signature is present in organic components preserved in carbonaceous chondritic meteorites. Outer belt asteroids are the probable parent bodies of the carbonaceous chondrites, which may contain as much as 5% organic material, including a rich variety of amino acids, purines, pyrimidines, and other species of potential prebiotic interest. Richer in volatiles and hence less thermally processed are the comets, whose organic matter is abundant and poorly characterized. Cometary volatiles, observed after sublimation into the coma, include many species also present in the interstellar medium. There is evidence that most of the Earth's volatiles may have been supplied by a 'late' bombardment of comets and carbonaceous meteorites, scattered into the inner Solar System following the formation of the giant planets. How much in the way of intact organic molecules of potential prebiotic interest survived delivery to the Earth has become an

  20. Contributions of organic and inorganic matter to sediment volume and accretion in tidal wetlands at steady state

    PubMed Central

    Barber, Donald C.; Callaway, John C.; Chambers, Randy; Hagen, Scott C.; Hopkinson, Charles S.; Johnson, Beverly J.; Megonigal, Patrick; Neubauer, Scott C.; Troxler, Tiffany; Wigand, Cathleen

    2016-01-01

    Abstract A mixing model derived from first principles describes the bulk density (BD) of intertidal wetland sediments as a function of loss on ignition (LOI). The model assumes that the bulk volume of sediment equates to the sum of self‐packing volumes of organic and mineral components or BD = 1/[LOI/k1 + (1‐LOI)/k2], where k1 and k2 are the self‐packing densities of the pure organic and inorganic components, respectively. The model explained 78% of the variability in total BD when fitted to 5075 measurements drawn from 33 wetlands distributed around the conterminous United States. The values of k1 and k2 were estimated to be 0.085 ± 0.0007 g cm−3 and 1.99 ± 0.028 g cm−3, respectively. Based on the fitted organic density (k1) and constrained by primary production, the model suggests that the maximum steady state accretion arising from the sequestration of refractory organic matter is ≤ 0.3 cm yr−1. Thus, tidal peatlands are unlikely to indefinitely survive a higher rate of sea‐level rise in the absence of a significant source of mineral sediment. Application of k2 to a mineral sediment load typical of East and eastern Gulf Coast estuaries gives a vertical accretion rate from inorganic sediment of 0.2 cm yr−1. Total steady state accretion is the sum of the parts and therefore should not be greater than 0.5 cm yr−1 under the assumptions of the model. Accretion rates could deviate from this value depending on variation in plant productivity, root:shoot ratio, suspended sediment concentration, sediment‐capture efficiency, and episodic events. PMID:27819012

  1. Organic Matter Detection on Mars by Pyrolysis-FTIR: An Analysis of Sensitivity and Mineral Matrix Effects

    PubMed Central

    Gordon, Peter R.

    2016-01-01

    Abstract Returning samples from Mars will require an effective method to assess and select the highest-priority geological materials. The ideal instrument for sample triage would be simple in operation, limited in its demand for resources, and rich in produced diagnostic information. Pyrolysis–Fourier infrared spectroscopy (pyrolysis-FTIR) is a potentially attractive triage instrument that considers both the past habitability of the sample depositional environment and the presence of organic matter that may reflect actual habitation. An important consideration for triage protocols is the sensitivity of the instrumental method. Experimental data indicate pyrolysis-FTIR sensitivities for organic matter at the tens of parts per million level. The mineral matrix in which the organic matter is hosted also has an influence on organic detection. To provide an insight into matrix effects, we mixed well-characterized organic matter with a variety of dry minerals, to represent the various inorganic matrices of Mars samples, prior to analysis. During pyrolysis-FTIR, serpentinites analogous to those on Mars indicative of the Phyllocian Era led to no negative effects on organic matter detection; sulfates analogous to those of the Theiikian Era led, in some instances, to the combustion of organic matter; and palagonites, which may represent samples from the Siderikian Era, led, in some instances, to the chlorination of organic matter. Any negative consequences brought about by these mineral effects can be mitigated by the correct choice of thermal extraction temperature. Our results offer an improved understanding of how pyrolysis-FTIR can perform during sample triage on Mars. Key Words: Mars—Life-detection instruments—Search for Mars’ organics—Biosignatures. Astrobiology 16, 831–845. PMID:27870586

  2. Soil organic matter regulates molybdenum storage and mobility in forests

    USGS Publications Warehouse

    Marks, Jade A; Perakis, Steven; King, Elizabeth K.; Pett-Ridge, Julie

    2015-01-01

    The trace element molybdenum (Mo) is essential to a suite of nitrogen (N) cycling processes in ecosystems, but there is limited information on its distribution within soils and relationship to plant and bedrock pools. We examined soil, bedrock, and plant Mo variation across 24 forests spanning wide soil pH gradients on both basaltic and sedimentary lithologies in the Oregon Coast Range. We found that the oxidizable organic fraction of surface mineral soil accounted for an average of 33 %of bulk soil Mo across all sites, followed by 1.4 % associated with reducible Fe, Al, and Mn-oxides, and 1.4 % in exchangeable ion form. Exchangeable Mo was greatest at low pH, and its positive correlation with soil carbon (C) suggests organic matter as the source of readily exchangeable Mo. Molybdenum accumulation integrated over soil profiles to 1 m depth (τMoNb) increased with soil C, indicating that soil organic matter regulates long-term Mo retention and loss from soil. Foliar Mo concentrations displayed no relationship with bulk soil Mo, and were not correlated with organic horizon Mo or soil extractable Mo, suggesting active plant regulation of Mo uptake and/or poor fidelity of extractable pools to bioavailability. We estimate from precipitation sampling that atmospheric deposition supplies, on average, over 10 times more Mo annually than does litterfall to soil. In contrast, bedrock lithology had negligible effects on foliar and soil Mo concentrations and on Mo distribution among soil fractions. We conclude that atmospheric inputs may be a significant source of Mo to forest ecosystems, and that strong Mo retention by soil organic matter limits ecosystem Mo loss via dissolution and leaching pathways.

  3. Roles of epi-anecic taxa of earthworms in the organic matter recycling

    NASA Astrophysics Data System (ADS)

    Hoeffner, Kevin; Monard, Cécile; Santonja, Mathieu; Pérès, Guénola; Cluzeau, Daniel

    2017-04-01

    Given their impact on soil functioning and their interactions with soil organisms, earthworms contribute to the recycling of organic matter and participate significantly in the numerous ecosystem services provided by soils. Most studies on the role of earthworms in organic matter recycling were conducted at the level of the four functional groups (epigeic, epi-anecic, anecic strict and endogeic), but their effects at taxa level remain largely unknown. Still, within a functional group, anatomic and physiologic earthworm taxa traits are different, which should impact organic matter recycling. This study aims at determining, under controlled conditions, epi-anecic taxa differences in (i) leaf litter mass loss, (ii) assimilation and (iii) impact on microorganisms communities implied in organic matter degradation. In seperate microcosms, we chose 4 epi anecic taxa (Lumbricus rubellus, Lumbricus festivus, Lumbricus centralis and Lumbricus terrestris). Each taxon was exposed separately to leaves of three different plants (Holcus lanatus, Lolium perenne and Corylus avellana). In the same microcosm, leaves of each plant was both placed on the surface and buried 10cm deep. The experiment lasted 10 days for half of the samples and 20 days for the second half. Microorganisms communities were analysed using TRFLP in each earthworm taxon burrow walls at 20 days. We observed differences between epi-anecic taxa depending on species of plant and the duration of the experiment. Results are discussed taking into account physical and chemical properties of these 3 trophic resources (e.g. C/N ratio, phenolic compounds, percentage of lignin and cellulose...).

  4. Organic Matter and Water Addition Enhance Soil Respiration in an Arid Region

    PubMed Central

    Lai, Liming; Wang, Jianjian; Tian, Yuan; Zhao, Xuechun; Jiang, Lianhe; Chen, Xi; Gao, Yong; Wang, Shaoming; Zheng, Yuanrun

    2013-01-01

    Climate change is generally predicted to increase net primary production, which could lead to additional C input to soil. In arid central Asia, precipitation has increased and is predicted to increase further. To assess the combined effects of these changes on soil CO2 efflux in arid land, a two factorial manipulation experiment in the shrubland of an arid region in northwest China was conducted. The experiment used a nested design with fresh organic matter and water as the two controlled parameters. It was found that both fresh organic matter and water enhanced soil respiration, and there was a synergistic effect of these two treatments on soil respiration increase. Water addition not only enhanced soil C emission, but also regulated soil C sequestration by fresh organic matter addition. The results indicated that the soil CO2 flux of the shrubland is likely to increase with climate change, and precipitation played a dominant role in regulating soil C balance in the shrubland of an arid region. PMID:24204907

  5. Pilot investigation of two-stage biofiltration for removal of natural organic matter in drinking water treatment.

    PubMed

    Fu, Jie; Lee, Wan-Ning; Coleman, Clark; Meyer, Melissa; Carter, Jason; Nowack, Kirk; Huang, Ching-Hua

    2017-01-01

    A pilot study employing two parallel trains of two-stage biofiltration, i.e., a sand/anthracite (SA) biofilter followed by a biologically-active granular activated carbon (GAC) contactor, was conducted to test the efficiency, feasibility and stability of biofiltration for removing natural organic matter (NOM) after coagulation in a drinking water treatment plant. Results showed the biofiltration process could effectively remove turbidity (<0.1 NTU in all effluents) and NOM (>24% of dissolved organic carbon (DOC), >57% of UV 254 , and >44% of SUVA 254 ), where the SA biofilters showed a strong capacity for turbidity removal, while the GAC contactors played the dominant role in NOM removal. The vertical profile of water quality in the GAC contactors indicated the middle-upper portion was the critical zone for the removal of NOM, where relatively higher adsorption and enhanced biological removal were afforded. Fluorescence excitation-emission matrix (EEM) analysis of NOM showed that the GAC contactors effectively decreased the content of humic-like component, while protein-like component was refractory for the biofiltration process. Nutrients (NH 4 -N and PO 4 -P) supplementation applied upstream of one of the two-stage biofiltration trains (called engineered biofiltration) stimulated the growth of microorganisms, and showed a modest effect on promoting the biological removal of small non-aromatic compositions in NOM. Redundancy analysis (RDA) indicated influent UV 254 was the most explanatory water quality parameter for GAC contactors' treatment performance, and a high load of UV 254 would result in significantly reduced removals of UV 254 and SUVA 254 . Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Bioavailable Carbon and the Relative Degradation State of Organic Matter in Active Layer and Permafrost Soils

    NASA Astrophysics Data System (ADS)

    Jastrow, J. D.; Burke, V. J.; Vugteveen, T. W.; Fan, Z.; Hofmann, S. M.; Lederhouse, J. S.; Matamala, R.; Michaelson, G. J.; Mishra, U.; Ping, C. L.

    2015-12-01

    The decomposability of soil organic carbon (SOC) in permafrost regions is a key uncertainty in efforts to predict carbon release from thawing permafrost and its impacts. The cold and often wet environment is the dominant factor limiting decomposer activity, and soil organic matter is often preserved in a relatively undecomposed and uncomplexed state. Thus, the impacts of soil warming and permafrost thaw are likely to depend at least initially on the genesis and past history of organic matter degradation before its stabilization in permafrost. We compared the bioavailability and relative degradation state of SOC in active layer and permafrost soils from Arctic tundra in Alaska. To assess readily bioavailable SOC, we quantified salt (0.5 M K2SO4) extractable organic matter (SEOM), which correlates well with carbon mineralization rates in short-term soil incubations. To assess the relative degradation state of SOC, we used particle size fractionation to isolate fibric (coarse) from more degraded (fine) particulate organic matter (POM) and separated mineral-associated organic matter into silt- and clay-sized fractions. On average, bulk SOC concentrations in permafrost were lower than in comparable active layer horizons. Although SEOM represented a very small proportion of the bulk SOC, this proportion was greater in permafrost than in comparable active layer soils. A large proportion of bulk SOC was found in POM for all horizons. Even for mineral soils, about 40% of bulk SOC was in POM pools, indicating that organic matter in both active layer and permafrost mineral soils was relatively undecomposed compared to typical temperate soils. Not surprisingly, organic soils had a greater proportion of POM and mineral soils had greater silt- and clay-sized carbon pools, while cryoturbated soils were intermediate. For organic horizons, permafrost organic matter was generally more degraded than in comparable active layer horizons. However, in mineral and cryoturbated horizons

  7. Highly Pristine Organic Matter in a Xenolith Clast in the Zag H Chrondrite

    NASA Technical Reports Server (NTRS)

    Kebukawa, Y.; Ito, M.; Zolensky, M. E.; Nakato, A.; Suga, H.; Takahashi, Y.; Takeichi, Y.; Mase, K.; Chan, Q.; Fries, M.; hide

    2017-01-01

    The Zag meteorite is a halite-bearing H3-6 chondrite [1]. We have been studying a dark Zag clast with abundant organic matter [2,3], which was proposed to be from Ceres [4,5]. Therefore, our systematic research of the Zag clast may provide an important linkage to the recent remote sensing observations obtained by the DAWN mission to Ceres. We prepared a new sub-sample of this clast for coordinated organic analysis by STXM-XANES and NanoSIMS, in order to understand the nature and origin of the organic matter.

  8. Physiological and biochemical responses of the Polychaete Diopatra neapolitana to organic matter enrichment.

    PubMed

    Carregosa, Vanessa; Velez, Cátia; Pires, Adília; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2014-10-01

    Several studies have demonstrated that organic matter enrichment may be associated to aquaculture, leading to impoverished benthic communities and species succession with loss of biodiversity, but very few studies have investigated biochemical and physiological alterations that species affected by aquaculture activities undergo. Thus, in the present study, the effects of the organic enrichment originating from an oyster culture were studied in the Polychaete Diopatra neapolitana, a species already shown to be sensitive to inorganic contamination. For this, physiological responses and biochemical alterations were evaluated. The results obtained revealed that individuals from highly organically enriched areas presented lower capacity to regenerate their body but higher glycogen and protein levels. Furthermore, with increasing organic matter D. neapolitana increased the lipid peroxidation (LPO), the oxidized glutathione content (GSSG) and Glutathione S-transferase activity (GSTs) content, and the activity of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD). This study evidenced that organic matter enrichment induced biochemical and physiological alterations in D. neapolitana. Thus, this species was shown to be a good sentinel species to monitor organic contamination. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Effect of aggregation on SOC transport: linking soil properties to sediment organic matter

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.

    2016-04-01

    Soils are an interface between the Earth's spheres and shaped by the nature of the interaction between them. The relevance of soil properties for the nature of the interaction between atmosphere, hydrosphere and biosphere is well-studied and accepted, on point- or ecotone-scale. However, this understanding of the largely vertical connections between spheres is not matched by a similar recognition of soil properties affecting processes acting largely in a lateral way across the land surface, such as erosion, transport and deposition of soil and the associated organic matter. Understanding the redistribution of eroded soil organic matter falls into several disciplines, most notably soil science, agronomy, hydrology and geomorphology, and recently into biogeochemistry. Accordingly, the way soil and sediment are described differs: in soil science, aggregation and structure are essential properties, while most process-based soil erosion models treat soil as a mixture of individual mineral grains, based on concepts derived in fluvial geomorphology or civil engineering. The actual behavior of aggregated sediment and the associated organic matter is not reflected by either approach and difficult to capture due to the dynamic nature of aggregation, especially in an environment such as running water. Still, a proxy to assess the uncertainties introduced by aggregation on the behavior of soil/sediment organic while moving in water across landscapes and into the aquatic system would represent a major step forward. To develop such a proxy, a database collating relevant soil, organic matter and sediment properties could serve as an initial step to identify which soil types and erosion scenarios are prone to generate a high uncertainty compared to the use of soil texture in erosion models. Furthermore, it could serve to develop standardized analytical procedures for appropriate description of soil and organic matter as sediment.

  10. Particulate organic matter predicts bacterial productivity in a river dominated estuary

    NASA Astrophysics Data System (ADS)

    Crump, B. C.

    2015-12-01

    Estuaries act as coastal filters for organic and inorganic fluvial materials in which microbial, biogeochemical, and ecological processes combine to transform organic matter and nutrients prior to export to the coastal ocean. The function of this estuarine 'bioreactor' is linked to the residence times of those materials and to rates of microbial heterotrophic activity. Our ability to forecast the impact of global change on estuarine bioreactor function requires an understanding of the basic controls on microbial community activity and diversity. In the Columbia River estuary, the microbial community undergoes a dramatic seasonal shift in species composition during which a spring bacterioplankton community, dominated by Flavobacteriaceae and Oceanospirillales, is replaced by a summer community, dominated by Rhodobacteraceae and several common marine taxa. This annual shift occurs in July, following the spring freshet, when river flow and river chlorophyll concentration decrease and when estuarine water residence time increases. Analysis of a large dataset from 17 research cruises (1990-2014) showed that the composition of particulate organic matter in the estuary changes after the freshet with decreasing organic carbon and nitrogen content, and increasing contribution of marine and autochthonous estuarine organic matter (based on PO13C and pigment ratios). Bacterial production rates (measured as leucine or thymidine incorporation rates) in the estuary respond to this change, and correlate strongly with labile particulate nitrogen concentration and temperature during individual sampling campaigns, and with the concentration of chlorophyll in the Columbia River across all seasons. Regression models suggest that the concentration of labile particulate nitrogen and the rate of bacterial production can be predicted from sensor measurements of turbidity, salinity, and temperature in the estuary and chlorophyll in the river. These results suggest that the quality of

  11. Iron oxidation stimulates organic matter decomposition in humid tropical forest soils.

    PubMed

    Hall, Steven J; Silver, Whendee L

    2013-09-01

    Humid tropical forests have the fastest rates of organic matter decomposition globally, which often coincide with fluctuating oxygen (O2 ) availability in surface soils. Microbial iron (Fe) reduction generates reduced iron [Fe(II)] under anaerobic conditions, which oxidizes to Fe(III) under subsequent aerobic conditions. We demonstrate that Fe (II) oxidation stimulates organic matter decomposition via two mechanisms: (i) organic matter oxidation, likely driven by reactive oxygen species; and (ii) increased dissolved organic carbon (DOC) availability, likely driven by acidification. Phenol oxidative activity increased linearly with Fe(II) concentrations (P < 0.0001, pseudo R(2)  = 0.79) in soils sampled within and among five tropical forest sites. A similar pattern occurred in the absence of soil, suggesting an abiotic driver of this reaction. No phenol oxidative activity occurred in soils under anaerobic conditions, implying the importance of oxidants such as O2 or hydrogen peroxide (H2 O2 ) in addition to Fe(II). Reactions between Fe(II) and H2 O2 generate hydroxyl radical, a strong nonselective oxidant of organic compounds. We found increasing consumption of H2 O2 as soil Fe(II) concentrations increased, suggesting that reactive oxygen species produced by Fe(II) oxidation explained variation in phenol oxidative activity among samples. Amending soils with Fe(II) at field concentrations stimulated short-term C mineralization by up to 270%, likely via a second mechanism. Oxidation of Fe(II) drove a decrease in pH and a monotonic increase in DOC; a decline of two pH units doubled DOC, likely stimulating microbial respiration. We obtained similar results by manipulating soil acidity independently of Fe(II), implying that Fe(II) oxidation affected C substrate availability via pH fluctuations, in addition to producing reactive oxygen species. Iron oxidation coupled to organic matter decomposition contributes to rapid rates of C cycling across humid tropical forests

  12. Urban infrastructure influences dissolved organic matter quality and bacterial metabolism in an urban stream network

    EPA Science Inventory

    Urban streams are degraded by a suite of factors, including burial beneath urban infrastructure (i.e., roads, parking lots) that eliminates light and reduces direct organic matter inputs to streams, with likely consequences for organic matter metabolism by microbes and carbon lim...

  13. The Rusty Sink: Iron Promotes the Preservation of Organic Matter in Sediments

    NASA Astrophysics Data System (ADS)

    Lalonde, K. M.; Mucci, A.; Moritz, A.; Ouellet, A.; Gelinas, Y.

    2011-12-01

    The biogeochemical cycles of iron (Fe) and organic carbon (OC) are strongly interlinked. In oceanic waters, organic ligands have been shown to control the concentration of dissolved Fe [1], whereas in soils, solid Fe phases provide a sheltering and preservative effect for organic matter [2]. Until now however, the role of iron in the preservation of OC in sediments has not been clearly established. Here we show that 21.5 ± 8.6% of the OC in sediments is directly bound to reactive iron phases, which promote the preservation of OC in sediments. Iron-bound OC represents a global mass of 19 to 45 × 10^15 g of OC in surface marine sediments. This pool of OC is different from the rest of sedimentary OC, with 13C and nitrogen-enriched organic matter preferentially bound to Fe which suggests that biochemical fractionation occurs with OC-Fe binding. Preferential binding also affects the recovery of high molecular weight lipid biomarkers and acidic lignin oxidation products, changing the environmental message of proxies derived from these biomarkers. [1] Johnson, K. S., Gordon, R. M. & Coale, K. H. What controls dissolved iron in the world ocean? Marine Chemistry 57, 137-161 (1997). [2] Kaiser, K. & Guggenberger, G. The role of DOM sorption to mineral surfaces in the preservation of organic matter in soils. Organic Geochemistry 31, 711-725 (2000).

  14. Quenching and Sensitizing Fullerene Photoreactions by Natural Organic Matter

    EPA Science Inventory

    Effects of natural organic matter (NOM) on the photoreaction kinetics of fullerenes (i.e., C60 and fullerenol) were investigated using simulated sunlight and monochromatic radiation (365 nm). NOM from several sources quenched (slowed) the photoreaction of C60 aggregates in water ...

  15. Advanced solid-state NMR spectroscopy of natural organic matter

    USDA-ARS?s Scientific Manuscript database

    Solid-state NMR is essential for the characterization of natural organic matter (NOM) and is gaining importance in geosciences and environmental sciences. This review is intended to highlight advanced solid-state NMR techniques, especially the systematic approach to NOM characterization, and their ...

  16. Impact of Urbanisation on Soil Organic Matter Content in chernozems in Vojvodina region

    NASA Astrophysics Data System (ADS)

    Samardžić, Miljan; Vasin, Jovica; Jajić, Igor; Vasenev, Ivan

    2017-04-01

    Vojvodina is the northern province of Serbia and the chief agricultural centre of the country. The main soil type in Vojvodina is chernozem (60% of total area), and it is under heavy anthropogenic pressure. Changes in soil organic matter amount resulting from switching from natural to urban ecosystems on Vojvodina's chernozem were not thoroughly researched in the past, which gave us unique insight in soil organic matter losses under human activity, namely urbanisation. The research has been carried out during July 2016 at Nature reserve Čarnok (as a control) and urban settlements Zmajevo, Vrbas and Kula, which are located 12 km from each other and Čarnok. Urban locations were lawns, chosen according to information from the owners (no known ploughing, no addition of sandy or clay material during last 70 years, no grass sowing and only direct human activity is trimming of grass). The results showed significant reduction of humus content in urban ecosystems: Čarnok (control, natural reserve) humus 5,33%, organic C 3,488%; Zmajevo humus 2,51%, organic C 1,963%; Vrbas humus 3,81%, organic C 4,216%; Kula humus 1,95%, organic C 1,517%. The differences in organic carbon also showed basically the same trend with notable exception of Vrbas. These differences in soil organic matter content is generally based on grass trimming practices. In Zmajevo, grass was trimmed monthly, with removal of biomass from the lawn, in Kula grass was trimmed twice per month with removal of biomass and in Vrbas trimming was performed once per week, with shredding of biomass and leaving it on the lawn. The conclusion was that land use change has advert impact on soil organic matter content in urban ecosystems, and that within it human practices such as trimming have significant impact on it.

  17. Correlation of soil and sediment organic matter polarity to aqueous sorption of nonionic compounds

    USGS Publications Warehouse

    Kile, D.E.; Wershaw, R. L.; Chiou, C.T.

    1999-01-01

    Polarities of the soiL/sediment organic matter (SOM) in 19 soil and 9 freshwater sediment sam pies were determined from solid-state 13C-CP/MAS NMR spectra and compared with published partition coefficients (K(oc)) of carbon tetrachloride (CT) from aqueous solution. Nondestructive analysis of whole samples by solid-state NMR permits a direct assessment of the polarity of SOM that is not possible by elemental analysis. The percent of organic carbon associated with polar functional groups was estimated from the combined fraction of carbohydrate and carboxylamide-ester carbons. A plot of the measured partition coefficients (K(oc)) of carbon tetrachloride (CT) vs. percent polar organic carbon (POC) shows distinctly different populations of soils and sediments as well as a roughly inverse trend among the soil/sediment populations. Plots of K(oc) values for CT against other structural group carbon fractions did not yield distinct populations. The results indicate that the polarity of SOM is a significant factor in accounting for differences in K(oc) between the organic matter in soils and sediments. The alternate direct correlation of the sum of aliphatic and aromatic structural carbons with K(oc) illustrates the influence of nonpolar hydrocarbon on solute partition interaction. Additional elemental analysis data of selected samples further substantiate the effect of the organic matter polarity on the partition efficiency of nonpolar solutes. The separation between soil and sediment samples based on percent POC reflects definite differences of the properties of soil and sediment organic matters that are attributable to diagenesis.Polarities of the soil/sediment organic matter (SOM) in 19 soil and 9 freshwater sediment samples were determined from solid-state 13C-CP/MAS NMR spectra and compared with published partition coefficients (Koc) of carbon tetrachloride (CT) from aqueous solution. Nondestructive analysis of whole samples by solid-state NMR permits a direct

  18. Bioavailability of organic matter in a highly disturbed Estuary: The role of detrital and algal resources

    USGS Publications Warehouse

    Sobczak, W.V.; Cloern, J.E.; Jassby, A.D.; Muller-Solger, A. B.

    2002-01-01

    The importance of algal and detrital food supplies to the planktonic food web of a highly disturbed, estuarine ecosystem was evaluated in response to declining zooplankton and fish populations. We assessed organic matter bioavailability among a diversity of habitats and hydrologic inputs over 2 years in San Francisco Estuary's Sacramento-San Joaquin River Delta. Results show that bioavailable dissolved organic carbon from external riverine sources supports a large component of ecosystem metabolism. However, bioavailable particulate organic carbon derived primarily from internal phytoplankton production is the dominant food supply to the planktonic food web. The relative importance of phytoplankton as a food source is surprising because phytoplankton production is a small component of the ecosystem's organic-matter mass balance. Our results indicate that management plans aimed at modifying the supply of organic matter to riverine, estuarine, and coastal food webs need to incorporate the potentially wide nutritional range represented by different organic matter sources.

  19. Extracorporeal membrane oxygenation for refractory septic shock in adults.

    PubMed

    Park, Taek Kyu; Yang, Jeong Hoon; Jeon, Kyeongman; Choi, Seung-Hyuk; Choi, Jin-Ho; Gwon, Hyeon-Cheol; Chung, Chi Ryang; Park, Chi Min; Cho, Yang Hyun; Sung, Kiick; Suh, Gee Young

    2015-02-01

    The role of extracorporeal membrane oxygenation (ECMO) remains controversial in adult patients with refractory septic shock. We sought to describe the clinical outcomes of adult patients supported by ECMO during septic shock refractory to conventional treatment. We analysed consecutive adult patients with refractory septic shock, assisted by an ECMO system between January 2005 and December 2013 in a single-centre registry. The primary outcome was survival to hospital discharge. A total of 32 patients (21 males) received ECMO support for refractory septic shock. Of these, 14 patients (43.8%) had undergone cardiopulmonary resuscitation (CPR) and 7 patients (21.9%) did not achieve the return of spontaneous circulation until initiation of ECMO flow. ECMO was weaned off successfully in 13 patients (40.6%) and 7 patients (21.9%) survived to hospital discharge. The survivors had lower peak lactate (4.5 vs 15.1 mmol/l, P = 0.03), lower Sepsis-related Organ Failure Assessment day 3 score (15 vs 18, P = 0.01) and higher peak troponin I (32.8 vs 3.7 ng/ml, P = 0.02) than the non-survivors. None of the patients (31.3%) in whom ECMO was initiated more than 30.5 h after onset of septic shock, survived. In multivariable-adjusted models, CPR [adjusted hazard ratio (HR), 4.61; 95% confidence interval (CI), 1.55-13.69; P = 0.006] was an independent predictor of in-hospital mortality after ECMO in patients with refractory septic shock. Higher peak troponin I > 15 ng/ml (adjusted HR, 0.34; 95% CI, 0.12-0.97; P = 0.04) was associated with a lower risk of in-hospital mortality. Survival to hospital discharge remained low in adult patients with refractory septic shock despite ECMO support. Our findings suggest that implantation of ECMO during refractory septic shock could be considered in patients with severe myocardial injury but should be avoided in patients who have received CPR. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio

  20. Isotopic constraints on the origin of meteoritic organic matter

    NASA Technical Reports Server (NTRS)

    Kerridge, J. F.

    1991-01-01

    Salient features of the isotopic distribution of H, C and N in the organic material found in carbonaceous meteorites are noted. Most organic fractions are strongly enriched in D with respect to the D/H ratio characteristic of H2 in the protosolar system; substantial variations in C-13/C-12 ratio are found among different molecular species, with oxidised species tending to be C-13 enriched relative to reduced species; some homologous series reveal systematic decrease in C-13/C-12 with increasing C number; considerable variation in N-15/N-14 ratio is observed within organic matter, though no systematic pattern to its distribution has yet emerged; no interelement correlations have been observed between isotope enrichments for the different biogenic elements. The isotopic complexity echoes the molecular diversity observed in meteoritic organic matter and suggests that the organic matter was formed by multiple processes and/or from multiple sources. However, existence of a few systematic patterns points towards survival of isotopic signatures characteristic of one or more specific processes. The widespread D enrichment implies either survival of many species of interstellar molecule or synthesis from a reservoir containing a significant interstellar component. Several of the questions raised above can be addressed by more detailed determination of the distribution of the H, C and N isotopes among different well-characterized molecular fractions. Thus, the present study is aimed at discovering whether the different amino acids have comparable D enrichments, which would imply local synthesis from a D-enriched reservoir, or very viable D enrichments, which would imply survival of some interstellar amino acids. The same approach is also being applied to polycyclic aromatic hydrocarbons. Because the analytical technique employed (secondary ion mass spectrometry) can acquire data for all three isotopic systems from each molecular fraction, any presently obscured interelement

  1. The removal characteristics of natural organic matter in the recycling of drinking water treatment sludge: Role of solubilized organics.

    PubMed

    Zhou, Zhiwei; Yang, Yanling; Li, Xing; Ji, Siyang; Zhang, Hao; Wang, Shuai; Zeng, Qingping; Han, Xinghang

    2016-01-01

    To clarify the role of solubilized organics derived from drinking water treatment sludge (DWTS) in the elimination of natural organic matter (NOM) in the DWTS recycling process, a probe sonoreactor at a frequency of 25 kHz was used to solubilize the organics at varied specific energies. The coagulation behavior related to NOM removal in recycling the sonicated DWTS with and without solubilized organics was evaluated, and the effect on organic fractionations in coagulated water was determined. The study results could provide useful implications in designing DWTS recycling processes that avoid the enrichment of organic matter. Our results indicate that DWTS was disrupted through a low release of soluble chemical oxygen demand (SCOD) and proteins, which could deteriorate the coagulated water quality under the specific energy of 37.87-1212.1 kW h/kg TS. The optimal coagulation behavior for NOM removal was achieved by recycling the sonicated DWTS without solubilized organics at 151.5 kW h/kg TS specific energy. Recycling the sonicated DWTS could increase the enrichment potential of weakly hydrophobic acid, hydrophilic matter, and <3 kDa fractions; the enrichment risks could be reduced by discharging the solubilized organics. Fluorescent characteristic analysis indicated that when recycling the sonicated DWTS without solubilized organics, the removal of humic-like substances was limited, whereas removal of protein-like substances was enhanced, lowering the enrichment potential of protein-like substances. Copyright © 2015. Published by Elsevier B.V.

  2. Chromia refractory brick with carbon treatment

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

    Bennett, James P.; Kwong, Kyei-Sing

    The disclosure provides a refractory brick system comprising a chromia refractory brick for operation in the slagging environment of an air-cooled gasifier. The chromia refractory brick comprises a ceramically-bonded porous chromia refractory having a porosity greater than 9% and having carbon deposits residing within the pores. The brick may be further comprised of Al.sub.2O.sub.3. The air-cooled gasifier generates a liquefied slag in contact with the refractory brick and generally operates at temperatures between 1250.degree. C. and 1575.degree. C. and pressures between 300 psi to 1000 psi, with oxygen partial pressures generally between 10.sup.-4 and 10.sup.-10 atm. The refractory brick performsmore » without substantial chromium carbide or chromium metal formation in the low oxygen partial pressure environment. The inclusion of carbon without chromium carbide formation provides for significant mitigation of slag penetration and significantly reduced refractory wear.« less

  3. [Inversion of organic matter content of the north fluvo-aquic soil based on hyperspectral and multi-spectra].

    PubMed

    Wang, Yan-Cang; Gu, Xiao-He; Zhu, Jin-Shan; Long, Hui-Ling; Xu, Peng; Liao, Qin-Hong

    2014-01-01

    The present study aims to assess the feasibility of multi-spectral data in monitoring soil organic matter content. The data source comes from hyperspectral measured under laboratory condition, and simulated multi-spectral data from the hyperspectral. According to the reflectance response functions of Landsat TM and HJ-CCD (the Environment and Disaster Reduction Small Satellites, HJ), the hyperspectra were resampled for the corresponding bands of multi-spectral sensors. The correlation between hyperspectral, simulated reflectance spectra and organic matter content was calculated, and used to extract the sensitive bands of the organic matter in the north fluvo-aquic soil. The partial least square regression (PLSR) method was used to establish experiential models to estimate soil organic matter content. Both root mean squared error (RMSE) and coefficient of the determination (R2) were introduced to test the precision and stability of the modes. Results demonstrate that compared with the hyperspectral data, the best model established by simulated multi-spectral data gives a good result for organic matter content, with R2=0.586, and RMSE=0.280. Therefore, using multi-spectral data to predict tide soil organic matter content is feasible.

  4. The role of clay minerals in the preservation of organic matter in sediments of Qinghai Lake, NW China

    USGS Publications Warehouse

    Yu, Bingsong; Dong, Hailiang; Jiang, Hongchen; Lv, Guo; Eberl, Dennis D.; Li, Shanying; Kim, Jinwook

    2009-01-01

    The role of saline lake sediments in preserving organic matter has long been recognized. In order to further understand the preservation mechanisms, the role of clay minerals was studied. Three sediment cores, 25, 57, and 500 cm long, were collected from Qinghai Lake, NW China, and dissected into multiple subsamples. Multiple techniques were employed, including density fractionation, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), total organic carbon (TOC) and carbon compound analyses, and surface area determination. The sediments were oxic near the water-sediment interface, but became anoxic at depth. The clay mineral content was as much as 36.8%, consisting mostly of illite, chlorite, and halloysite. The TEM observations revealed that organic matter occurred primarily as organic matter-clay mineral aggregates. The TOC and clay mineral abundances are greatest in the mid-density fraction, with a positive correlation between the TOC and mineral surface area. The TOC of the bulk sediments ranges from 1 to 3% with the non-hydrocarbon fraction being predominant, followed by bitumen, saturated hydrocarbon, aromatic hydrocarbons, and chloroform-soluble bitumen. The bimodal distribution of carbon compounds of the saturated hydrocarbon fraction suggests that organic matter in the sediments was derived from two sources: terrestrial plants and microorganisms/algae. Depthrelated systematic changes in the distribution patterns of the carbon compounds suggest that the oxidizing conditions and microbial abundance near the water-sediment interface promote degradation of labile organic matter, probably in adsorbed form. The reducing conditions and small microbial biomass deeper in the sediments favor preservation of organic matter, because of the less labile nature of organic matter, probably occurring within clay mineral-organic matter aggregates that are inaccessible to microorganisms. These results have important implications for our

  5. Glaciers as a source of ancient and labile organic matter to the marine environment.

    Treesearch

    Eran Hood; Jason Fellman; Robert G.M. Spencer; Peter J. Hernes; Rick Edwards; David D' Amore; Durelle Scott

    2009-01-01

    Riverine organic matter supports of the order of one-fifth of estuarine metabolism. Coastal ecosystems are therefore sensitive to alteration of both the quantity and lability of terrigenous dissolved organic matter (DOM) delivered by rivers. Here we characterize streamwater DOM from 11 coastal watersheds on the Gulf of Alaska that vary widely in glacier coverage. In...

  6. Hypoxia causes preservation of labile organic matter and changes seafloor microbial community composition (Black Sea).

    PubMed

    Jessen, Gerdhard L; Lichtschlag, Anna; Ramette, Alban; Pantoja, Silvio; Rossel, Pamela E; Schubert, Carsten J; Struck, Ulrich; Boetius, Antje

    2017-02-01

    Bottom-water oxygen supply is a key factor governing the biogeochemistry and community composition of marine sediments. Whether it also determines carbon burial rates remains controversial. We investigated the effect of varying oxygen concentrations (170 to 0 μM O 2 ) on microbial remineralization of organic matter in seafloor sediments and on community diversity of the northwestern Crimean shelf break. This study shows that 50% more organic matter is preserved in surface sediments exposed to hypoxia compared to oxic bottom waters. Hypoxic conditions inhibit bioturbation and decreased remineralization rates even within short periods of a few days. These conditions led to the accumulation of threefold more phytodetritus pigments within 40 years compared to the oxic zone. Bacterial community structure also differed between oxic, hypoxic, and anoxic zones. Functional groups relevant in the degradation of particulate organic matter, such as Flavobacteriia , Gammaproteobacteria , and Deltaproteobacteria , changed with decreasing oxygenation, and the microbial community of the hypoxic zone took longer to degrade similar amounts of deposited reactive matter. We conclude that hypoxic bottom-water conditions-even on short time scales-substantially increase the preservation potential of organic matter because of the negative effects on benthic fauna and particle mixing and by favoring anaerobic processes, including sulfurization of matter.

  7. Hypoxia causes preservation of labile organic matter and changes seafloor microbial community composition (Black Sea)

    PubMed Central

    Jessen, Gerdhard L.; Lichtschlag, Anna; Ramette, Alban; Pantoja, Silvio; Rossel, Pamela E.; Schubert, Carsten J.; Struck, Ulrich; Boetius, Antje

    2017-01-01

    Bottom-water oxygen supply is a key factor governing the biogeochemistry and community composition of marine sediments. Whether it also determines carbon burial rates remains controversial. We investigated the effect of varying oxygen concentrations (170 to 0 μM O2) on microbial remineralization of organic matter in seafloor sediments and on community diversity of the northwestern Crimean shelf break. This study shows that 50% more organic matter is preserved in surface sediments exposed to hypoxia compared to oxic bottom waters. Hypoxic conditions inhibit bioturbation and decreased remineralization rates even within short periods of a few days. These conditions led to the accumulation of threefold more phytodetritus pigments within 40 years compared to the oxic zone. Bacterial community structure also differed between oxic, hypoxic, and anoxic zones. Functional groups relevant in the degradation of particulate organic matter, such as Flavobacteriia, Gammaproteobacteria, and Deltaproteobacteria, changed with decreasing oxygenation, and the microbial community of the hypoxic zone took longer to degrade similar amounts of deposited reactive matter. We conclude that hypoxic bottom-water conditions—even on short time scales—substantially increase the preservation potential of organic matter because of the negative effects on benthic fauna and particle mixing and by favoring anaerobic processes, including sulfurization of matter. PMID:28246637

  8. Interaction between inorganic nutrients and organic matter in controlling coral reef communities in Glovers Reef Belize.

    PubMed

    McClanahan, T R; Steneck, R S; Pietri, D; Cokos, B; Jones, S

    2005-05-01

    We studied the responses of algae, corals, and small fish to elevated inorganic fertilizer, organic matter, and their combination over a 49-day summer period in cages that simulated the coral reef in the remote Glovers reef atoll, Belize. The addition of organic matter reduced while fertilization had no effect on the numbers of herbivorous damsel and parrotfishes. All measures of algal biomass were influenced by fertilization. The combined inorganic and organic enrichment produced the highest algal biomass, which is most likely due to the combined effect of higher nutrients and lower herbivory. The cover of turf and total algae were influenced by all treatments and their interactions and most strongly and positively influenced by fertilization followed by organic matter and the combination of organic matter and inorganic fertilizer. The inorganic and combined treatments were both dominated by two turf algae, Enteromorpha prolifera and Digenia simplex, while the nonfertilized treatments were dominated by brown frondose algae Lobophora variegata, Padina sanctae, and Dictyota cervicornis. The organic matter treatment had greater cover of P. sanctae and D. cervicornis than the untreated control, which was dominated by Lobophora variegata, also the dominant algae on the nearby patch reefs. Crustose corallines grew slowly ( approximately 2.5 mm/49 days) and were not influenced by the treatments when grown on vertical surfaces but decreased on horizontal coral plates in the combined organic matter and fertilization treatment. No mortality occurred for the two coral species that were added to the cages. Porites furcata darkened in the fertilized cages while there was a mix of paling and darkening for a small amount of the coral tissue of Diploria labyrinthiformes. Inorganic fertilization stimulates small filamentous turf algae and Symbiodinium living in coral but inhibits brown frondose algae. Organic matter inhibits small herbivorous fish, L. variegata, and encrusting

  9. Influence of land use and land cover on the spatial variability of dissolved organic matter in multiple aquatic environments.

    PubMed

    Singh, Shatrughan; Dash, Padmanava; Silwal, Saurav; Feng, Gary; Adeli, Ardeshir; Moorhead, Robert J

    2017-06-01

    phosphorous (TDP) and ammonium nitrogen (NH 4 -N) in coastal waters potentially due to photodegradation of refractory DOM derived from the sediment-bound organic matter in the coastal wetlands. This study highlights the relationships between the DOM compositions in the water and the land use and land cover in the watershed. The spatial variability of DOM in three different types of aquatic environments enhances the understanding of the role of land use and land cover in carbon cycling through export of organic matter to the aquatic ecosystems..

  10. The effect of flood events on the partitioning of labile and refractory carbon in the Missouri-Mississippi River system

    NASA Astrophysics Data System (ADS)

    Roe, K. M.; Rosenheim, B. E.; Kolker, A.; Allison, M. A.; Nittrouer, J. A.; Duncan, D. D.; Nyman, J. A.; Butcher, K. A.; Adamic, J. F.

    2009-12-01

    The Missouri-Mississippi River system (MMRS) transports over 40% (4.0 x 109 kg) of the United States's annual input of total organic carbon (OC) from land to the marine environment, yet it is challenging to assess the MMRS’s exact role in the global carbon cycle because of the system’s complexity and temporal variability (i.e. high discharge events and low flow regimes). Determining the relative proportion of labile OC to refractory OC entrained in the MMRS during high and mean flow conditions would lend to the understanding of the MMRS’s role in the flux of carbon between the biospheric and atmospheric reservoirs, which is central to determining the role of anthropogenic CO2 in the global carbon cycle and in climate change. In this study, we investigate the relative proportion of labile OC to refractory OC in the lower MMRS during high and near-mean flow conditions in the springs of 2008 and 2009, respectively. The 2008 spring flood discharged 105 km3 of water, the maximum amount of water ever allowed out of the main channel, at a maximum rate of 4.3 x 104 m3s-1. Events of this scale have occurred only nine times in the past 80 years. Additionally, during the spring 2008 flood, bedload sand and large particulate OC transport rates were observed to increase exponentially. The following spring, high discharge rates returned to near-mean values with a peak discharge of 3.6 x 103 m3s-1. Using radiocarbon age and the thermal stability of organic matter (OM) as a proxy for lability, we evaluate the spectra of ages of particulate OM transported in the lower MMRS during these two flow regimes using a programmed-temperature pyrolysis/combustion system (PTP/CS) coupled with 14C determination. The PTP/CS utilizes the differences in thermal stability of acid insoluble particulate organic matter (AIPOM) to separate different components from the bulk. Employing PTP/CS on bulk AIPOM can complement experiments measuring small proportions of total OM such as compound

  11. Characterization and origin of polar dissolved organic matter from the Great Salt Lake

    USGS Publications Warehouse

    Leenheer, J.A.; Noyes, T.I.; Rostad, C.E.; Davisson, M.L.

    2004-01-01

    Polar dissolved organic matter (DOM) was isolated from a surface-water sample from the Great Salt Lake by separating it from colloidal organic matter by membrane dialysis, from less-polar DOM fractions by resin sorbents, and from inorganic salts by a combination of sodium cation exchange followed by precipitation of sodium salts by acetic acid during evaporative concentration. Polar DOM was the most abundant DOM fraction, accounting for 56% of the isolated DOM. Colloidal organic matter was 14C-age dated to be about 100% modern carbon and all of the DOM fractions were 14C-age dated to be between 94 and 95% modern carbon. Average structural models of each DOM fraction were derived that incorporated quantitative elemental and infrared, 13C-NMR, and electrospray/mass spectrometric data. The polar DOM model consisted of open-chain N-acetyl hydroxy carboxylic acids likely derived from N-acetyl heteropolysaccharides that constituted the colloidal organic matter. The less polar DOM fraction models consisted of aliphatic alicyclic ring structures substituted with carboxyl, hydroxyl, ether, ester, and methyl groups. These ring structures had characteristics similar to terpenoid precursors. All DOM fractions in the Great Salt Lake are derived from algae and bacteria that dominate DOM inputs in this lake.

  12. Classes of organic molecules targeted by a methanogenic microbial consortium grown on sedimentary rocks of various maturities

    PubMed Central

    Meslé, Margaux; Dromart, Gilles; Haeseler, Frank; Oger, Philippe M.

    2015-01-01

    Organic-rich shales are populated by methanogenic consortia that are able to degrade the fossilized organic matter into methane gas. To identify the organic fraction effectively degraded, we have sequentially depleted two types of organic-rich sedimentary rocks, shale, and coal, at two different maturities, by successive solvent extractions to remove the most soluble fractions (maltenes and asphaltenes) and isolate kerogen. We show the ability of the consortia to produce methane from all rock samples, including those containing the most refractory organic matter, i.e., the kerogen. Shales yielded higher methane production than lignite and coal. Mature rocks yielded more methane than immature rocks. Surprisingly, the efficiency of the consortia was not influenced by the removal of the easily biodegradable fractions contained in the maltenes and asphaltenes. This suggests that one of the limitations of organic matter degradation in situ may be the accessibility to the carbon and energy source. Indeed, bitumen has a colloidal structure that may prevent the microbial consortia from reaching the asphaltenes in the bulk rock. Solvent extractions might favor the access to asphaltenes and kerogen by modifying the spatial organization of the molecules in the rock matrix. PMID:26136731

  13. Molecular characterization of effluent organic matter in secondary effluent and reclaimed water: Comparison to natural organic matter in source water.

    PubMed

    Wang, Xin; Wang, Juan; Li, Kuixiao; Zhang, Haifeng; Yang, Min

    2018-01-01

    Municipal wastewater reclamation is becoming of increasing importance in the world to solve the problem of water scarcity. A better understanding of the molecular composition of effluent organic matter (EfOM) in the treated effluents of municipal wastewater treatment plants (WWTPs) is crucial for ensuring the safety of water reuse. In this study, the molecular composition of EfOM in the secondary effluent of a WWTP in Beijing and the reclaimed water further treated with a coagulation-sedimentation-ozonation process were characterized using a non-target Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) method and compared to that of natural organic matter (NOM) in the local source water from a reservoir. It was found that the molecular composition of EfOM in the secondary effluent and reclaimed water was dominated by CHOS formulas, while NOM in the source water was dominated by CHO formulas. The CHO formulas of the three samples had similar origins. Anthropogenic surfactants were responsible for the CHOS formulas in EfOM of the secondary effluent and were not well removed by the coagulation-sedimentation-ozonation treatment process adopted. Copyright © 2017. Published by Elsevier B.V.

  14. Utilization of organic matter by invertebrates along an estuarine gradient in an intermittently open estuary

    NASA Astrophysics Data System (ADS)

    Lautenschlager, Agnes D.; Matthews, Ty G.; Quinn, Gerry P.

    2014-08-01

    In intermittently open estuaries, the sources of organic matter sustaining benthic invertebrates are likely to vary seasonally, particularly between periods of connection and disconnection with the ocean and higher and lower freshwater flows. This study investigated the contribution of allochthonous and autochthonous primary production to the diet of representative invertebrate species using stable isotope analysis (SIA) during the austral summer and winter (2008, 2009) in an intermittently open estuary on the south-eastern coast of Australia. As the study was conducted towards the end of a prolonged period of drought, a reduced influence of freshwater/terrestrial organic matter was expected. Sampling was conducted along an estuarine gradient, including upper, middle and lower reaches and showed that the majority of assimilated organic matter was derived from autochthonous estuarine food sources. Additionally, there was an input of allochthonous organic matter, which varied along the length of the estuary, indicated by distinct longitudinal trends in carbon and nitrogen stable isotope signatures along the estuarine gradient. Marine seaweed contributed to invertebrate diets in the lower reaches of the estuary, while freshwater/terrestrial organic matter had increased influence in the upper reaches. Suspension-feeding invertebrates derived large parts of their diet from freshwater/terrestrial material, despite flows being greatly reduced in comparison with non-drought years.

  15. Dispersion of kaolinite by dissolved organic matter from Douglas-fir roots

    Treesearch

    Philip B. Durgin; Jesse G. Chaney

    1984-01-01

    The organic constituents of water extracts from Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) roots that cause kaolinite dispersion were investigated. The dissolved organic matter was fractionated according to molecular size and chemical characteristics into acids, neutrals, and bases of the hydrophilic and hydrophobic groups.

  16. A demonstration of an affinity between pyrite and organic matter in a hydrothermal setting

    PubMed Central

    2011-01-01

    One of the key-principles of the iron-sulphur world theory is to bring organic molecules close enough to interact with each other, using the surface of pyrite as a substrate in a hydrothermal setting. The present paper explores the relationship of pyrite and organic matter in a hydrothermal setting from the geological record; in hydrothermal calcite veins from Carboniferous limestones in central Ireland. Here, the organic matter is accumulated as coatings around, and through, pyrite grains. Most of the pyrite grains are euhedral-subhedral crystals, ranging in size from ca 0.1-0.5 mm in diameter, and they are scattered throughout the matrix of the vein calcite. The organic matter was deposited from a hydrothermal fluid at a temperature of at least 200°C, and gives a Raman signature of disordered carbon. This study points to an example from a hydrothermal setting in the geological record, demonstrating that pyrite can have a high potential for the concentration and accumulation of organic materials. PMID:21299877

  17. Organic Matter Application Can Reduce Copper Toxicity in Tomato Plants

    ERIC Educational Resources Information Center

    Campbell, Brian

    2010-01-01

    Copper fungicides and bactericides are often used in tomato cultivation and can cause toxic Cu levels in soils. In order to combat this, organic matter can be applied to induce chelation reactions and form a soluble complex by which much of the Cu can leach out of the soil profile or be taken up safely by plants. Organic acids such as citric,…

  18. In Situ Mapping of the Organic Matter in Carbonaceous Chondrites and Mineral Relationships

    NASA Technical Reports Server (NTRS)

    Clemett, Simon J.; Messenger, S.; Thomas-Keprta, K. L.; Ross, D. K.

    2012-01-01

    Carbonaceous chondrite organic matter represents a fossil record of reactions that occurred in a range of physically, spatially and temporally distinct environments, from the interstellar medium to asteroid parent bodies. While bulk chemical analysis has provided a detailed view of the nature and diversity of this organic matter, almost nothing is known about its spatial distribution and mineralogical relationships. Such information is nevertheless critical to deciphering its formation processes and evolutionary history.

  19. Linking geochemical processes in mud volcanoes with arsenic mobilization driven by organic matter.

    PubMed

    Liu, Chia-Chuan; Kar, Sandeep; Jean, Jiin-Shuh; Wang, Chung-Ho; Lee, Yao-Chang; Sracek, Ondra; Li, Zhaohui; Bundschuh, Jochen; Yang, Huai-Jen; Chen, Chien-Yen

    2013-11-15

    The present study deals with geochemical characterization of mud fluids and sediments collected from Kunshuiping (KSP), Liyushan (LYS), Wushanting (WST), Sinyangnyuhu (SYNH), Hsiaokunshui (HKS) and Yenshuikeng (YSK) mud volcanoes in southwestern Taiwan. Chemical constituents (cations, anions, trace elements, organic carbon, humic acid, and stable isotopes) in both fluids and mud were analyzed to investigate the geochemical processes and spatial variability among the mud volcanoes under consideration. Analytical results suggested that the anoxic mud volcanic fluids are highly saline, implying connate water as the probable source. The isotopic signature indicated that δ(18)O-rich fluids may be associated with silicate and carbonate mineral released through water-rock interaction, along with dehydration of clay minerals. Considerable amounts of arsenic in mud irrespective of fluid composition suggested possible release through biogeochemical processes in the subsurface environment. Sequential extraction of As from the mud indicated that As was mostly present in organic and sulphidic phases, and adsorbed on amorphous Mn oxyhydroxides. Volcanic mud and fluids are rich in organic matter (in terms of organic carbon), and the presence of humic acid in mud has implications for the binding of arsenic. Functional groups of humic acid also showed variable sources of organic matter among the mud volcanoes being examined. Because arsenate concentration in the mud fluids was found to be independent from geochemical factors, it was considered that organic matter may induce arsenic mobilization through an adsorption/desorption mechanism with humic substances under reducing conditions. Organic matter therefore plays a significant role in the mobility of arsenic in mud volcanoes. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Flood Pulse Influence on Export of Terrestrial Organic Matter

    NASA Astrophysics Data System (ADS)

    Dalzell, B. J.; Harbor, J. M.; Filley, T. R.

    2004-12-01

    While much attention has been placed on characterizing Terrestrial Organic Matter (TOM) export from large rivers, recent research has shown that in-stream processing of TOM in smaller streams and rivers over shorter time scales can be an important upland component of regional carbon budgets not detected at the outlets of large rivers. With predictions of climate change accompanied by more intense rainfall patterns in some areas, it is important to understand the linkage between flood events and watershed export of TOM. To this end, we have collected water samples from Big Pine Creek watershed, an 850km2 watershed located in west central Indiana. Organic carbon in dissolved, colloidal, and particulate size fractions has been described with molecular and stable carbon isotope techniques to track source, quantity, and compositional changes of TOM over changing flow conditions. Results from these samples show that flood conditions export dramatically more TOM; not only from increases in discharge, but also from increases in concentration of terrestrial organic carbon to all size fractions. While molecular biomarkers show increases in terrestrial organic matter, bulk stable carbon isotope values show that the sources of TOM do not remain constant. Rather, relative contributions from C4 plants (corn in this study area) increase during flood conditions by up to 40 percent. Finally, increases in rainfall intensity are likely to disproportionately increase organic carbon export from terrestrial systems, especially from smaller watersheds where short duration and high intensity flow events dominate annual discharge.

  1. Thallium and Silver binding to dissolved organic matter

    NASA Astrophysics Data System (ADS)

    Benedetti, M. F.; Martin, L.; Simonucci, C.; Viollier, E.

    2017-12-01

    Silver (Ag) and thallium (Tl) are potential contaminants at the vicinity of mining sites and are harmful pollutants. Silver can be found in mine but also as released by the dissolution of Silver nanoparticles, a major new emerging contaminant. Tl is both lithophilic and calcophilic elements and found in sulphur ores (associated with lead, zinc, antimony…) or in rocks containing K-feldspar. Speciation of Ag and Tl is poorly known mainly due to their low concentrations in aquatic environments. Review of Ag and Tl geochemistry clearly shows a lack of quantitative information about interactions with natural organic matter. Organic ligands could play an important role in Ag or Tl bioavailability, chemical reactivity (adsorption or photo oxidation inhibition or catalysis) and hence geochemical transfers. Based on equilibrium between two solutions that are separated by a selectively permeable membrane, the so-called "Donnan membrane technique" (DMT) provides a measure of free ion concentrations. Analytes measurements are performed by HR-ICP-MS Element 2 (Thermo Scientific). Experimental setup allows the Donnan equilibrium to be reached after 100 and 120 hours for Tl. Experiments performed with purified natural organic matter allow calculating complexation constants in multiple pH conditions. With this work, we contribute new data and interpretations to an active debate on Ag and Tl geochemical modeling. In conclusion, this work brings a new view on risk assessment for mining activities.

  2. Composition of whole and water extractable organic matter of cattle manure affected by management practices

    USDA-ARS?s Scientific Manuscript database

    Organic matter (OM) is a major component of animal manure. In this chapter, we present two case studies on the multiple spectral features of whole and water extractable organic matter (WEOM) of cattle (beef and dairy) manure affected by differing management practices. Using wet chemistry and Fourie...

  3. Chemical characterization of detrital sugar chains with peptides in oceanic surface particulate organic matter

    NASA Astrophysics Data System (ADS)

    Tsukasaki, A.; Nishida, T.; Tanoue, E.

    2016-02-01

    For better understanding of the dynamics of organic matter in the ocean interior, particulate organic matter (POM) in oceanic surface water is a key material as a starting material in food chain and biological carbon pump, and the source of dissolved organic matter. POM consists of a mixture of non-living POM (detritus) and small amount of living POM (organisms). Particulate combined amino acids (PCAAs) are one of the major components of POM and the most important source of nitrogen and carbon for heterotrophic organisms in marine environments. In our previous studies of molecular-level characterization of PCAAs using electrophoretic separation (SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis) with specific detection of protein/peptide and sugar chains, we reported that most of PCAAs existed as small-sized peptide chains with carbohydrate-rich remnants. Although carbohydrates are one of the major carbon components of POM, the details of molecular-level structures including sugar chains are unknown. In this study, we applied electrophoretic separation for sugar chains (FACE: fluorophore-assisted carbohydrate electrophoresis) to the POM samples collected from the surface water of the Pacific Ocean. The results showed that sugar chains with various degree of polymerization were detected in POM. The possible roles of such sugar chains in marine biogeochemical cycle of organic matter are discussed in the presentation.

  4. Sea cucumbers reduce chromophoric dissolved organic matter in aquaculture tanks

    PubMed Central

    Sadeghi-Nassaj, Seyed Mohammad; Catalá, Teresa S.; Álvarez, Pedro A.

    2018-01-01

    Background Mono-specific aquaculture effluents contain high concentrations of nutrients and organic matter, which affect negatively the water quality of the recipient ecosystems. A fundamental feature of water quality is its transparency. The fraction of dissolved organic matter that absorbs light is named chromophoric dissolved organic matter (CDOM). A sustainable alternative to mono-specific aquaculture is the multitrophic aquaculture that includes species trophically complementary named “extractive” species that uptake the waste byproducts. Sea cucumbers are recognized as efficient extractive species due to the consumption of particulate organic matter (POM). However, the effects of sea cucumbers on CDOM are still unknown. Methods During more than one year, we monitored CDOM in two big-volume tanks with different trophic structure. One of the tanks (−holothurian) only contained around 810 individuals of Anemonia sulcata, whereas the other tank (+holothurian) also included 90 individuals of Holothuria tubulosa and Holothuria forskali. We routinely analyzed CDOM absorption spectra and determined quantitative (absorption coefficients at 325 nm) and qualitative (spectral slopes) optical parameters in the inlet waters, within the tanks, and in their corresponding effluents. To confirm the time-series results, we also performed three experiments. Each experiment consisted of two treatments: +holothurians (+H) and –holothurians (−H). We set up three +H tanks with 80 individuals of A. sulcata and 10 individuals of H. tubulosa in each tank and four –H tanks that contained only 80 individuals of A. sulcata. Results In the time-series, absorption coefficients at 325 nm (a325) and spectral slopes from 275 to 295 nm (S275−295) were significantly lower in the effluent of the +holothurian tank (average: 0.33 m−1 and 16 µm−1, respectively) than in the effluent of the −holothurian tank (average: 0.69 m−1 and 34 µm−1, respectively), the former being

  5. Effects of Natural Organic Matter on Stability, Transport and Deposition of Engineered Nano-particles in Porous Media

    EPA Science Inventory

    The interaction of nano-particles and organic substances, like natural organic matter, could have significant influence on the fate, transport and bioavailability of toxic substances. Natural organic matter (NOM) is a mixture of chemically complex polyelectrolytes with varying m...

  6. Extending the analytical window for water-soluble organic matter in sediments by aqueous Soxhlet extraction

    NASA Astrophysics Data System (ADS)

    Schmidt, Frauke; Koch, Boris P.; Witt, Matthias; Hinrichs, Kai-Uwe

    2014-09-01

    Dissolved organic matter (DOM) in marine sediments is a complex mixture of thousands of individual constituents that participate in biogeochemical reactions and serve as substrates for benthic microbes. Knowledge of the molecular composition of DOM is a prerequisite for a comprehensive understanding of the biogeochemical processes in sediments. In this study, interstitial water DOM was extracted with Rhizon samplers from a sediment core from the Black Sea and compared to the corresponding water-extractable organic matter fraction (<0.4 μm) obtained by Soxhlet extraction, which mobilizes labile particulate organic matter and DOM. After solid phase extraction (SPE) of DOM, samples were analyzed for the molecular composition by Fourier Transform Ion-Cyclotron Resonance Mass Spectrometry (FT-ICR MS) with electrospray ionization in negative ion mode. The average SPE extraction yield of the dissolved organic carbon (DOC) in interstitial water was 63%, whereas less than 30% of the DOC in Soxhlet-extracted organic matter was recovered. Nevertheless, Soxhlet extraction yielded up to 4.35% of the total sedimentary organic carbon, which is more than 30-times the organic carbon content of the interstitial water. While interstitial water DOM consisted primarily of carbon-, hydrogen- and oxygen-bearing compounds, Soxhlet extracts yielded more complex FT-ICR mass spectra with more peaks and higher abundances of nitrogen- and sulfur-bearing compounds. The molecular composition of both sample types was affected by the geochemical conditions in the sediment; elevated concentrations of HS- promoted the early diagenetic sulfurization of organic matter. The Soxhlet extracts from shallow sediment contained specific three- and four-nitrogen-bearing molecular formulas that were also detected in bacterial cell extracts and presumably represent proteinaceous molecules. These compounds decreased with increasing sediment depth while one- and two-nitrogen-bearing molecules increased

  7. Characteristics of DO, organic matter, and ammonium profile for practical-scale DHS reactor under various organic load and temperature conditions.

    PubMed

    Nomoto, Naoki; Ali, Muntjeer; Jayaswal, Komal; Iguchi, Akinori; Hatamoto, Masashi; Okubo, Tsutomu; Takahashi, Masanobu; Kubota, Kengo; Tagawa, Tadashi; Uemura, Shigeki; Yamaguchi, Takashi; Harada, Hideki

    2018-04-01

    Profile analysis of the down-flow hanging sponge (DHS) reactor was conducted under various temperature and organic load conditions to understand the organic removal and nitrification process for sewage treatment. Under high organic load conditions (3.21-7.89 kg-COD m -3  day -1 ), dissolved oxygen (DO) on the upper layer of the reactor was affected by organic matter concentration and water temperature, and sometimes reaches around zero. Almost half of the COD Cr was removed by the first layer, which could be attributed to the adsorption of organic matter on sponge media. After the first layer, organic removal proceeded along the first-order reaction equation from the second to the fourth layers. The ammoniacal nitrogen removal ratio decreased under high organic matter concentration (above 100 mg L -1 ) and low DO (less than 1 mg L -1 ) condition. Ammoniacal nitrogen removal proceeded via a zero-order reaction equation along the reactor height. In addition, the profile results of DO, COD Cr , and NH 3 -N were different in the horizontal direction. Thus, it is thought the concentration of these items and microbial activities were not in a uniform state even in the same sponge layer of the DHS reactor.

  8. Enzymatic regulation of organic matter metabolism in Siberia's Kolyma River Watershed

    NASA Astrophysics Data System (ADS)

    Mann, P. J.; Sobczak, W.; Vonk, J. E.; Davydova, A.; Schade, J.; Bulygina, E.; Davydov, S.; Zimov, N.; Holmes, R. M.

    2012-04-01

    Arctic soils contain vast amounts of ancient organic carbon stored in permafrost that can be unlocked and remobilised via permafrost thaw and bacterial degradation. The mechanisms regulating the release and fate of this carbon are important to understand if we wish to predict future changes in the global carbon cycle. Microbial communities release enzymes into the environment (ectoenzymes) as a means of degrading organic matter and to acquire carbon, nitrogen and phosphorus for assimilation. We measured potential activities of a suite of ectoenzymes within surface waters collected from a range of streams and rivers throughout the Kolyma River basin, Siberia. Ectoenzyme activities were additionally measured in Kolyma river waters collected at three distinct periods of the hydrograph (under-ice, freshet and summer conditions). Seven enzymes were studied allowing bacterial requirements for a wide range of compounds including lignin, carbohydrates, proteins and cellulose to be assessed. Concurrent measurements of DOC lability were conducted using biological oxygen demand assays conducted over 5 days (BOD). Phenol oxidase activity was found to strongly correlate to BOD (r2=0.68) and stream CO2 concentration (r2=0.76) across all of the study sites, suggesting the rate of phenolic degradation may be a controlling factor in organic carbon metabolism. The activity rate in ectoenzymes that catalyze phosphate, lignin and carbon substrates varied significantly within the Kolyma river over the hydrograph, suggesting that seasonal changes in organic matter composition may also shift the limiting resource for bacterial degradation. Extremely high activity rates in ectoenzymes that catalyze lignin, chitin, cellulose and proteins were measured in waters draining permafrost ice complexes. It is apparent that organic carbon is continually processed throughout the stream network, and that its ultimate fate is linked to organic matter composition. We demonstrate that organic carbon

  9. Thermal alterations of organic matter in coal wastes from Upper Silesia, Poland

    NASA Astrophysics Data System (ADS)

    Misz-Kennan, Magdalena

    2010-01-01

    Self-heating and self-combustion are currently taking place in some coal waste dumps in the Upper Silesian Coal Basin, Poland, e.g. the dumps at Rymer Cones, Starzykowiec, and the Marcel Coal Mine, all in the Rybnik area. These dumps are of similar age and self-heating and combustion have been occurring in all three for many years. The tools of organic petrography (maceral composition, rank, etc.), gas chromatography-mass spectrometry, and proximate and ultimate analysis are used to investigate the wastes. Organic matter occurs in quantities up to 85 vol.%, typically a few to several vol.%, in the wastes. All three maceral groups (vitrinite, liptinite, and inertinite) are present as unaltered and variously-altered constituents associated with newly-formed petrographic components (bitumen expulsions, pyrolytic carbon). The predominant maceral group is vitrinite with alterations reflected in the presence of irregular cracks, oxidation rims and, rarely, devolatilisation pores. In altered wastes, paler grey-vitrinite and/or coke dominates. The lack of plasticity, the presence of paler-coloured particles, isotropic massive coke, dispersed coked organic matter, and expulsions of bitumens all indicate that heating was slow and extended over a long time. Macerals belonging to other groups are present in unaltered form or with colours paler than the colours of the parent macerals. Based on the relative contents of organic compounds, the most important groups of these identified in the wastes are n-alkanes, acyclic isoprenoids, hopanes, polycyclic aromatic hydrocarbons (PAHs) and their derivatives, phenol and its derivatives. These compounds occur in all wastes except those most highly altered where they were probably destroyed by high temperatures. These compounds were generated mainly from liptinite-group macerals. Driven by evaporation and leaching, they migrated within and out of the dump. Their presence in some wastes in which microscopically visible

  10. Effect of organic matter amendment, arsenic amendment and water management regime on rice grain arsenic species.

    PubMed

    Norton, Gareth J; Adomako, Eureka E; Deacon, Claire M; Carey, Anne-Marie; Price, Adam H; Meharg, Andrew A

    2013-06-01

    Arsenic accumulation in rice grain has been identified as a major problem in some regions of Asia. A study was conducted to investigate the effect of increased organic matter in the soil on the release of arsenic into soil pore water and accumulation of arsenic species within rice grain. It was observed that high concentrations of soil arsenic and organic matter caused a reduction in plant growth and delayed flowering time. Total grain arsenic accumulation was higher in the plants grown in high soil arsenic in combination with high organic matter, with an increase in the percentage of organic arsenic species observed. The results indicate that the application of organic matter should be done with caution in paddy soils which have high soil arsenic, as this may lead to an increase in accumulation of arsenic within rice grains. Results also confirm that flooding conditions substantially increase grain arsenic. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Fungal community composition in soils subjected to long-term chemical fertilization is most influenced by the type of organic matter.

    PubMed

    Sun, Ruibo; Dsouza, Melissa; Gilbert, Jack A; Guo, Xisheng; Wang, Daozhong; Guo, Zhibin; Ni, Yingying; Chu, Haiyan

    2016-12-01

    Organic matter application is a widely used practice to increase soil carbon content and maintain soil fertility. However, little is known about the effect of different types of organic matter, or the input of exogenous species from these materials, on soil fungal communities. In this study, fungal community composition was characterized from soils amended with three types of organic matter over a 30-year fertilization experiment. Chemical fertilization significantly changed soil fungal community composition and structure, which was exacerbated by the addition of organic matter, with the direction of change influenced by the type of organic matter used. The addition of organic matter significantly increased soil fungal richness, with the greatest richness achieved in soils amended with pig manure. Importantly, following addition of cow and pig manure, fungal taxa associated with these materials could be found in the soil, suggesting that these exogenous species can augment soil fungal composition. Moreover, the addition of organic matter decreased the relative abundance of potential pathogenic fungi. Overall, these results indicate that organic matter addition influences the composition and structure of soil fungal communities in predictable ways. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Investigation of water-soluble organic matter extracted from shales during leaching experiments

    NASA Astrophysics Data System (ADS)

    Zhu, Yaling; Vieth-Hillebrand, Andrea; Wilke, Franziska D. H.; Horsfield, Brian

    2017-04-01

    The huge volumes and unknown composition of flowback and produced waters cause major public concerns about the environmental and social compatibility of hydraulic fracturing and the exploitation of gas from unconventional reservoirs. Flowback and produced waters contain not only residues of fracking additives but also chemical species that are dissolved from the shales themselves during fluid-rock interaction. Knowledge of the composition, size and structure of dissolved organic carbon (DOC) as well as the main controls on the release of DOC are a prerequisite for a better understanding of these interactions and its effects on composition of flowback and produced water. Black shales from four different geological settings and covering a maturity range Ro = 0.3-2.6% were extracted with deionized water. The DOC yields were found to decrease rapidly with increasing diagenesis and remain low throughout catagenesis. Four DOC fractions have been qualitatively and quantitatively characterized using size-exclusion chromatography. The concentrations of individual low molecular weight organic acids (LMWOA) decrease with increasing maturity of the samples except for acetate extracted from the overmature Posidonia shale, which was influenced by hydrothermal brines. The oxygen content of the shale organic matter also shows a significant influence on the release of organic acids, which is indicated by the positive trend between oxygen index (OI) and the concentrations of formate and acetate. Based on our experiments, both the properties of the organic matter source and the thermal maturation progress of the shale organic matter significantly influence the amount and quality of extracted organic compounds during the leaching experiments.

  13. Phytoplankton Do Not Produce Carbon-Rich Organic Matter in High CO2 Oceans

    NASA Astrophysics Data System (ADS)

    Kim, Ja-Myung; Lee, Kitack; Suh, Young-Sang; Han, In-Seong

    2018-05-01

    The ocean is a substantial sink for atmospheric carbon dioxide (CO2) released as a result of human activities. Over the coming decades the dissolved inorganic C concentration in the surface ocean is predicted to increase, which is expected to have a direct influence on the efficiency of C utilization (consumption and production) by phytoplankton during photosynthesis. Here we evaluated the generality of C-rich organic matter production by examining the elemental C:N ratio of organic matter produced under conditions of varying pCO2. The data used in this analysis were obtained from a series of pelagic in situ pCO2 perturbation studies that were performed in the diverse ocean regions and involved natural phytoplankton assemblages. The C:N ratio of the resulting particulate and dissolved organic matter did not differ across the range of pCO2 conditions tested. In particular, the ratio for particulate organic C and N was found to be 6.58 ± 0.05, close to the theoretical value of 6.6.

  14. Irradiation of organic matter by uranium decay in the Alum Shale, Sweden

    NASA Astrophysics Data System (ADS)

    Lewan, M. D.; Buchardt, B.

    1989-06-01

    The Alum Shale of Sweden contains black shales with anomalously high uranium concentrations in excess of 100 ppm. Syngenetic or early diagenetic origin of this uranium indicates that organic matter within these shales has been irradiated by decaying uranium for approximately 500 Ma. Radiation-induced polymerization of alkanes through a free-radical cross-linking mechanism appears to be responsible for major alterations within the irradiated organic matter. Specific radiation-induced alterations include generation of condensate-like oils at reduced yields from hydrous pyrolysis experiments, decrease in atomic H/C ratios of kerogens, decrease in bitumen/organic-carbon ratios, and a relative increase in low-molecular weight triaromatic steroid hydrocarbons. Conversely, stable carbon isotopes of kerogens, reflectance of vitrinite-like macerais, oil-generation kinetics, and isomerization of 20R to 20S αα C 29-steranes were not affected by radiation. The radiation dosage needed to cause the alterations observed in the Alum Shale has been estimated to be in excess of 10 5 Mrads with respect to organic carbon. This value is used to estimate the potential for radiation damage to thermally immature organic matter in black shales through the geological rock record. High potential for radiation damage is not likely in Cenozoic and Mesozoic black shales but becomes more likely in lower Paleozoic and Precambrian black shales.

  15. Refractory metals for ARPS AMTEC cells

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

    Svedberg, R.C.; Sievers, R.C.

    1998-07-01

    Alkali Metal Thermal-to-Electric Converter (AMTEC) cells for the Advanced Radioisotope Power Systems (ARPS) program are being developed with refractory metals and alloys as the basic structural materials. AMTEC cell efficiency increases with cell operating temperature. For space applications, long term reliability and high efficiency are essential and refractory metals were selected because of their high temperature strength, low vapor pressure, and compatibility with sodium. However, refractory metals are sensitive to oxygen, nitrogen and hydrogen contamination and refractory metal cells cannot be processed in air. Because of this sensitivity, new manufacturing and processing techniques are being developed. In addition to structuralmore » elements, development of other refractory metal components for the AMTEC cells, such as the artery and evaporator wicks, pinchoff tubes and feedthroughs are required. Changes in cell fabrication techniques and processing procedures being implemented to manufacture refractory metal cells are discussed.« less

  16. Storage and export of organic matter in a headwater stream: responses to long-term detrital manipulations

    Treesearch

    Sue L. Eggert; J. Bruce Wallace; Judy L. Meyer; Jackson R. Webster

    2012-01-01

    Riparian habitats provide organic matter inputs that influence stream biota and ecosystem processes in forested watersheds. Over a 13-yr period, we examined the effects of litter exclusion, small- and large-wood removal, and the addition of leaf species of varying detrital quality on organic matter standing crop and export of organic and inorganic particles in a high-...

  17. SPRUCE Advanced Molecular Techniques Provide a Rigorous Method for Characterizing Organic Matter Quality in Complex Systems: Supporting Data

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

    Wilson, Rachel M; Tfaily, Malak M

    These data are provided in support of the Commentary, Advanced molecular techniques provide a rigorous method for characterizing organic matter quality in complex systems, Wilson and Tfaily (2018). Measurement results demonstrate that optical characterization of peatland dissolved organic matter (DOM) may not fully capture classically identified chemical characteristics and may, therefore, not be the best measure of organic matter quality.

  18. Role of effluent organic matter in the photochemical degradation of compounds of wastewater origin.

    PubMed

    Bodhipaksha, Laleen C; Sharpless, Charles M; Chin, Yu-Ping; MacKay, Allison A

    2017-03-01

    The photoreactivity of treated wastewater effluent organic matter differs from that of natural organic matter, and the indirect phototransformation rates of micropollutants originating in wastewater are expected to depend on the fractional contribution of wastewater to total stream flow. Photodegradation rates of four common compounds of wastewater origin (sulfamethoxazole, sulfadimethoxine, cimetidine and caffeine) were measured in river water, treated municipal wastewater effluent and mixtures of both to simulate various effluent-stream water mixing conditions that could occur in environmental systems. Compounds were chosen for their unique photodegradation pathways with the photochemically produced reactive intermediates, triplet-state excited organic matter ( 3 OM*), singlet oxygen ( 1 O 2 ), and hydroxyl radicals (OH). For all compounds, higher rates of photodegradation were observed in effluent relative to upstream river water. Sulfamethoxazole degraded primarily via direct photolysis, with some contribution from OH and possibly from carbonate radicals and other unidentified reactive intermediates in effluent-containing samples. Sulfadimethoxine also degraded mainly by direct photolysis, and natural organic matter appeared to inhibit this process to a greater extent than predicted by light screening. In the presence of effluent organic matter, sulfadimethoxine showed additional reactions with OH and 1 O 2 . In all water samples, cimetidine degraded by reaction with 1 O 2 (>95%) and caffeine by reaction with OH (>95%). In river water mixtures, photodegradation rate constants for all compounds increased with increasing fractions of effluent. A conservative mixing model was able to predict reaction rate constants in the case of hydroxyl radical reactions, but it overestimated rate constants in the case of 3 OM* and 1 O 2 pathways. Finally, compound degradation rate constants normalized to the rate of light absorption by water correlated with E 2 /E 3 ratios

  19. Storage and Bioavailability of Molybdenum in Soils Increased by Organic Matter Complexation

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

    Wichard, T.; Mishra, B; Myneni, S

    2009-01-01

    The micronutrient molybdenum is a necessary component of the nitrogen-fixing enzyme nitrogenase1, 2. Molybdenum is very rare in soils, and is usually present in a highly soluble form, making it susceptible to leaching3, 4. However, it is generally thought that molybdenum attaches to mineral surfaces in acidic soils; this would prevent its escape into the groundwater, but would also impede uptake by microbes3. Here we use X-ray spectroscopy to examine the chemical speciation of molybdenum in soil samples from forests in Arizona and New Jersey. We show that in the leaf litter layer, most of the molybdenum forms strong complexesmore » with plant-derived tannins and tannin-like compounds; molybdenum binds to these organic ligands across a wide pH range. In deeper soils, molybdenum binds to both iron oxides and natural organic matter. We suggest that the molybdenum bound to organic matter can be captured by small complexing agents that are released by nitrogen-fixing bacteria; the molybdenum can then be incorporated into nitrogenase. We conclude that the binding of molybdenum to natural organic matter helps prevent leaching of molybdenum, and is thus a critical step in securing new nitrogen in terrestrial ecosystems.« less

  20. Changes in the quality of chromophoric dissolved organic matter leached from senescent leaf litter during the early decomposition.

    PubMed

    Nishimura, Satoshi; Maie, Nagamitsu; Baba, Mitsuhisa; Sudo, Takahiro; Sugiura, Toshihiro; Shima, Eikichi

    2012-01-01

    Chromophoric dissolved organic matter (CDOM) leached from leaf litter is a major source of humus in mineral soil of forest ecosystems. While their functions and refractoriness depend on the physicochemical structure, there is little information on the quality of CDOM, especially for that leached in the very early stages of litter decomposition when a large amount of dissolved organic matter (DOM) is leached. This study aimed to better understand the variations/changes in the composition of CDOM leached from senescent leaf litter from two tree species during the early stage of decomposition. Leaf litter from a conifer tree (Japanese cedar, D. Don) and a deciduous broad-leaved tree (Konara oak, Thunb.) were incubated in columns using simulated rainfall events periodically for a total of 300 d at 20°C. The quality of CDOM was investigated based on the fluorescence properties by using a combination of excitation-emission matrix fluorescence (EEM) and parallel factor analysis (PARAFAC). In addition, the phenolic composition of DOM was investigated at a molecular level by thermally assisted hydrolysis and methylation-gas chromatography-mass spectrometry (THM-GC-MS) in the presence of tetramethylammonium hydroxide (TMAH). The EEM was statistically decomposed into eight fluorescence components (two tannin/peptide-like peaks, one protein-like peak, and five humic-like peaks). A significant contribution of tannin/peptide-like peaks was observed at the beginning of incubation, but these peaks decreased quickly and humic-like peaks increased within 1 mo of incubation. The composition of humic-like peaks was different between tree species and changed over the incubation period. Since tannin-derived phenolic compounds were detected in the DOM collected after 254 d of incubation on THM-GC-MS, it was suggested that tannins partially changed its structure, forming various humic-like peaks during the early decomposition. Copyright © by the American Society of Agronomy, Crop

  1. Transport of organic contaminants in subsoil horizons and effects of dissolved organic matter related to organic waste recycling practices.

    PubMed

    Chabauty, Florian; Pot, Valérie; Bourdat-Deschamps, Marjolaine; Bernet, Nathalie; Labat, Christophe; Benoit, Pierre

    2016-04-01

    Compost amendment on agricultural soil is a current practice to compensate the loss of organic matter. As a consequence, dissolved organic carbon concentration in soil leachates can be increased and potentially modify the transport of other solutes. This study aims to characterize the processes controlling the mobility of dissolved organic matter (DOM) in deep soil layers and their potential impacts on the leaching of organic contaminants (pesticides and pharmaceutical compounds) potentially present in cultivated soils receiving organic waste composts. We sampled undisturbed soil cores in the illuviated horizon (60-90 cm depth) of an Albeluvisol. Percolation experiments were made in presence and absence of DOM with two different pesticides, isoproturon and epoxiconazole, and two pharmaceutical compounds, ibuprofen and sulfamethoxazole. Two types of DOM were extracted from two different soil surface horizons: one sampled in a plot receiving a co-compost of green wastes and sewage sludge applied once every 2 years since 1998 and one sampled in an unamended plot. Results show that DOM behaved as a highly reactive solute, which was continuously generated within the soil columns during flow and increased after flow interruption. DOM significantly increased the mobility of bromide and all pollutants, but the effects differed according the hydrophobic and the ionic character of the molecules. However, no clear effects of the origin of DOM on the mobility of the different contaminants were observed.

  2. Lability of secondary organic particulate matter

    PubMed Central

    Liu, Pengfei; Li, Yong Jie; Wang, Yan; Gilles, Mary K.; Zaveri, Rahul A.; Bertram, Allan K.

    2016-01-01

    The energy flows in Earth’s natural and modified climate systems are strongly influenced by the concentrations of atmospheric particulate matter (PM). For predictions of concentration, equilibrium partitioning of semivolatile organic compounds (SVOCs) between organic PM and the surrounding vapor has widely been assumed, yet recent observations show that organic PM can be semisolid or solid for some atmospheric conditions, possibly suggesting that SVOC uptake and release can be slow enough that equilibrium does not prevail on timescales relevant to atmospheric processes. Herein, in a series of laboratory experiments, the mass labilities of films of secondary organic material representative of similar atmospheric organic PM were directly determined by quartz crystal microbalance measurements of evaporation rates and vapor mass concentrations. There were strong differences between films representative of anthropogenic compared with biogenic sources. For films representing anthropogenic PM, evaporation rates and vapor mass concentrations increased above a threshold relative humidity (RH) between 20% and 30%, indicating rapid partitioning above a transition RH but not below. Below the threshold, the characteristic time for equilibration is estimated as up to 1 wk for a typically sized particle. In contrast, for films representing biogenic PM, no RH threshold was observed, suggesting equilibrium partitioning is rapidly obtained for all RHs. The effective diffusion rate Dorg for the biogenic case is at least 103 times greater than that of the anthropogenic case. These differences should be accounted for in the interpretation of laboratory data as well as in modeling of organic PM in Earth’s atmosphere. PMID:27791063

  3. Lability of secondary organic particulate matter

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

    Liu, Pengfei; Li, Yong Jie; Wang, Yan

    2016-10-24

    We report the energy flows in Earth’s natural and modified climate systems are strongly influenced by the concentrations of atmospheric particulate matter (PM). For predictions of concentration, equilibrium partitioning of semivolatile organic compounds (SVOCs) between organic PM and the surrounding vapor has widely been assumed, yet recent observations show that organic PM can be semisolid or solid for some atmospheric conditions, possibly suggesting that SVOC uptake and release can be slow enough that equilibrium does not prevail on timescales relevant to atmospheric processes. Herein, in a series of laboratory experiments, the mass labilities of films of secondary organic material representativemore » of similar atmospheric organic PM were directly determined by quartz crystal microbalance measurements of evaporation rates and vapor mass concentrations. There were strong differences between films representative of anthropogenic compared with biogenic sources. For films representing anthropogenic PM, evaporation rates and vapor mass concentrations increased above a threshold relative humidity (RH) between 20% and 30%, indicating rapid partitioning above a transition RH but not below. Below the threshold, the characteristic time for equilibration is estimated as up to 1 wk for a typically sized particle. In contrast, for films representing biogenic PM, no RH threshold was observed, suggesting equilibrium partitioning is rapidly obtained for all RHs. The effective diffusion rate D org for the biogenic case is at least 10 3 times greater than that of the anthropogenic case. In conclusion, these differences should be accounted for in the interpretation of laboratory data as well as in modeling of organic PM in Earth’s atmosphere.« less

  4. Impact of natural organic matter properties on the kinetics of suspended ion exchange process.

    PubMed

    Bazri, Mohammad Mahdi; Mohseni, Madjid

    2016-03-15

    Removal kinetics of four standard organic matter isolates under the application of strongly basic ion exchange resins (IEX) in suspended mode was studied under commercial application conditions. Suwannee River natural organic matter (SRNOM), SR fulvic acid (SRFA), and Pony Lake fulvic acid (PLFA) were greatly removed (>90%) and highly preferred by IEX resins (α > 5, over Cl(-), and HCO3(-)) while SR humic acid (SRHA) was the least preferred organic structure among the four isolates studied (α ≈ 1). Moreover, the efficacy of removal for fulvic acids (i.e., SRFA, PLFA) was consistent over consecutive reuse of IEX resins (i.e., loading cycles) whereas it decreased for SRNOM and SRHA over the course of operation. The stoichiometric correlation between the chloride released from the resins as a result of organic molecules uptake indicated that ion exchange was the dominant mechanism. Results obtained indicated that molecular weight and charge density of isolates played a major role in the performance of ion exchange process for organic matter removal. Furthermore, various empirical and physical models were evaluated using the experimental data and pore diffusion was found to be the rate-liming step during the uptake of organic matters; hence, it was used as the appropriate model to predict the kinetics of removal. Consequently, free liquid diffusivities and effective pore diffusion coefficients of organic molecules were estimated and findings were in agreement with the literature data that were obtained from spectrophotometric methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Global Warming Potential from early phase decomposition of soil organic matter amendments

    NASA Astrophysics Data System (ADS)

    Mayer, A.; Silver, W. L.

    2015-12-01

    Organic matter amendments to soil are widely used as a method of enhancing nutrient availability for crops or grassland. Amendments such as composted manure or greenwaste also have the co-benefits of potentially increasing soil carbon (C) stocks (DeLonge et al., 2013) and diverting organic waste from landfills or manure lagoons. However, application of organic matter amendments can also stimulate emissions of greenhouse gases (GHGs). In this study we determined how the chemical quality of organic matter amendments affected soil C and N content and GHG emissions during early stage decomposition. California grassland soils were amended with six different amendments of varying C and N content including three composts and three feedstocks (goat and horse bedding and cattle manure). Amendments and soils were incubated in the laboratory for 7 weeks; GHG fluxes were measured weekly. The three feedstocks emitted significantly more GHGs than the composted materials. With the exception of cow manure, N content of the amendment was linearly correlated with global warming potential emitted (R2= 0.66, P <0.0001). C:N ratios were not a significant predictor of GHG emissions. Cow manure stimulated a net loss of C (or C equivalents) in the mineral soil, as expected. However, greenwaste compost also surprisingly resulted in net C losses, while goat bedding, horse bedding, and the other compost were either C neutral or a slight net C sink at the end of the incubation. Ongoing analyses are examining the fate of the C incorporated from the amendment to the soil as occluded or free light fraction, as well as N mineralization rates. Our data suggest that N content of organic matter amendments is a good predictor of initial GHG emissions. The study also indicates that composting greenwaste with N-rich bedding and manure can result in lower GHG emissions and C sequestration compared to the individual uncomposted components.

  6. Dissolved organic matter (DOM) in microalgal photobioreactors: a potential loss in solar energy conversion?

    PubMed

    Hulatt, Chris J; Thomas, David N

    2010-11-01

    Microalgae are considered to be a potential alternative to terrestrial crops for bio-energy production due to their relatively high productivity per unit area of land. In this work we examined the amount of dissolved organic matter exuded by algal cells cultured in photobioreactors, to examine whether a significant fraction of the photoassimilated biomass could potentially be lost from the harvestable biomass. We found that the mean maximum amount of dissolved organic carbon (DOC) released measured 6.4% and 17.3% of the total organic carbon in cultures of Chlorellavulgaris and Dunaliella tertiolecta, respectively. This DOM in turn supported a significant growth of bacterial biomass, representing a further loss of the algal assimilated carbon. The release of these levels of DOC indicates that a significant fraction of the photosynthetically fixed organic matter could be lost into the surrounding water, suggesting that the actual biomass yield per hectare for industrial purposes could be somewhat less than expected. A simple and inexpensive optical technique, based on chromophoric dissolved organic matter (CDOM) measurements, to monitor such losses in commercial PBRs is discussed.

  7. Exoenzyme activities as indicators of dissolved organic matter composition in the hyporheic zone of a floodplain river

    Treesearch

    Sandra M. Clinton; Rick T. Edwards; Stuart E.G. Findlay

    2010-01-01

    We measured the hyporheic microbial exoenzyme activities in a floodplain river to determine whether dissolved organic matter (DOM) bioavailability varied with overlying riparian vegetation patch structure or position along flowpaths. Particulate organic matter (POM), dissolved organic carbon (DOC), dissolved oxygen (DO), electrical conductivity and temperature were...

  8. FACTORS INFLUENCING PHOTOREACTIONS OF DISSOLVED ORGANIC MATTER IN A COASTAL RIVER OF THE SOUTHEASTERN UNITED STATES

    EPA Science Inventory

    Photoreactions of dissolved organic matter can affect the oxidizing capacity, nutrient dynamics, trace gas exchange, and color of surface waters. This study focuses on factors that affect the photoreactions of the colored dissolved organic matter (CDOM) in the Satilla River, a co...

  9. Using organic matter to increase soil fertility in Burundi: potentials and limitations

    NASA Astrophysics Data System (ADS)

    Kaboneka, Salvator

    2015-04-01

    Agriculture production in Burundi is dominated by small scale farmers (0.5 ha/household) who have only very limited access to mineral inputs. In the past, farmers have relied on fallow practices combined with farm yard manures to maintain and improve soil fertility. However, due to the high population growth and high population density (370/km²), fallow practices are nowadays no longer feasible, animal manures cannot be produced in sufficient quantities to maintain soil productivity and food insecurity has become a quasi permanent reality. Most Burundian soils are characterized by 1:1 types of clay minerals (kaolinite) and are acidic in nature. Such soils are of very low cation exchange capacity (CEC). To compare the effect of % clays and % organic matter (% C), correlations tests have been conducted between the two parameters and the CEC. It was found that in high altitude kaolinitic and acidic soils, CEC was highly correlated to % C and less correlated to % clay, suggesting that organic matter could play an important role in improving fertility and productivity of these soils. Based on these findings, additional studies have been conducted to evaluate the fertilizer and soil amendment values of animal manures (cattle, goat, chicken), and leguminous (Calliandra calothyrsus, Gliricidia sepium, Senna simea, Senna spectabilis) and non-leguminous (Tithonia diversifolia) foliar biomass. It was observed that chicken manure significantly reduces Al3+ levels in acidic soils, while Tithonia diversifolia outperforms in nutrient releases compared to the commonly known leguminous agroforestry shrubs and trees indicated above. Although the above mentioned organic sources can contribute to the soil nutrients supply, the quantities potentially available on farm are generally small. The only solution is to supplement these organic sources with other organic sources (compost, organic household waste), chemical fertilizers and mineral amendments (lime) to achieve Integrated Soil

  10. Distribution and source of organic matter in surface sediment from the muddy deposit along the Zhejiang coast, East China Sea.

    PubMed

    Xu, Gang; Liu, Jian; Hu, Gang; Jonell, Tara N; Chen, Lilei

    2017-10-15

    To constrain organic matter compositions and origins, elemental (TOC, TN, C/N) and stable carbon (δ 13 C) and nitrogen isotope (δ 15 N) compositions are measured for surface sediments collected from muddy deposit along the Zhejiang coast, East China Sea. The results showed that the TOC, TN, C/N, δ 13 C, and δ 15 N were 0.19-0.67%, 0.03-0.09%, 6.76-9.22, -23.43 to -20.26‰, and 3.93-5.27‰, respectively. The δ 13 C values showed that the mixing inputs of terrigenous and marine organic matter generally dominated sedimentary organic matter in the west part, and the sedimentary organic matters were mainly influenced by the marine organic matter in the east part of the study area. A stable carbon isotope two end member mixing model estimates ~38% terrestrial -derived and ~62% marine-derived inputs to sedimentary organic matter. Microbial mineralization strongly controls δ 15 N values, and therefore cannot be used to identify the provenance of organic matter for the Zhenjiang coast. Copyright © 2017. Published by Elsevier Ltd.

  11. Effect of soil pH and organic matter on the adsorption and desorption of pentachlorophenol.

    PubMed

    Chien, Shui-Wen Chang; Chen, Shou-Hung; Li, Chi-Jui

    2018-02-01

    Various properties of soil affect the partition of organic contaminants within, and conversely, the properties of the organic contaminants also directly affect their partition behavior in soil. Therefore, understanding the effects of various properties of soil on the partition of organic contaminants favors subsequent assessment and provides soil remediation methods for policymakers. This study selected pentachlorophenol (PCP), a common hydrophobic ionizable organic compound in contaminated sites worldwide, as the target contaminant. The effects of pH, organic matter, and the combination of both, on PCP adsorption/desorption behavior in soil were investigated. Phosphoric acid and potassium hydroxide were used as buffer solutions to modify the soil pH by the batch and column extraction methods. A common retail organic fertilizer and fulvic acid were selected as additives to manipulate the soil organic content. Modifying the pH of the soil samples revealed that acidic soil exhibited a greater PCP adsorption rate than alkaline soil. The amount of PCP desorption increased regardless of pH of the in situ contaminated soil. The adsorption of PCP increased with increasing amount of organic additive. However, addition of fulvic acid yielded different results compared to the addition of organic fertilizer. Specifically, the organic fertilizer could not compete with the in situ contaminated soil in PCP adsorption, whereas fulvic acids increased the PCP dissolution to facilitate adsorbing contaminant adsorption. The combined effect of pH modification and organic matter addition provides additional PCP adsorption sites; therefore, adding the organic fertilizer to decrease the soil pH elevated the PCP adsorption rates of the laterite, alluvial, and in situ contaminated soil samples. The study results revealed that both pH and organic matter content are crucial to PCP adsorption/desorption in soil. Therefore, the effects of soil pH and organic matter should be considered in

  12. Organic matter and soil structure in the Everglades Agricultural Area

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

    Wright, Alan L.; Hanlon, Edward A.

    This publication pertains to management of organic soils (Histosols) in the Everglades Agricultural Area (EAA). These former wetland soils are a major resource for efficient agricultural production and are important globally for their high organic matter content. Recognition of global warming has led to considerable interest in soils as a repository for carbon. Soils rich in organic matter essentially sequester or retain carbon in the profile and can contribute directly to keeping that sequestered carbon from entering the atmosphere. Identification and utilization of management practices that minimize the loss of carbon from organic soils to the atmosphere can minimize effectsmore » on global warming and increase the longevity of subsiding Histosols for agricultural use. Understanding and predicting how these muck soils will respond to current and changing land uses will help to manage soil carbon. The objectives of this document are to: a. Discuss organic soil oxidation relative to storing or releasing carbon and nitrogen b. Evaluate effects of cultivation (compare structure for sugarcane vs. uncultivated soil) Based upon the findings from the land-use comparison (sugarcane or uncultivated), organic carbon was higher with cultivation in the lower depths. There is considerable potential for minimum tillage and residue management to further enhance carbon sequestration in the sugarcane system. Carbon sequestration is improved and soil subsidence is slowed with sugarcane production, and both of these are positive outcomes. Taking action to increase or maintain carbon sequestration appears to be appropriate but may introduce some risk to farming operations. Additional management methods are needed to reduce this risk. For both the longevity of these organic soils and from a global perspective, slowing subsidence through BMP implementation makes sense. Since these BMPs also have considerable societal benefit, it remains to be seen if society will help to offset a

  13. A review of observations of organic matter in fogs and clouds: Origin, processing and fate

    NASA Astrophysics Data System (ADS)

    Herckes, Pierre; Valsaraj, Kalliat T.; Collett, Jeffrey L.

    2013-10-01

    While fog and cloud composition has been studied for decades, most of the research was limited to inorganic species and fog acidity. Recently the focus has shifted towards organic matter in the atmospheric aqueous phase of fogs and clouds: its origin, reactivity and fate. An impressive number of fog and cloud chemistry observational studies have been performed over the last decade throughout the world. In the present work we will review the state of knowledge of atmospheric organic matter processing by fogs, with a focus on field observations. We start by reviewing observational studies in general and then discuss our knowledge on the occurrence of organic matter in fogs, its solubility, characterization and molecular speciation. Organic carbon concentrations can vary widely from approximately 1 mg C/L in remote marine environments to more than 100 mg C/L in polluted radiation fogs, accounting for a substantial part of fogwater solutes. The carbonaceous material can enter the droplets from the gas and particle phase and the scavenging behavior of fogs will be detailed. Observational studies showed evidence of aqueous phase transformation of organic material, in particular secondary organic aerosol (SOA) generation, in fog. Recent observations of biological material in fog suggest also an impact of biological processing within the droplets on fog organic matter. The review will end with a discussion of the impact of fog on the deposition fluxes of organic material and hence its atmospheric lifetime.

  14. Radiocarbon and stable carbon isotope compositions of chemically fractionated soil organic matter in a temperate-zone forest.

    PubMed

    Koarashi, Jun; Iida, Takao; Asano, Tomohiro

    2005-01-01

    To better understand the role of soil organic matter in terrestrial carbon cycle, carbon isotope compositions in soil samples from a temperate-zone forest were measured for bulk, acid-insoluble and base-insoluble organic matter fractions separated by a chemical fractionation method. The measurements also made it possible to estimate indirectly radiocarbon ((14)C) abundances of acid- and base-soluble organic matter fractions, through a mass balance of carbon among the fractions. The depth profiles of (14)C abundances showed that (1) bomb-derived (14)C has penetrated the first 16cm mineral soil at least; (2) Delta(14)C values of acid-soluble organic matter fraction are considerably higher than those of other fractions; and (3) a significant amount of the bomb-derived (14)C has been preserved as the base-soluble organic matter around litter-mineral soil boundary. In contrast, no or little bomb-derived (14)C was observed for the base-insoluble fraction in all sampling depths, indicating that this recalcitrant fraction, accounting for approximately 15% of total carbon in this temperate-zone forest soil, plays a role as a long-term sink in the carbon cycle. These results suggest that bulk soil organic matter cannot provide a representative indicator as a source or a sink of carbon in soil, particularly on annual to decadal timescales.

  15. Geochemical characteristics of organic matter in the Andaman Sea sediments: Implications for source, paleovegetation and paleoclimate changes

    NASA Astrophysics Data System (ADS)

    Hossain, H. M. Z.; Sampei, Y.; Kawahata, H.

    2016-12-01

    The distribution, source, and redox variation of sedimentary organic matter in the Andaman Sea is significant for understanding its biogeochemical cycle, which we determined the total organic carbon (TOC), total nitrogen (TN), and n-alkanes contents. TOC and TN concentrations varied from 0.61 to 1.18 wt.% (average 0.87 wt.%) and 0.07 to 0.17 wt.% (average 0.13 wt.%), respectively with high TOC in the clay-rich sediments indicate hydrodynamic sorting readily controlled TOC abundances. Bulk C/N ratio (5.51 to 11.92, average 7.89) is attributed to the high inputs of organic matter from planktonic sources and an appreciable amounts of terrestrial derived organic matter. n-Alkane distributions from the Andaman Sea sediment cores are characterized mainly by C17 to C35, with odd-over-even predominance suggest a diverse origin of organic matter. High relative abundances of mid-chain n-alkanes of C23 and C25 recorded in the samples that are characteristically derived from submerges/floating aquatic macrophytes. However, odd long-chain n-alkanes from C27 to C33 with high peaks at C29 and C31 were detected in the samples reflecting a terrigenous origin of organic matter. The average chain length (ACL), carbon preference index (CPI), Paq and Pwax ratio values further suggested that major influence of organic matter from non-emergent aquatic macrophytes together significant proportions of grasses and herbs. Low Pr/Ph and Tm/Ts ratios in most section implying a more reducing to suboxic conditions prevailed during organic matter preservation in the oceanic event. However, high ACL values and low Paq values in the down-core variation could suggest initially cold and dry climates and gradually shifted to warm and humid conditions.

  16. Synthesis of refractory materials

    DOEpatents

    Holt, Joseph B.

    1984-01-01

    Refractory metal nitrides are synthesized during a combustion process utilizing a solid source of nitrogen. For this purpose, a metal azide is employed. The azide is combusted with a transition metal of the IIIB, IVB group, or a rare earth metal, and ignited to produce the refractory material.

  17. Synthesis of refractory materials

    DOEpatents

    Holt, J.B.

    Refractory metal nitrides are synthesized during a combustion process utilizing a solid source of nitrogen. For this purpose, a metal azide is employed. The azide is combusted with a transition metal of the IIIB, IVB group, or a rare earth metal, and ignited to produce the refractory material.

  18. The abiotic degradation of soil organic matter to oxalic acid

    NASA Astrophysics Data System (ADS)

    Studenroth, Sabine; Huber, Stefan; Schöler, H. F.

    2010-05-01

    The abiotic degradation of soil organic matter to volatile organic compounds was studied intensely over the last years (Keppler et al., 2000; Huber et al., 2009). It was shown that soil organic matter is oxidised due to the presence of iron (III), hydrogen peroxide and chloride and thereby produces diverse alkyl halides, which are emitted into the atmosphere. The formation of polar halogenated compounds like chlorinated acetic acids which are relevant toxic environmental substances was also found in soils and sediments (Kilian et al., 2002). The investigation of the formation of other polar halogenated and non-halogenated compounds like diverse mono- and dicarboxylic acids is going to attain more and more importance. Due to its high acidity oxalic acid might have impacts on the environment e.g., nutrient leaching, plant diseases and negative influence on microbial growth. In this study, the abiotic formation of oxalic acid in soil is examined. For a better understanding of natural degradation processes mechanistic studies were conducted using the model compound catechol as representative for structural elements of the humic substances and its reaction with iron (III) and hydrogen peroxide. Iron is one of the most abundant elements on earth and hydrogen peroxide is produced by bacteria or through incomplete reduction of oxygen. To find suitable parameters for an optimal reaction and a qualitative and quantitative analysis method the following reaction parameters are varied: concentration of iron (III) and hydrogen peroxide, time dependence, pH-value and influence of chloride. Analysis of oxalic acid was performed employing an ion chromatograph equipped with a conductivity detector. The time dependent reaction shows a relatively fast formation of oxalic acid, the optimum yield is achieved after 60 minutes. Compared to the concentration of catechol an excess of hydrogen peroxide as well as a low concentration of iron (III) are required. In absence of chloride the

  19. Organic matter in meteorites and comets - Possible origins

    NASA Technical Reports Server (NTRS)

    Anders, Edward

    1991-01-01

    At least six extraterrestrial environments may have contributed organic compounds to meteorites and comets: solar nebula, giant-planet subnebulae, asteroid interiors containing liquid water, carbon star atmospheres, and diffuse or dark interstellar clouds. The record in meteorites is partly obscured by pervasive reheating that transformed much of the organic matter to kerogen; nonetheless, it seems that all six formation sites contributed. For comets, the large abundance of HCHO, HCN, and unsaturated hydrocarbons suggests an interstellar component of 50 percent or more, but the contributions of various interstellar processes, and of a solar-nebula component, are hard to quantify. A research program is outlined that may help reduce these uncertainties.

  20. Advances in understanding the molecular structure of soil organic matter: Implications for interactions in the environment

    EPA Science Inventory

    We take a historic approach to explore how concepts of the chemical and physical nature of soil organic matter have evolved over time. We emphasize conceptual and analytical achievements in organic matter research over the last two decades and demonstrate how these developments h...

  1. [Spatial interpolation of soil organic matter using regression Kriging and geographically weighted regression Kriging].

    PubMed

    Yang, Shun-hua; Zhang, Hai-tao; Guo, Long; Ren, Yan

    2015-06-01

    Relative elevation and stream power index were selected as auxiliary variables based on correlation analysis for mapping soil organic matter. Geographically weighted regression Kriging (GWRK) and regression Kriging (RK) were used for spatial interpolation of soil organic matter and compared with ordinary Kriging (OK), which acts as a control. The results indicated that soil or- ganic matter was significantly positively correlated with relative elevation whilst it had a significantly negative correlation with stream power index. Semivariance analysis showed that both soil organic matter content and its residuals (including ordinary least square regression residual and GWR resi- dual) had strong spatial autocorrelation. Interpolation accuracies by different methods were esti- mated based on a data set of 98 validation samples. Results showed that the mean error (ME), mean absolute error (MAE) and root mean square error (RMSE) of RK were respectively 39.2%, 17.7% and 20.6% lower than the corresponding values of OK, with a relative-improvement (RI) of 20.63. GWRK showed a similar tendency, having its ME, MAE and RMSE to be respectively 60.6%, 23.7% and 27.6% lower than those of OK, with a RI of 59.79. Therefore, both RK and GWRK significantly improved the accuracy of OK interpolation of soil organic matter due to their in- corporation of auxiliary variables. In addition, GWRK performed obviously better than RK did in this study, and its improved performance should be attributed to the consideration of sample spatial locations.

  2. Organic matter in a coal ball: Peat or coal?

    USGS Publications Warehouse

    Hatcher, P.G.; Lyons, P.C.; Thompson, C.L.; Brown, F.W.; Maciel, G.E.

    1982-01-01

    Chemical analyses of morphologically preserved organic matter in a Carboniferous coal ball reveal that the material is coalified to a rank approximately equal to that of the surrounding coal. Hence, the plant tissues in the coal ball were chemically altered by coalification processes and were not preserved as peat. Copyright ?? 1982 AAAS.

  3. Lyophilization and Reconstitution of Reverse Osmosis Concentrated Natural Organic Matter

    EPA Science Inventory

    Disinfection by-product (DBP) research can be complicated by difficulties in shipping large water quantities and changing natural organic matter (NOM) characteristics over time. To overcome these issues, it is advantageous to have a reliable method for concentrating and preservin...

  4. Ecogeomorphology of Spartina patens-dominated tidal marshes: Soil organic matter accumulation, marsh elevation dynamics, and disturbance

    USGS Publications Warehouse

    Cahoon, D.R.; Ford, M.A.; Hensel, P.F.; Fagherazzi, Sergio; Marani, Marco; Blum, Linda K.

    2004-01-01

    Marsh soil development and vertical accretion in Spartina patens (Aiton) Muhl.-dominated tidal marshes is largely dependent on soil organic matter accumulation from root-rhizome production and litter deposition. Yet there are few quantitative data sets on belowground production and the relationship between soil organic matter accumulation and soil elevation dynamics for this marsh type. Spartina patens marshes are subject to numerous stressors, including sea-level rise, water level manipulations (i.e., flooding and draining) by impoundments, and prescribed burning. These stressors could influence long-term marsh sustainability by their effect on root production, soil organic matter accumulation, and soil elevation dynamics. In this review, we summarize current knowledge on the interactions among vegetative production, soil organic matter accumulation and marsh elevation dynamics, or the ecogeomorphology, of Spartina patens-dominated tidal marshes. Additional studies are needed of belowground production/decomposition and soil elevation change (measured simultaneously) to better understand the links among soil organic matter accumulation, soil elevation change, and disturbance in this marsh type. From a management perspective, we need to better understand the impacts of disturbance stressors, both lethal and sub-lethal, and the interactive effect of multiple stressors on soil elevation dynamics in order to develop better management practices to safeguard marsh sustainability as sea level rises.

  5. Effect of Natural Organic Matter on the Light-initiated Transformation of Fullerenes

    EPA Science Inventory

    Natural organic matter (NOM) is ubiquitous in natural environments. Previous research has observed enhanced dispersion of Buckminster fullerene (C60) in water in the presence of NOM. It is also well-known that NOM can impact the photoreaction of many organic compounds by producin...

  6. Clinical Investigation of Refractory Chronic Subdural Hematoma: A Comparison of Clinical Factors Between Single and Repeated Recurrences.

    PubMed

    Matsumoto, Hiroaki; Hanayama, Hiroaki; Okada, Takashi; Sakurai, Yasuo; Minami, Hiroaki; Masuda, Atsushi; Tominaga, Shogo; Miyaji, Katsuya; Yamaura, Ikuya; Yoshida, Yasuhisa; Yoshida, Kozo

    2017-11-01

    Chronic subdural hematoma (CSDH) is sometimes refractory, and this is troublesome for neurosurgeons. Although many studies have reported risk factors or treatments in efforts to prevent recurrence, those have focused on single recurrence, and few cumulative data are available to analyze refractory CSDH. We defined refractory CSDH as ≥2 recurrences, then analyzed and compared clinical factors between patients with single recurrence and those with refractory CSDH in a cohort study, to clarify whether patients with refractory CSDH experience different or more risk factors than patients with single recurrence, and whether burr-hole irrigation with closed-system drainage reduces refractory CSDH. Seventy-five patients had at least 1 recurrence, with single recurrence in 62 patients and ≥2 recurrences in 13 patients. In comparing clinical characteristics, patients with refractory CSDH were significantly younger (P = 0.04) and showed shorter interval to first recurrence (P < 0.001). Organized CSDH was also significantly associated with refractory CSDH (P = 0.02). Multivariate logistic regression analysis identified first recurrence interval <1 month (odds ratio, 6.66, P < 0.001) and age <71 years (odds ratio, 4.16, P < 0.001) as independent risk factors for refractory CSDH. On the other hand, burr-hole irrigation with closed-system drainage did not reduce refractory CSDH. When patients with risk factors for refractory CSDH experience recurrence, alternative surgical procedures may be considered as the second surgery, because burr-hole irrigation with closed-system drainage did not reduce refractory CSDH in our study. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Organic matter dynamics and stable isotope signature as tracers of the sources of suspended sediment

    NASA Astrophysics Data System (ADS)

    Schindler Wildhaber, Y.; Liechti, R.; Alewell, C.

    2012-06-01

    Suspended sediment (SS) and organic matter in rivers can harm brown trout Salmo trutta by affecting the health and fitness of free swimming fish and by causing siltation of the riverbed. The temporal and spatial dynamics of sediment, carbon (C), and nitrogen (N) during the brown trout spawning season in a small river of the Swiss Plateau were assessed and C isotopes as well as the C/N atomic ratio were used to distinguish autochthonous and allochthonous sources of organic matter in SS loads. The visual basic program IsoSource with 13Ctot and 15N as input isotopes was used to quantify the temporal and spatial sources of SS. Organic matter concentrations in the infiltrated and suspended sediment were highest during low flow periods with small sediment loads and lowest during high flow periods with high sediment loads. Peak values in nitrate and dissolved organic C were measured during high flow and high rainfall, probably due to leaching from pasture and arable land. The organic matter was of allochthonous sources as indicated by the C/N atomic ratio and δ13Corg. Organic matter in SS increased from up- to downstream due to an increase of pasture and arable land downstream of the river. The mean fraction of SS originating from upper watershed riverbed sediment decreased from up to downstream and increased during high flow at all measuring sites along the course of the river. During base flow conditions, the major sources of SS are pasture, forest and arable land. The latter increased during rainy and warmer winter periods, most likely because both triggered snow melt and thus erosion. The measured increase in DOC and nitrate concentrations during high flow support these modeling results. Enhanced soil erosion processes on pasture and arable land are expected with increasing heavy rain events and less snow during winter seasons due to climate change. Consequently, SS and organic matter in the river will increase, which will possibly affect brown trout negatively.

  8. Fire effects on soil organic matter content, composition, and nutrients in boreal interior Alaska

    USGS Publications Warehouse

    Neff, J.C.; Harden, J.W.; Gleixner, G.

    2005-01-01

    Boreal ecosystems contain a substantial fraction of the earth's soil carbon stores and are prone to frequent and severe wildfires. In this study, we examine changes in element and organic matter stocks due to a 1999 wildfire in Alaska. One year after the wildfire, burned soils contained between 1071 and 1420 g/m2 less carbon than unburned soils. Burned soils had lower nitrogen than unburned soils, higher calcium, and nearly unchanged potassium, magnesium, and phosphorus stocks. Burned surface soils tended to have higher concentrations of noncombustible elements such as calcium, potassium, magnesium, and phosphorus compared with unburned soils. Combustion losses of carbon were mostly limited to surface dead moss and fibric horizons, with no change in the underlying mineral horizons. Burning caused significant changes in soil organic matter structure, with a 12% higher ratio of carbon to combustible organic matter in surface burned horizons compared with unburned horizons. Pyrolysis gas chromatography - mass spectroscopy also shows preferential volatilization of polysaccharide-derived organic matter and enrichment of lignin-and lipid-derived compounds in surface soils. The chemistry of deeper soil layers in burned and unburned sites was similar, suggesting that immediate fire impacts were restricted to the surface soil horizon. ?? 2005 NRC.

  9. Soil Organic Matter in Its Native State: Unravelling the Most Complex Biomaterial on Earth.

    PubMed

    Masoom, Hussain; Courtier-Murias, Denis; Farooq, Hashim; Soong, Ronald; Kelleher, Brian P; Zhang, Chao; Maas, Werner E; Fey, Michael; Kumar, Rajeev; Monette, Martine; Stronks, Henry J; Simpson, Myrna J; Simpson, André J

    2016-02-16

    Since the isolation of soil organic matter in 1786, tens of thousands of publications have searched for its structure. Nuclear magnetic resonance (NMR) spectroscopy has played a critical role in defining soil organic matter but traditional approaches remove key information such as the distribution of components at the soil-water interface and conformational information. Here a novel form of NMR with capabilities to study all physical phases termed Comprehensive Multiphase NMR, is applied to analyze soil in its natural swollen-state. The key structural components in soil organic matter are identified to be largely composed of macromolecular inputs from degrading biomass. Polar lipid heads and carbohydrates dominate the soil-water interface while lignin and microbes are arranged in a more hydrophobic interior. Lignin domains cannot be penetrated by aqueous solvents even at extreme pH indicating they are the most hydrophobic environment in soil and are ideal for sequestering hydrophobic contaminants. Here, for the first time, a complete range of physical states of a whole soil can be studied. This provides a more detailed understanding of soil organic matter at the molecular level itself key to develop the most efficient soil remediation and agricultural techniques, and better predict carbon sequestration and climate change.

  10. Influence of organic matter on trace metal flux in coastal sediments. [Sequim Bay

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

    Schmidt, R.L.; Gibson, C.I.

    1978-05-15

    These studies indicate that organic matter in coastal sediment constitutes a primary sink for trace metals, both at natural and amended levels. Organic substances are also involved in controlling the mobility and flux of trace metals from sediments. Further, organically-bound trace metals in sediments appear to be an important source to deposit-feeding organisms.

  11. Temperature-driven decoupling of key phases of organic matter degradation in marine sediments.

    PubMed

    Weston, Nathaniel B; Joye, Samantha B

    2005-11-22

    The long-term burial of organic carbon in sediments results in the net accumulation of oxygen in the atmosphere, thereby mediating the redox state of the Earth's biosphere and atmosphere. Sediment microbial activity plays a major role in determining whether particulate organic carbon is recycled or buried. A diverse consortium of microorganisms that hydrolyze, ferment, and terminally oxidize organic compounds mediates anaerobic organic matter mineralization in anoxic sediments. Variable temperature regulation of the sequential processes, leading from the breakdown of complex particulate organic carbon to the production and subsequent consumption of labile, low-molecular weight, dissolved intermediates, could play a key role in controlling rates of overall organic carbon mineralization. We examined sediment organic carbon cycling in a sediment slurry and in flow through bioreactor experiments. The data show a variable temperature response of the microbial functional groups mediating organic matter mineralization in anoxic marine sediments, resulting in the temperature-driven decoupling of the production and consumption of organic intermediates. This temperature-driven decoupling leads to the accumulation of labile, low-molecular weight, dissolved organic carbon at low temperatures and low-molecular weight dissolved organic carbon limitation of terminal metabolism at higher temperatures.

  12. Long-term citrus organic farming strategy results in soil organic matter recovery

    NASA Astrophysics Data System (ADS)

    Novara, Agata; Pereira, Paulo; Barone, Ettore; Giménez Morera, Antonio; Keesstra, Saskia; Gristina, Luciano; Jordán, Antonio; Parras-Alcantara, Luis; Cerdà, Artemi

    2017-04-01

    ABSTRACT Soils play a key role in the Earth System (Keesstra et al., 2012; Brevick et al., 2015). Soils are a key resource for the human societies (Mol and Keesstra, 2012) and they are relevant to achieve the sustainability such as the United Nations Goals highlight (Keesstra et al., 2016). Agriculture soils, especially those under conventional tillage, are prone to organic matter mineralization, soil erosion, compaction and increase of greenhouse gases emission (Novara et al., 2011; Bruun et al., 2015; de Moraes et al., 2015; Choudhury et al., 2016; del Mar et al., 2016). The adoption of organic farming and sustainable management practices may provide a sustainable crop productivity, and in the meanwhile mitigate the negative impact of agriculture on ecosystem services benefits (Laudicina et al., 2015; Parras-Alcantara et al., 2015; 2016). The aim of this study was to examine, under field conditions, the long-term changes of soil organic matter under organic farming management in citrus orchards in Mediterranean environment and evaluate the ecosystem service on C sequestration in terms of economic benefits. The research was carried out at the Alcoleja Experimental Station located in the Cànyoles river watershed in the Eastern Spain on 45year old citrus plantation. Soil Organic Matter (SOM) content was monitored for 20 years at 6 different soil depth. The profitability of citrus plantation was estimated under conventional and organic management. Results showed that SOM in the 0-30 cm soil depth was the double after 20 years of organic farming management, ranging from 0.8 g kg-1 in 1995 to 1.5 g kg-1 in 2006. The highest SOM increase was in the top soil layer (368% of SOM increase in comparison to the initial SOM content) and decreased with soil depth. The effect of organic farming was relevant after 5 years since land management change, indicating that in Mediterranean environment the duration of long term studies should be higher than five years and proper policy

  13. Management of refractory epilepsy.

    PubMed

    Muñana, Karen R

    2013-05-01

    The term refractory epilepsy is utilized in veterinary medicine to describe a condition in which an animal with epilepsy fails to attain satisfactory seizure control or suffers intolerable side effects despite appropriate therapy with conventional antiepileptic drugs. Refractory epilepsy is an important problem in small animal practice as it occurs in approximately one-third of dogs with epilepsy. Consequently, there is much interest in identifying ways to more effectively treat this population of animals. More than a dozen new antiepileptic drugs have been approved for humans over the last 2 decades, and several of these drugs, including gabapentin, zonisamide, levetiracetam, and pregabalin, have been evaluated for the treatment of refractory seizures in veterinary patients. Nonmedical methods to treat poorly controlled epilepsy are also being explored. The 2 alternative forms of therapy that have shown the most promise in humans with epilepsy are electrical stimulation of the brain and dietary modification, both of which have also been evaluated in dogs. This overview summarizes the available data on pharmacologic as well as nonmedical treatment options for dogs and cats with refractory epilepsy. Although many forms of therapy are currently being utilized in clinical practice, our knowledge of the safety and efficacy of these treatments is limited. Additional randomized controlled trials are needed to better evaluate these novel therapies for refractory epilepsy in dogs and cats. © 2013 Elsevier Inc. All rights reserved.

  14. Social dynamics within decomposer communities lead to nitrogen retention and organic matter build-up in soils

    PubMed Central

    Kaiser, Christina; Franklin, Oskar; Richter, Andreas; Dieckmann, Ulf

    2015-01-01

    The chemical structure of organic matter has been shown to be only marginally important for its decomposability by microorganisms. The question of why organic matter does accumulate in the face of powerful microbial degraders is thus key for understanding terrestrial carbon and nitrogen cycling. Here we demonstrate, based on an individual-based microbial community model, that social dynamics among microbes producing extracellular enzymes (‘decomposers') and microbes exploiting the catalytic activities of others (‘cheaters') regulate organic matter turnover. We show that the presence of cheaters increases nitrogen retention and organic matter build-up by downregulating the ratio of extracellular enzymes to total microbial biomass, allowing nitrogen-rich microbial necromass to accumulate. Moreover, increasing catalytic efficiencies of enzymes are outbalanced by a strong negative feedback on enzyme producers, leading to less enzymes being produced at the community level. Our results thus reveal a possible control mechanism that may buffer soil CO2 emissions in a future climate. PMID:26621582

  15. Effects of salinity and organic matter on the partitioning of perfluoroalkyl acid (PFAs) to clay particles.

    PubMed

    Jeon, Junho; Kannan, Kurunthachalam; Lim, Byung J; An, Kwang Guk; Kim, Sang Don

    2011-06-01

    The influence of salinity and organic matter on the distribution coefficient (K(d)) for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in a brackish water-clay system was studied. The distribution coefficients (K(d)) for PFAs onto inorganic clay surfaces increased with salinity, providing evidence for electrostatic interaction for the sorption of PFAs, whereas the relationship between K(d) and organic carbon content (f(oc)) suggested that hydrophobic interaction is the primary driving force for the sorption of PFAs onto organic matter. The organic carbon normalized adsorption coefficient (K(oc)) of PFAs can be slightly overestimated due to the electrostatic interaction within uncoated inorganic surfaces. In addition, the dissolved organic matter released from coated clay particles seemed to solvate PFA molecules in solution, which contributed to a decrease in K(d). A positive relationship between K(d) and salinity was apparent, but an empirical relationship for the 'salting-out' effect was not evident. The K(d) values of PFAs are relatively small compared with those reported for persistent organic pollutants. Thus, sorption may not be a significant route of mass transfer of PFAs from water columns in estuarine environments. However, enhancement of sorption of PFAs to particulate matter at high salinity values could evoke potential risks to benthic organisms in estuarine areas.

  16. Influence of organic matter on the transport of Cryptosporidium parvum oocysts in a ferric oxyhydroxide-coated quartz sand saturated porous medium

    USGS Publications Warehouse

    Abudalo, R.A.; Ryan, J.N.; Harvey, R.W.; Metge, D.W.; Landkamer, Lee L.

    2010-01-01

    To assess the effect of organic matter on the transport of Cryptosporidium parvum oocysts in a geochemically heterogeneous saturated porous medium, we measured the breakthrough and collision efficiencies of oocysts as a function of dissolved organic matter concentration in a flow-through column containing ferric oxyhydroxide-coated sand. We characterized the surface properties of the oocysts and ferric oxyhydroxide-coated sand using microelectrophoresis and streaming potential, respectively, and the amount of organic matter adsorbed on the ferric oxyhydroxide-coated sand as a function of the concentration of dissolved organic matter (a fulvic acid isolated from Florida Everglades water). The dissolved organic matter had no significant effect on the zeta potential of the oocysts. Low concentrations of dissolved organic matter were responsible for reversing the charge of the ferric oxyhydroxide-coated sand surface from positive to negative. The charge reversal and accumulation of negative charge on the ferric oxyhydroxide-coated sand led to increases in oocyst breakthrough and decreases in oocyst collision efficiency with increasing dissolved organic matter concentration. The increase in dissolved organic matter concentration from 0 to 20 mg L-1 resulted in a two-fold decrease in the collision efficiency. ?? 2009 Elsevier Ltd.

  17. Organic matter diagenesis as the key to a unifying theory for the genesis of tabular uranium-vanadium deposits in the Morrison Formation, Colorado Plateau

    USGS Publications Warehouse

    Hansley, P.L.; Spirakis, C.S.

    1992-01-01

    Interstitial, epigenetic amorphous organic matter is intimately associated with uranium in the Grants uranium region and is considered essential to genetic models for these deposits. In contrast, uranium minerals are intimately associated with authigenic vanadium chlorite and vanadium oxides in amorphous organic matter-poor ores of the Slick Rock and Henry Mountains mining districts and therefore, in some genetic models amorphous organic matter is not considered crucial to the formation of these deposits. Differences in organic matter content can be explained by recognizing that amorphous organic matter-poor deposits have been subjected to more advanced stages of diagenesis than amorphous organic matter-rich deposits. Evidence that amorphous organic matter was involved in the genesis of organic matter-poor, as well as organic matter-rich, deposits is described. -from Authors

  18. Formation and Stability of Microbially Derived Soil Organic Matter

    NASA Astrophysics Data System (ADS)

    Waldrop, M. P.; Creamer, C.; Foster, A. L.; Lawrence, C. R.; Mcfarland, J. W.; Schulz, M. S.

    2017-12-01

    Soil carbon is vital to soil health, food security, and climate change mitigation, but the underlying mechanisms controlling the stabilization and destabilization of soil carbon are still poorly understood. There has been a conceptual paradigm shift in how soil organic matter is formed which now emphasizes the importance of microbial activity to build stable (i.e. long-lived) and mineral-associated soil organic matter. In this conceptual model, the consumption of plant carbon by microorganisms, followed by subsequent turnover of microbial bodies closely associated with mineral particles, produces a layering of amino acid and lipid residues on the surfaces of soil minerals that remains protected from destabilization by mineral-association and aggregation processes. We tested this new model by examining how isotopically labeled plant and microbial C differ in their fundamental stabilization and destabilization processes on soil minerals through a soil profile. We used a combination of laboratory and field-based approaches to bridge multiple spatial scales, and used soil depth as well as synthetic minerals to create gradients of soil mineralogy. We used Raman microscopy as a tool to probe organic matter association with mineral surfaces, as it allows for the simultaneous quantification and identification of living microbes, carbon, minerals, and isotopes through time. As expected, we found that the type of minerals present had a strong influence on the amount of C retained, but the stabilization of new C critically depends on growth, death, and turnover of microbial cells. Additionally, the destabilization of microbial residue C on mineral surfaces was little affected by flushes of DOC relative to wet-dry cycles alone. We believe this new insight into microbial mechanisms of C stabilization in soils will eventually lead to new avenues for measuring and modeling SOM dynamics in soils, and aid in the management of soil C to mediate global challenges.

  19. CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) SOURCE CHARACTERIZATION IN THE LOUISIANA BIGHT

    EPA Science Inventory

    Chromophoric dissolved organic matter (CDOM) in the Mississippi plume region may have several distinct sources: riverine (terrestrial soils), wetland (terrestrial plants), biological production (phytoplankton, zooplankton, microbial), and sediments. Complex mixing, photodegradati...

  20. Hyperspectral Analysis of Soil Nitrogen, Carbon, Carbonate, and Organic Matter Using Regression Trees

    PubMed Central

    Gmur, Stephan; Vogt, Daniel; Zabowski, Darlene; Moskal, L. Monika

    2012-01-01

    The characterization of soil attributes using hyperspectral sensors has revealed patterns in soil spectra that are known to respond to mineral composition, organic matter, soil moisture and particle size distribution. Soil samples from different soil horizons of replicated soil series from sites located within Washington and Oregon were analyzed with the FieldSpec Spectroradiometer to measure their spectral signatures across the electromagnetic range of 400 to 1,000 nm. Similarity rankings of individual soil samples reveal differences between replicate series as well as samples within the same replicate series. Using classification and regression tree statistical methods, regression trees were fitted to each spectral response using concentrations of nitrogen, carbon, carbonate and organic matter as the response variables. Statistics resulting from fitted trees were: nitrogen R2 0.91 (p < 0.01) at 403, 470, 687, and 846 nm spectral band widths, carbonate R2 0.95 (p < 0.01) at 531 and 898 nm band widths, total carbon R2 0.93 (p < 0.01) at 400, 409, 441 and 907 nm band widths, and organic matter R2 0.98 (p < 0.01) at 300, 400, 441, 832 and 907 nm band widths. Use of the 400 to 1,000 nm electromagnetic range utilizing regression trees provided a powerful, rapid and inexpensive method for assessing nitrogen, carbon, carbonate and organic matter for upper soil horizons in a nondestructive method. PMID:23112620

  1. Search for EPR markers of the history and origin of the insoluble organic matter in extraterrestrial and terrestrial rocks.

    PubMed

    Gourier, Didier; Binet, Laurent; Scrzypczak, Audrey; Derenne, Sylvie; Robert, François

    2004-05-01

    The insoluble organic matter (IOM) of three carbonaceous meteorites (Orgueil, Murchison and Tagish Lake meteorites) and three samples of cherts (microcrystalline SiO2 rock) containing microfossils with age ranging between 45 million years and 3.5 billion years is studied by electron paramagnetic resonance (EPR). The age of the meteorites is that of the solar system (4.6 billion years). The purpose of this work was to determine the EPR parameters, which allow us to discriminate between biogenic and extra terrestrial origin for the organic matter. Such indicators should be relevant for the controversy regarding the biogenicity of the organic matter in the oldest cheroot (3.5 billion years) and in Martian meteorites containing microbe-like microstructures. The organic matter of meteorites contains a high concentration of diradicaloid moieties characterised by a diamagnetic ground state S = 0 and a thermally accessible triplet state S = 1. The three meteorites exhibit the same singlet-triplet gap (ST gap) DeltaE approximately 0.1 eV. To the best of our knowledge, such diradicaloids are unknown in insoluble organic matter of terrestrial origin. We have also shown that the EPR linewidth of insoluble organic matter in cherts and coals decrease logarithmically with the age of the organic matter. We conclude from this result that the organic matter in the oldest cherts (3.5 billion years) has the same age as their SiO2 matrix, and is not due to a latter contamination by bacteria, as was recently found in meteoritic samples.

  2. Spectroscopic characteristics of soil organic matter as a tool to assess soil physical quality in Mediterranean ecosystems

    NASA Astrophysics Data System (ADS)

    Recio Vázquez, Lorena; Almendros, Gonzalo; Knicker, Heike; López-Martín, María; Carral, Pilar; Álvarez, Ana

    2014-05-01

    In Mediterranean areas, the loss of soil physical quality is of particular concern due to the vulnerability of these ecosystems in relation to unfavourable climatic conditions, which usually lead to soil degradation processes and severe decline of its functionality. As a result, increasing scientific attention is being paid on the exploration of soil properties which could be readily used as quality indicators, including organic matter which, in fact, represents a key factor in the maintenance of soil physical status. In this line, the present research tackles the assessment of the quality of several soils from central Spain with the purpose of identifying the physical properties most closely correlated with the organic matter, considering not only the quantity but also the quality of the different C-forms. The studied attributes consist of a series of physical properties determined in field and laboratory conditions-total porosity, aggregate stability, available water capacity, air provision, water infiltration rate and soil hydric saturation-.The bulk organic matter was characterised by solid-state 13C NMR spectroscopy and the major organic fractions (lipids, free particulate organic matter, fulvic acids, humic acids and humin) were quantified using standard procedures. The humic acids were also analysed by visible and infrared spectroscopies. The use of multidimensional scaling to classify physical properties in conjunction with molecular descriptors of soil organic matter, suggested significant correlations between the two set of variables, which were confirmed with simple and canonical regression models. The results pointed to two well-defined groups of physical attributes in the studied soils: (i) those associated with organic matter of predominantly aromatic character (water infiltration descriptors), and (ii) soil physical variables related to organic matter with marked aliphatic character, high preservation of the lignin signature and comparatively low

  3. CO 2 Storage by Sorption on Organic Matter and Clay in Gas Shale

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

    Bacon, Diana H.; Yonkofski, Catherine MR; Schaef, Herbert T.

    2015-10-10

    Simulations of methane production and supercritical carbon dioxide injection were developed that consider competitive adsorption of CH 4 and CO 2 on both organic matter and montmorillonite. The results were used to assess the potential for storage of CO 2 in a hydraulically fractured shale gas reservoir and for enhanced recovery of CH 4. Assuming equal volume fractions of organic matter and montmorillonite, amounts of CO 2 adsorbed on both materials were comparable, while methane desorption was from clays was two times greater than desorption from organic material. The most successful strategy considered CO 2 injection from a separate wellmore » and enhanced methane recovery by 73%, while storing 240 kmt of CO 2.« less

  4. Stability of Soil Organic Matter in Alpine Ecosystems: No Relationship with Vegetation

    NASA Astrophysics Data System (ADS)

    Matteodo, M.; Sebag, D.; Vittoz, P.; Verrecchia, E. P.

    2016-12-01

    There is an emerging understanding of mechanisms governing soil organic matter (SOM) stability, which is challenging the historical view of carbon persistence1. According to this alternative vision, SOM stability is not directly regulated by the molecular structure of plant inputs (i.e. the historical view), but the biotic and abiotic conditions of the surrounding environment which play a major role and mediate the influence of compound chemistry. The persistence of SOM is thus influenced by ecological conditions, controlling the access and activity of decomposers' enzymes and being ecosystem-dependent. In this study, we investigated differences of (1) carbon content, and (2) stability of organic matter in litter and organomineral layers from the most widespread plant communities at the subalpine-alpine level of the Swiss Alps. For this purpose, 230 samples from 47 soil profiles have been analysed across seven plant communities, along a subalpine-alpine elevation gradient. Both calcareous and siliceous grasslands were studied, as well as snowbed and ridge communities. Aboveground litter and A horizons were sampled and analysed using Rock-Eval Pyrolysis, a proxy-technique commonly used for the investigation of organic matter composition and stability2,3. Results show that the litter layers of the seven plant communities are significantly different in terms of total organic carbon (TOC) content, but slightly variable in terms of stability. The situation is radically different in the organomineral horizons where the amount of organic carbon is interestingly homogeneous, as well as the SOM stability. In mineral horizons, the amount and stability of SOM are mainly driven by the geological settings, and therefore vary in the different plant communities. These results show a clear disconnection between organic, organomineral, and mineral horizons in terms of factors governing soil organic matter stability. Consistent with the recent view of the carbon balance, plant input

  5. Occurrence and abundance of carbohydrates and amino compounds in sequentially extracted labile soil organic matter fractions.

    USDA-ARS?s Scientific Manuscript database

    This study aimed to investigate the content of carbohydrates and amino compounds in three labile fraction of soil organic matter (SOM). Soil samples were collected from two agricultural fields in southern Italy and the light fraction (LF), the 500–53-µm particulate organic matter (POM) and the mobil...

  6. Bioavailability and export of dissolved organic matter from a tropical river during base- and stormflow conditions

    Treesearch

    Tracy N. Wiegner; Randee L. Tubal; Richard A. MacKenzie

    2009-01-01

    Concentrations, bioavailability, and export of dissolved organic matter (DOM), particulate organic matter (POM), and nutrients from the Wailuku River, Hawai'i, U.S.A., were examined under base- and stormflow conditions. During storms, DOM and POM concentrations increased approximately by factors of 2 and 11, respectively, whereas NO3...

  7. Impact of natural organic matter on uranium transport through saturated geologic materials: from molecular to column scale.

    PubMed

    Yang, Yu; Saiers, James E; Xu, Na; Minasian, Stefan G; Tyliszczak, Tolek; Kozimor, Stosh A; Shuh, David K; Barnett, Mark O

    2012-06-05

    The risk stemming from human exposure to actinides via the groundwater track has motivated numerous studies on the transport of radionuclides within geologic environments; however, the effects of waterborne organic matter on radionuclide mobility are still poorly understood. In this study, we compared the abilities of three humic acids (HAs) (obtained through sequential extraction of a peat soil) to cotransport hexavalent uranium (U) within water-saturated sand columns. Relative breakthrough concentrations of U measured upon elution of 18 pore volumes increased from undetectable levels (<0.001) in an experiment without HAs to 0.17 to 0.55 in experiments with HAs. The strength of the HA effect on U mobility was positively correlated with the hydrophobicity of organic matter and NMR-detected content of alkyl carbon, which indicates the possible importance of hydrophobic organic matter in facilitating U transport. Carbon and uranium elemental maps collected with a scanning transmission X-ray microscope (STXM) revealed uneven microscale distribution of U. Such molecular- and column-scale data provide evidence for a critical role of hydrophobic organic matter in the association and cotransport of U by HAs. Therefore, evaluations of radionuclide transport within subsurface environments should consider the chemical characteristics of waterborne organic substances, especially hydrophobic organic matter.

  8. Disturbance of Soil Organic Matter and Nitrogen Dynamics: Implications for Soil and Water Quality

    DTIC Science & Technology

    2004-06-30

    Although we were unable to provide a precise chemical analysis of refractory soil carbon, it does appear to have the same chemical properties as... chemical analysis of this refractory carbon, but it has chemical properties similar to charcoal (Garten et al., 2003) and probably originates from...vegetation and forests at Fort Benning includes ≈10% refractory C that is chemically similar to charcoal (Garten and Ashwood, 2004) and probably has

  9. Effect of concentration of dispersed organic matter on optical maturity parameters: Interlaboratory results of the organic matter concentration working group of the ICCP.

    USGS Publications Warehouse

    Mendonca, Filho J.G.; Araujo, C.V.; Borrego, A.G.; Cook, A.; Flores, D.; Hackley, P.; Hower, J.C.; Kern, M.L.; Kommeren, K.; Kus, J.; Mastalerz, Maria; Mendonca, J.O.; Menezes, T.R.; Newman, J.; Ranasinghe, P.; Souza, I.V.A.F.; Suarez-Ruiz, I.; Ujiie, Y.

    2010-01-01

    The main objective of this work was to study the effect of the kerogen isolation procedures on maturity parameters of organic matter using optical microscopes. This work represents the results of the Organic Matter Concentration Working Group (OMCWG) of the International Committee for Coal and Organic Petrology (ICCP) during the years 2008 and 2009. Four samples have been analysed covering a range of maturity (low and moderate) and terrestrial and marine geological settings. The analyses comprise random vitrinite reflectance measured on both kerogen concentrate and whole rock mounts and fluorescence spectra taken on alginite. Eighteen participants from twelve laboratories from all over the world performed the analyses. Samples of continental settings contained enough vitrinite for participants to record around 50 measurements whereas fewer readings were taken on samples from marine setting. The scatter of results was also larger in the samples of marine origin. Similar vitrinite reflectance values were in general recorded in the whole rock and in the kerogen concentrate. The small deviations of the trend cannot be attributed to the acid treatment involved in kerogen isolation but to reasons related to components identification or to the difficulty to achieve a good polish of samples with high mineral matter content. In samples difficult to polish, vitrinite reflectance was measured on whole rock tended to be lower. The presence or absence of rock fabric affected the selection of the vitrinite population for measurement and this also had an influence in the average value reported and in the scatter of the results. Slightly lower standard deviations were reported for the analyses run on kerogen concentrates. Considering the spectral fluorescence results, it was observed that the ??max presents a shift to higher wavelengths in the kerogen concentrate sample in comparison to the whole-rock sample, thus revealing an influence of preparation methods (acid treatment) on

  10. Nitrogen removal capacity and bacterial community dynamics of a Canon biofilter system at different organic matter concentrations.

    PubMed

    García-Ruiz, María J; Maza-Márquez, Paula; González-López, Jesús; Osorio, Francisco

    2018-02-01

    Three Canon bench-scale bioreactors with a volume of 2 L operating in parallel were configured as submerged biofilters. In the present study we investigated the effects of a high ammonium concentration (320 mgNH 4 + · L -1 ) and different concentrations of organic matter (0, 100 and 400 mgCOD·L -1 ) on the nitrogen removal capacity and the bacterial community structure. After 60 days, the Canon biofilters operated properly under concentrations of 0 and 100 mgCOD·L -1 of organic matter, with nitrogen removal efficiencies up to 85%. However, a higher concentration of organic matter (400 mgCOD·L -1 ) produced a partial inhibition of nitrogen removal (68.1% efficiency). The addition of higher concentrations of organic matter a modified the bacterial community structure in the Canon biofilter, increasing the proliferation of heterotrophic bacteria related to the genera of Thauera, Longilinea, Ornatilinea, Thermomarinilinea, unclassified Chlorobiales and Denitratisoma. However, heterotrophic bacteria co-exist with Nitrosomonas and Candidatus Scalindua. Thus, our study confirms the co-existence of different microbial activities (AOB, Anammox and denitrification) and the adaptation of a fixed-biofilm system to different concentrations of organic matter. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Biodegradability of organic matter associated with sewer sediments during first flush.

    PubMed

    Sakrabani, Ruben; Vollertsen, Jes; Ashley, Richard M; Hvitved-Jacobsen, Thorkild

    2009-04-01

    The high pollution load in wastewater at the beginning of a rain event is commonly known to originate from the erosion of sewer sediments due to the increased flow rate under storm weather conditions. It is essential to characterize the biodegradability of organic matter during a storm event in order to quantify the effect it can have further downstream to the receiving water via discharges from Combined Sewer Overflow (CSO). The approach is to characterize the pollutograph during first flush. The pollutograph shows the variation in COD and TSS during a first flush event. These parameters measure the quantity of organic matter present. However these parameters do not indicate detailed information on the biodegradability of the organic matter. Such detailed knowledge can be obtained by dividing the total COD into fractions with different microbial properties. To do so oxygen uptake rate (OUR) measurements on batches of wastewater have shown itself to be a versatile technique. Together with a conceptual understanding of the microbial transformation taking place, OUR measurements lead to the desired fractionation of the COD. OUR results indicated that the highest biodegradability is associated with the initial part of a storm event. The information on physical and biological processes in the sewer can be used to better manage sediment in sewers which can otherwise result in depletion of dissolved oxygen in receiving waters via discharges from CSOs.

  12. Organic matter from the Bunte Breccia of the Ries Crater, southern Germany: investigating possible thermal effects of the impact

    NASA Astrophysics Data System (ADS)

    Hofmann, P.; Leythaeuser, D.; Schwark, L.

    2001-07-01

    In order to determine thermal effects of the Ries impact, southern Germany, on organic matter in its ejecta blanket, the maturity of organic matter of Posidonia Shale components from the Bunte Breccia at Harburg and Gundelsheim is compared with the maturity of organic matter of a reference section of Posidonia Shale outside the impact site at Hesselberg. Three black shale samples from the Bunte Breccia were identified as corresponding to the organic matter-rich Posidonia Shale based on the molecular composition of extractable organic matter. They show n-alkane patterns with a maximum of n-C 17, a predominance of odd over even n-alkanes in the range from n-C 26 to n-C 35, a dominance of unsaturated sterenes over steranes and monoaromatic over triaromatic steroids, and contain isorenieratene. The maturity of the organic matter from the Bunte Breccia samples corresponds to 0.32-0.35% random vitrinite reflectance ( Rr) and a spectral red/green quotient ( Q) of 0.32-0.34. The organic matter from the Bunte Breccia is more mature than the Posidonia Shale sample from the reference site Hesselberg (0.25% Rr; 0.21 for Q). The thermal overprint is presumed to be too high to be explained by differences in the burial history prior to the impact alone and is, therefore, attributed to processes related to the displacement of the Bunte Breccia.

  13. Preservation of organic matter in marine sediments by inner-sphere interactions with reactive iron

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

    Barber, Andrew; Brandes, Jay; Leri, Alessandra

    Interactions between organic matter and mineral matrices are critical to the preservation of soil and sediment organic matter. In addition to clay minerals, Fe(III) oxides particles have recently been shown to be responsible for the protection and burial of a large fraction of sedimentary organic carbon (OC). Through a combination of synchrotron X-ray techniques and high-resolution images of intact sediment particles, we assessed the mechanism of interaction between OC and iron, as well as the composition of organic matter co-localized with ferric iron. We present scanning transmission x-ray microscopy images at the Fe L 3 and C K1 edges showingmore » that the organic matter co-localized with Fe(III) consists primarily of C=C, C=O and C-OH functional groups. Coupling the co-localization results to iron K-edge X-ray absorption spectroscopy fitting results allowed to quantify the relative contribution of OC-complexed Fe to the total sediment iron and reactive iron pools, showing that 25–62% of total reactive iron is directly associated to OC through inner-sphere complexation in coastal sediments, as much as four times more than in low OC deep sea sediments. Direct inner-sphere complexation between OC and iron oxides (Fe-O-C) is responsible for transferring a large quantity of reduced OC to the sedimentary sink, which could otherwise be oxidized back to CO 2.« less

  14. Applications of Fluorescence Spectroscopy for dissolved organic matter characterization in wastewater treatment plants

    NASA Astrophysics Data System (ADS)

    Goffin, Angélique; Guérin, Sabrina; Rocher, Vincent; Varrault, Gilles

    2016-04-01

    Dissolved organic matter (DOM) influences wastewater treatment plants efficiency (WTTP): variations in its quality and quantity can induce a foaming phenomenon and a fouling event inside biofiltration processes. Moreover, in order to manage denitrification step (control and optimization of the nitrate recirculation), it is important to be able to estimate biodegradable organic matter quantity before biological treatment. But the current methods used to characterize organic matter quality, like biological oxygen demand are laborious, time consuming and sometimes not applicable to directly monitor organic matter in situ. In the context of MOCOPEE research program (www.mocopee.com), this study aims to assess the use of optical techniques, such as UV-Visible absorbance and more specifically fluorescence spectroscopy in order to monitor and to optimize process efficiency in WWTP. Fluorescence excitation-emission matrix (EEM) spectroscopy was employed to prospect the possibility of using this technology online and in real time to characterize dissolved organic matter in different effluents of the WWTP Seine Centre (240,000 m3/day) in Paris, France. 35 sewage water influent samples were collected on 10 days at different hours. Data treatment were performed by two methods: peak picking and parallel factor analysis (PARAFAC). An evolution of DOM quality (position of excitation - emission peaks) and quantity (intensity of fluorescence) was observed between the different treatment steps (influent, primary treatment, biological treatment, effluent). Correlations were found between fluorescence indicators and different water quality key parameters in the sewage influents. We developed different multivariate linear regression models in order to predict a variety of water quality parameters by fluorescence intensity at specific excitation-emission wavelengths. For example dissolved biological oxygen demand (r2=0,900; p<0,0001) and ammonium concentration (r2=0,898; p<0

  15. Soil organic matter as sole indicator of soil degradation

    Treesearch

    S.E. Obalum; G.U. Chibuike; S. Peth; Ying Ouyang

    2017-01-01

    Soil organic matter (SOM) is known to play vital roles in the maintenance and improvement of many soil properties and processes. These roles, which largely influence soil functions, are a pool of specific contributions of different components of SOM. The soil functions, in turn, normally define the level of soil degradation, viewed as quantifiable temporal changes in a...

  16. Predicting Chromophoric Dissolved Organic Matter Distributions in Coastal Waters

    DTIC Science & Technology

    2006-01-01

    Predicting Chromophoric Dissolved Organic Matter Distributions in Coastal Waters Robert F. Chen Environmental , Earth and Ocean Sciences...G. Bernard Gardner Environmental , Coastal and Ocean Sciences University of Massachusetts Boston 100 Morrissey Boulevard Boston, MA 02125-3393...phone: (617)287-7451 fax: (617)287-7474 email: bernie.gardner@umb.edu Yong Tian Environmental , Coastal and Ocean Sciences University of

  17. Predicting Chromophoric Dissolved Organic Matter Distributions in Coastal Waters

    DTIC Science & Technology

    2007-09-30

    Predicting Chromophoric Dissolved Organic Matter Distributions in Coastal Waters Robert F. Chen Environmental , Earth and Ocean Sciences...G. Bernard Gardner Environmental , Coastal and Ocean Sciences University of Massachusetts Boston 100 Morrissey Boulevard Boston, MA 02125-3393...phone: (617)287-7451 fax: (617)287-7474 email: bernie.gardner@umb.edu Yong Tian Environmental , Coastal and Ocean Sciences University of

  18. Predicting Chromophoric Dissolved Organic Matter Distributions in Coastal Waters

    DTIC Science & Technology

    2008-09-30

    Predicting Chromophoric Dissolved Organic Matter Distributions in Coastal Waters Robert F. Chen Environmental , Earth and Ocean...umb.edu G. Bernard Gardner Environmental , Coastal and Ocean Sciences University of Massachusetts Boston 100 Morrissey Boulevard Boston, MA...02125-3393 phone: (617) 287-7451 fax: (617) 287-7474 email: bernie.gardner@umb.edu Yong Tian Environmental , Coastal and Ocean Sciences

  19. Refractory Pain Management in Amyloid-Associated Peripheral Neuropathy.

    PubMed

    Warner, Nafisseh S; Watson, James C; Bendel, Markus A; Moeschler, Susan M

    2018-05-01

    Systemic amyloidosis is a disease that often involves multiple organ systems, including the peripheral nervous system. Patients may present with severe, refractory neuropathic pain; however, the optimal treatment approach for pain for these patients remains unclear. A man with severe, refractory neuropathic pain in his bilateral upper and lower extremities and the trunk secondary to amyloid neuropathy is presented. Multiple medication trials, including neuropathic and opioid agents, produced considerable adverse effects and minimal relief. Scrambler therapy, a novel electrical stimulation modality, was used and was associated with substantial short-term but nonsustained benefit. Spinal cord stimulation was considered, but given his diffuse symptoms, it was deemed a less-than-optimal approach. Ultimately, an intrathecal drug delivery system was placed with infusion of hydromorphone, resulting in substantial pain reduction in all involved areas and with an improved adverse effect profile. This intervention resulted in immense improvement in the patient's quality of life, despite progression of his systemic amyloidosis. Severe pain in the setting of amyloid neuropathy is often difficult to treat. To our knowledge, this represents the first report of Scrambler therapy or an implanted intrathecal drug delivery system used for a patient with refractory amyloidosis-related neuropathic pain, resulting in substantial analgesic benefit and improved quality of life.

  20. Evidence of micropore filling for sorption of nonpolar organic contaminants by condensed organic matter.

    PubMed

    Ran, Yong; Yang, Yu; Xing, Baoshan; Pignatello, Joseph J; Kwon, Seokjoo; Su, Wei; Zhou, Li

    2013-01-01

    Although microporosity and surface area of natural organic matter (NOM) are crucial for mechanistic evaluation of the sorption process for nonpolar organic contaminants (NOCs), they have been underestimated by the N adsorption technique. We investigated the CO-derived internal hydrophobic microporosity () and specific surface area (SSA) obtained on dry samples and related them to sorption behaviors of NOCs in water for a wide range of condensed NOM samples. The is obtained from the total CO-derived microporosity by subtracting out the contribution of the outer surfaces of minerals and NOM using N adsorption-derived parameters. The correlation between or CO-SSA and fractional organic carbon content () is very significant, demonstrating that much of the microporosity is associated with internal NOM matrices. The average and CO-SSA are, respectively, 75.1 μL g organic carbon (OC) and 185 m g OC from the correlation analysis. The rigid aliphatic carbon significantly contributes to the microporosity of the Pahokee peat. A strong linear correlation is demonstrated between / and the OC-normalized sorption capacity at the liquid or subcooled liquid-state water solubility calculated via the Freundlich equation for each of four NOCs (phenanthrene, naphthalene, 1,3,5-trichlorobenzene, and 1,2-dichlorobenzene). We concluded that micropore filling ("adsorption") contributes to NOC sorption by condensed NOM, but the exact contribution requires knowing the relationship between the dry-state, CO-determined microporosity and the wet-state, NOC-available microporosity of the organic matter. The findings offer new clues for explaining the nonideal sorption behaviors of NOCs. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  1. PHOTOREACTIVITY OF CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) DERIVED FROM DECOMPOSITION OF VARIOUS VASCULAR PLANT AND ALGAL SOURCES

    EPA Science Inventory

    Chromophoric dissolved organic matter (CDOM) in aquatic environments is derived from the microbial decomposition of terrestrial and microbial organic matter. Here we present results of studies of the spectral properties and photoreactivity of the CDOM derived from several organi...

  2. Talimogene Laherparepvec and Nivolumab in Treating Patients With Refractory Lymphomas or Advanced or Refractory Non-melanoma Skin Cancers

    ClinicalTrials.gov

    2018-06-25

    Adenoid Cystic Carcinoma; Adnexal Carcinoma; Apocrine Carcinoma; Eccrine Porocarcinoma; Extraocular Cutaneous Sebaceous Carcinoma; Hidradenocarcinoma; Keratoacanthoma; Malignant Sweat Gland Neoplasm; Merkel Cell Carcinoma; Microcystic Adnexal Carcinoma; NK-Cell Lymphoma, Unclassifiable; Non-Melanomatous Lesion; Paget Disease; Papillary Adenocarcinoma; Primary Cutaneous Mucinous Carcinoma; Refractory Anaplastic Large Cell Lymphoma; Refractory Mature T-Cell and NK-Cell Non-Hodgkin Lymphoma; Refractory Mycosis Fungoides; Refractory Primary Cutaneous T-Cell Non-Hodgkin Lymphoma; Refractory T-Cell Non-Hodgkin Lymphoma; Sezary Syndrome; Signet Ring Cell Carcinoma; Skin Basal Cell Carcinoma; Skin Basosquamous Cell Carcinoma; Skin Squamous Cell Carcinoma; Spiradenocarcinoma; Squamous Cell Carcinoma of Unknown Primary Origin; Stage III Skin Cancer; Stage IV Skin Cancer; Sweat Gland Carcinoma; Trichilemmocarcinoma; Vulvar Squamous Cell Carcinoma

  3. Macroinvertebrate and organic matter export from headwater tributaries of a Central Appalachian stream

    EPA Science Inventory

    Headwater streams export organisms and other materials to their receiving streams and macroinvertebrate drift can shape colonization dynamics in downstream reaches while providing food for downstream consumers. Spring-time macroinvertebrate drift and organic matter export was me...

  4. One-pot synthesis of amino acid precursors with insoluble organic matter in planetesimals with aqueous activity.

    PubMed

    Kebukawa, Yoko; Chan, Queenie H S; Tachibana, Shogo; Kobayashi, Kensei; Zolensky, Michael E

    2017-03-01

    The exogenous delivery of organic molecules could have played an important role in the emergence of life on the early Earth. Carbonaceous chondrites are known to contain indigenous amino acids as well as various organic compounds and complex macromolecular materials, such as the so-called insoluble organic matter (IOM), but the origins of the organic matter are still subject to debate. We report that the water-soluble amino acid precursors are synthesized from formaldehyde, glycolaldehyde, and ammonia with the presence of liquid water, simultaneously with macromolecular organic solids similar to the chondritic IOM. Amino acid products from hydrothermal experiments after acid hydrolysis include α-, β-, and γ-amino acids up to five carbons, for which relative abundances are similar to those extracted from carbonaceous chondrites. One-pot aqueous processing from simple ubiquitous molecules can thus produce a wide variety of meteoritic organic matter from amino acid precursors to macromolecular IOM in chondrite parent bodies.

  5. NITROGEN DEPOSITION AND ORGANIC MATTER MANIPULATIONS AFFECT GROSS AND NET NITROGEN TRANSFORMATIONS IN TWO TEMPERATE FORESTS SOILS

    EPA Science Inventory

    Soil nitrogen transformations are intricately linked to carbon transformations. We utilized two existing organic matter manipulation sites in western Oregon, USA and Hungary to investigate these linkages. Our questions were: 1) Does the quantity and quality of organic matter af...

  6. Dissolved Organic Matter (DOM) Export from Watersheds to Coastal Oceans

    NASA Astrophysics Data System (ADS)

    Chen, R. F.; Gardner, G. B.; Peri, F.

    2016-02-01

    Dissolved organic matter (DOM) from terrestrial plants and soils is transported by surface waters and groundwaters to coastal ocean waters. Along the way, photochemical and biological degradation can remove DOM, and in situ processes such as phytoplankton leaching and sediment sources can add to the DOM in the river water. Wetlands, especially coastal wetlands can add significant amounts of DOM that is carried by rivers and is exported through estuaries to coastal systems. We will present observational data from a variety of coastal systems (San Francisco Bay, Boston Harbor, Chesapeake Bay, Hudson River, the Mississippi River, and a small salt marsh in the Gulf of Mexico). High resolution measurements of chromophoric dissolved organic matter (CDOM) can be correlated with dissolved organic carbon (DOC) so can be used to estimate DOC in specific systems and seasons. Gradients in CDOM/DOC combined with water fluxes can be used to estimate DOC fluxes from a variety of coastal watersheds to coastal systems. Influences of land use, system size, residence time, DOM quality, and photochemical and biological degradation will be discussed. The significance of coastal wetlands in the land-to-ocean export of DOC will be emphasized.

  7. cyclostratigraphy, sequence stratigraphy and organic matter accumulation mechanism

    NASA Astrophysics Data System (ADS)

    Cong, F.; Li, J.

    2016-12-01

    The first member of Maokou Formation of Sichuan basin is composed of well preserved carbonate ramp couplets of limestone and marlstone/shale. It acts as one of the potential shale gas source rock, and is suitable for time-series analysis. We conducted time-series analysis to identify high-frequency sequences, reconstruct high-resolution sedimentation rate, estimate detailed primary productivity for the first time in the study intervals and discuss organic matter accumulation mechanism of source rock under sequence stratigraphic framework.Using the theory of cyclostratigraphy and sequence stratigraphy, the high-frequency sequences of one outcrop profile and one drilling well are identified. Two third-order sequences and eight fourth-order sequences are distinguished on outcrop profile based on the cycle stacking patterns. For drilling well, sequence boundary and four system tracts is distinguished by "integrated prediction error filter analysis" (INPEFA) of Gamma-ray logging data, and eight fourth-order sequences is identified by 405ka long eccentricity curve in depth domain which is quantified and filtered by integrated analysis of MTM spectral analysis, evolutive harmonic analysis (EHA), evolutive average spectral misfit (eASM) and band-pass filtering. It suggests that high-frequency sequences correlate well with Milankovitch orbital signals recorded in sediments, and it is applicable to use cyclostratigraphy theory in dividing high-frequency(4-6 orders) sequence stratigraphy.High-resolution sedimentation rate is reconstructed through the study interval by tracking the highly statistically significant short eccentricity component (123ka) revealed by EHA. Based on sedimentation rate, measured TOC and density data, the burial flux, delivery flux and primary productivity of organic carbon was estimated. By integrating redox proxies, we can discuss the controls on organic matter accumulation by primary production and preservation under the high-resolution sequence

  8. Carbon Characteristics and Biogeochemical Processes of Uranium Accumulating Organic Matter Rich Sediments in the Upper Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Boye, K.; Noel, V.; Tfaily, M. M.; Dam, W. L.; Bargar, J.; Fendorf, S. E.

    2015-12-01

    Uranium plume persistence in groundwater aquifers is a problem on several former ore processing sites on floodplains in the upper Colorado River Basin. Earlier observations by our group and others at the Old Rifle Site, CO, have noted that U concentrations are highest in organic rich, fine-grained, and, therefore, diffusion limited sediment material. Due to the constantly evolving depositional environments of floodplains, surficial organic matter may become buried at various stages of decomposition, through sudden events such as overbank flooding and through the slower progression of river meandering. This creates a discontinuous subsurface distribution of organic-rich sediments, which are hotspots for microbial activity and thereby central to the subsurface cycling of contaminants (e.g. U) and biologically relevant elements (e.g. C, N, P, Fe). However, the organic matter itself is poorly characterized. Consequently, little is known about its relevance in driving biogeochemical processes that control U fate and transport in the subsurface. In an investigation of soil/sediment cores from five former uranium ore processing sites on floodplains distributed across the Upper Colorado River Basin we confirmed consistent co-enrichment of U with organic-rich layers in all profiles. However, using C K-edge X-ray Absorption Spectroscopy (XAS) coupled with Fourier-Transformed Ion-Cyclotron-Resonance Mass-Spectroscopy (FT-ICR-MS) on bulk sediments and density-separated organic matter fractions, we did not detect any chemical difference in the organic rich sediments compared to the surrounding coarser-grained aquifer material within the same profile, even though there were differences in organic matter composition between the 5 sites. This suggests that U retention and reduction to U(IV) is independent of C chemical composition on the bulk scale. Instead it appears to be the abundance of organic matter in combination with a limited O2 supply in the fine-grained material that

  9. Sources and Distribution of Organic Matter in Sediments of the Louisiana Continental Shelf

    EPA Science Inventory

    Both riverine and marine sources of organic matter (OM) contribute to sediment organic pools, and either source can contribute significantly to sediment accumulation, burial, and remineralization rates on river dominated continental shelf systems. For the Louisiana continental sh...

  10. Clinical features and course of refractory anemia with ring sideroblasts associated with marked thrombocytosis

    PubMed Central

    Broseus, Julien; Florensa, Lourdes; Zipperer, Esther; Schnittger, Susanne; Malcovati, Luca; Richebourg, Steven; Lippert, Eric; Cermak, Jaroslav; Evans, Jyoti; Mounier, Morgane; Raya, José Maria; Bailly, François; Gattermann, Norbert; Haferlach, Torsten; Garand, Richard; Allou, Kaoutar; Besses, Carlos; Germing, Ulrich; Haferlach, Claudia; Travaglino, Erica; Luno, Elisa; Pinan, Maria Angeles; Arenillas, Leonor; Rozman, Maria; Perez Sirvent, Maria Luz; Favre, Bernardine; Guy, Julien; Alonso, Esther; Ahwij, Nuhri; Jerez, Andrés; Hermouet, Sylvie; Maynadié, Marc; Cazzola, Mario; Girodon, François

    2012-01-01

    Background Refractory anemia with ring sideroblasts associated with marked thrombocytosis was proposed as a provisional entity in the 2001 World Health Organization classification of myeloid neoplasms and also in the 2008 version, but its existence as a single entity is contested. We wish to define the clinical features of this rare myelodysplastic/myeloproliferative neoplasm and to compare its clinical outcome with that of refractory anemia with ring sideroblasts and essential thrombocythemia. Design and Methods We conducted a collaborative retrospective study across Europe. Our database included 200 patients diagnosed with refractory anemia with ring sideroblasts and marked thrombocytosis. For each of these patients, each patient diagnosed with refractory anemia with ring sideroblasts was matched for age and sex. At the same time, a cohort of 454 patients with essential thrombocythemia was used to compare outcomes of the two diseases. Results In patients with refractory anemia with ring sideroblasts and marked thrombocytosis, depending on the Janus Kinase 2 V617F mutational status (positive or negative) or platelet threshold (over or below 600×109/L), no difference in survival was noted. However, these patients had shorter overall survival and leukemia-free survival with a lower risk of thrombotic complications than did patients with essential thrombocythemia (P<0.001) but better survival (P<0.001) and a higher risk of thrombosis (P=0.039) than patients with refractory anemia with ring sideroblasts. Conclusions The clinical course of refractory anemia with ring sideroblasts and marked thrombocytosis is better than that of refractory anemia with ring sideroblasts and worse than that of essential thrombocythemia. The higher risk of thrombotic events in this disorder suggests that anti-platelet therapy might be considered in this subset of patients. From a clinical point of view, it appears to be important to consider refractory anemia with ring sideroblasts and

  11. Nitrogen removal performance of anaerobic ammonia oxidation (ANAMMOX) in presence of organic matter.

    PubMed

    Zhu, Weiqiang; Zhang, Peiyu; Yu, Deshuang; Dong, Huiyu; Li, Jin

    2017-06-01

    A sequencing batch reactor (SBR) was used to test the nitrogen removal performance of anaerobic ammonium oxidation (ANAMMOX) in presence of organic matter. Mesophilic operation (30 ± 0.5 °C) was performed with influent pH 7.5. The results showed, independent of organic matter species, ANAMMOX reaction was promoted when COD was lower than 80 mg/L. However, specific ANAMMOX activity decreased with increasing organic matter content. Ammonium removal efficiency decreased to 80% when COD of sodium succinate, sodium potassium tartrate, peptone and lactose were 192.5, 210, 225 and 325 mg/L, respectively. The stoichiometry ratio resulting from different OM differed largely and R 1 could be as an indicator for OM inhibition. When COD concentration was 240 mg/L, the loss of SAA resulting from lactose, peptone, sodium potassium tartrate and sodium succinate were 28, 36, 50 and 55%, respectively. Sodium succinate had the highest inhibitory effect on SAA. When ANAMMOX process was used to treat wastewater containing OM, the modified Logistic model could be employed to predict the NRE max .

  12. Sorption of vapors of some organic liquids on soil humic acid and its relation to partitioning of organic compounds in soil organic matter

    USGS Publications Warehouse

    Chlou, G.T.; Kile, D.E.; Malcolm, R.L.

    1988-01-01

    Vapor sorption of water, ethanol, benzene, hexane, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and 1,2-dibromoethane on (Sanhedron) soil humic acid has been determined at room temperature. Isotherms for all organic liquids are highly linear over a wide range of relative pressure (P/P??), characteristic of the partitioning (dissolution) of the organic compounds in soil humic acid. Polar liquids exhibit markedly greater sorption capacities on soil humic acid than relatively nonpolar liquids, in keeping with the polar nature of the soil humic acid as a partition medium. The limiting sorption (partition) capacities of relatively non-polar liquids are remarkably similar when expressed in terms of volumes per unit weight of soil humic acid. The soil humic acid is found to be about half as effective as soil organic matter in sorption of relatively nonpolar organic compounds. The nearly constant limiting sorption capacity for nonpolar organic liquids with soil humic acid on a volume-to-weight basis and its efficiency in sorption relative to soil organic matter provide a basis for predicting the approximate sorption (partition) coefficients of similar compounds in uptake by soil in aqueous systems.

  13. Increased nitrogen availability counteracts climatic change feedback from increased temperature on boreal forest soil organic matter degradation

    NASA Astrophysics Data System (ADS)

    Erhagen, Bjorn; Nilsson, Mats; Oquist, Mats; Ilstedt, Ulrik; Sparrman, Tobias; Schleucher, Jurgen

    2014-05-01

    Over the last century, the greenhouse gas concentrations in the atmosphere have increased dramatically, greatly exceeding pre-industrial levels that had prevailed for the preceding 420 000 years. At the same time the annual anthropogenic contribution to the global terrestrial nitrogen cycle has increased and currently exceeds natural inputs. Both temperature and nitrogen levels have profound effects on the global carbon cycle including the rate of organic matter decomposition, which is the most important biogeochemical process that returns CO2 to the atmosphere. Here we show for the first time that increasing the availability of nitrogen not only directly affects the rate of organic matter decomposition but also significantly affects its temperature dependence. We incubated litter and soil organic matter from a long-term (40 years) nitrogen fertilization experiment in a boreal Scots pine (Pinus silvestris L.) forest at different temperatures and determined the temperature dependence of the decomposition of the sample's organic matter in each case. Nitrogen fertilization did not affect the temperature sensitivity (Q10) of the decomposition of fresh plant litter but strongly reduced that for humus soil organic matter. The Q10 response of the 0-3 cm soil layer decreased from 2.5±0.35 to an average of 1.9±0.21 over all nitrogen treatments, and from 2.2±0.19 to 1.6±0.16 in response to the most intense nitrogen fertilization treatment in the 4-7 cm soil layer. Long-term nitrogen additions also significantly affected the organic chemical composition (as determined by 13C CP-MAS NMR spectroscopy) of the soil organic matter. These changes in chemical composition contributed significantly (p<0.05) to the reduced Q10 response. These new insights into the relationship between nitrogen availability and the temperature sensitivity of organic matter decomposition will be important for understanding and predicting how increases in global temperature and rising anthropogenic

  14. Testing Requirements for Refractory Materials

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark R.; Sampson, Jeffrey W.; Montgomery, Eliza M.

    2011-01-01

    Launch Pads 39A and 39B currently use refractory material (Fondu Fyre) in the flame trenches. This material was initially approved for the Saturn program. This material had a lifetime of 10 years according to the manufacturer, and it has been used for over 40 years. As a consequence, the Fondu Fyre at Launch Complex 39 requires repair subsequent to almost every launch. A review of the literature indicates that the gunned Fondu Fyre refractory product (WA-1G) was never tested prior to use. With the recent severe damage to the flame trenches, a new refractory material is sought to replace Fondu Fyre. In order to replace Fondu Fyre, a methodology to test and evaluate refractory products was developed. This paper outlines this methodology and discusses current testing requirements, as well as the laboratory testing that might be required. Furthermore, this report points out the necessity for subscale testing, the locations where this testing can be performed, and the parameters that will be necessary to qualify a product. The goal is to identify a more durable refractory material that has physical, chemical, and thermal properties suitable to withstand the harsh environment of the launch pads at KSC.

  15. Testing Requirements for Refractory Materials

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark R.; Sampson, Jeffrey W.; Montgomery, Eliza M.

    2010-01-01

    Launch Pads 39A and 39B currently use refractory material (Fondu Fyre) in the flame trenches. This material was initially approved for the Saturn program. This material had a lifetime of 10 years according to the manufacturer, and it has been used for over 40 years. As a consequence, the Fondu Fyre at Launch Complex 39 requires repair subsequent to almost every launch. A review of the literature indicates that the gunned Fondu Fyre refractory product (WA-1G) was never tested prior to use. With the recent severe damage to the flame trenches, a new refractory material is sought to replace Fondu Fyre. In order to replace Fondu Fyre, a methodology to test and evaluate refractory products was developed. This paper outlines this methodology and discusses current testing requirements, as well as the laboratory testing that might be required. Furthermore, this report points out the necessity for subscale testing, the locations where this testing can be performed, and the parameters that will be necessary to qualify a product. The goal is to identify a more durable refractory material that has physical, chemical, and thermal properties suitable to withstand the harsh environment of the launch pads at KSC.

  16. Testing Requirements for Refractory Materials

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark R.; Sampson, Jeffrey W,; Montgomery, Eliza M.

    2012-01-01

    Launch Pads 39A and 39B currently use refractory material (Fondu Fyre) in the flame trenches. This material was initially approved for the Saturn program. This material had a lifetime of 10years according to the manufacturer, and it has been used for over 40 years. As a consequence, the Fondu Fyre at Launch Complex 39 requires repair subsequent to almost every launch. A review of the literature indicates that the gunned Fondu Fyre refractory product (WA-1 G) was never tested prior to use. With the recent severe damage to the flame trenches, a new refractory material is sought to replace Fondu Fyre. In order to replace Fondu Fyre, a methodology to test and evaluate refractory products was developed. This paper outlines this methodology and discusses current testing requirements, as well as the laboratory testing that might be required. Furthermore, this report points out the necessity for subscale testing, the locations where this testing can be performed, and the parameters that will be necessary to qualify a product. The goal is to identify a more durable refractory material that has physical, chemical, and thermal properties suitable to withstand the harsh environment of the launch pads at KSC.

  17. Development of online automatic detector of hydrocarbons and suspended organic matter by simultaneously acquisition of fluorescence and scattering.

    PubMed

    Mbaye, Moussa; Diaw, Pape Abdoulaye; Gaye-Saye, Diabou; Le Jeune, Bernard; Cavalin, Goulven; Denis, Lydie; Aaron, Jean-Jacques; Delmas, Roger; Giamarchi, Philippe

    2018-03-05

    Permanent online monitoring of water supply pollution by hydrocarbons is needed for various industrial plants, to serve as an alert when thresholds are exceeded. Fluorescence spectroscopy is a suitable technique for this purpose due to its sensitivity and moderate cost. However, fluorescence measurements can be disturbed by the presence of suspended organic matter, which induces beam scattering and absorption, leading to an underestimation of hydrocarbon content. To overcome this problem, we propose an original technique of fluorescence spectra correction, based on a measure of the excitation beam scattering caused by suspended organic matter on the left side of the Rayleigh scattering spectral line. This correction allowed us to obtain a statistically validated estimate of the naphthalene content (used as representative of the polyaromatic hydrocarbon contamination), regardless of the amount of suspended organic matter in the sample. Moreover, it thus becomes possible, based on this correction, to estimate the amount of suspended organic matter. By this approach, the online warning system remains operational even when suspended organic matter is present in the water supply. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Changes in functional organization and white matter integrity in the connectome in Parkinson's disease.

    PubMed

    Tinaz, Sule; Lauro, Peter M; Ghosh, Pritha; Lungu, Codrin; Horovitz, Silvina G

    2017-01-01

    Parkinson's disease (PD) leads to dysfunction in multiple cortico-striatal circuits. The neurodegeneration has also been associated with impaired white matter integrity. This structural and functional "disconnection" in PD needs further characterization. We investigated the structural and functional organization of the PD whole brain connectome consisting of 200 nodes using diffusion tensor imaging and resting-state functional MRI, respectively. Data from 20 non-demented PD patients on dopaminergic medication and 20 matched controls were analyzed using graph theory-based methods. We focused on node strength, clustering coefficient, and local efficiency as measures of local network properties; and network modularity as a measure of information flow. PD patients showed reduced white matter connectivity in frontoparietal-striatal nodes compared to controls, but no change in modular organization of the white matter tracts. PD group also showed reduction in functional local network metrics in many nodes distributed across the connectome. There was also decreased functional modularity in the core cognitive networks including the default mode and dorsal attention networks, and sensorimotor network, as well as a lack of modular distinction in the orbitofrontal and basal ganglia nodes in the PD group compared to controls. Our results suggest that despite subtle white matter connectivity changes, the overall structural organization of the PD connectome remains robust at relatively early disease stages. However, there is a breakdown in the functional modular organization of the PD connectome.

  19. Carbon, hydrogen and nitrogen isotopes in solvent-extractable organic matter from carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Epstein, S.

    1982-01-01

    CCl4 and CH3OH solvent extractions were performed on the Murray, Murchison, Orgueil and Renazzo carbonaceous chondrites. Delta-D values of +300-+500% are found in the case of the CH3OH-soluble organic matter. The combined C, H and N isotope data makes it unlikely that the CH3OH-soluble components are derivable from, or simply related to, the insoluble organic polymer found in the same meteorites. A relation between the event that formed hydrous minerals in CI1 and CM2 meteorites and the introduction of water- and methanol-soluble organic compounds is suggested. Organic matter soluble in CCl4 has no N, and delta-C-13 values are lower than for CH3OH-soluble phases. It is concluded that there either are large isotopic fractionations for carbon and hydrogen between different soluble organic phases, or the less polar components are partially of terrestrial origin.

  20. 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

  1. Refractoriness in Sustained Visuo-Manual Control: Is the Refractory Duration Intrinsic or Does It Depend on External System Properties?

    PubMed Central

    van de Kamp, Cornelis; Gawthrop, Peter J.; Gollee, Henrik; Loram, Ian D.

    2013-01-01

    Researchers have previously adopted the double stimulus paradigm to study refractoriness in human neuromotor control. Currently, refractoriness, such as the Psychological Refractory Period (PRP) has only been quantified in discrete movement conditions. Whether refractoriness and the associated serial ballistic hypothesis generalises to sustained control tasks has remained open for more than sixty years. Recently, a method of analysis has been presented that quantifies refractoriness in sustained control tasks and discriminates intermittent (serial ballistic) from continuous control. Following our recent demonstration that continuous control of an unstable second order system (i.e. balancing a ‘virtual’ inverted pendulum through a joystick interface) is unnecessary, we ask whether refractoriness of substantial duration (∼200 ms) is evident in sustained visual-manual control of external systems. We ask whether the refractory duration (i) is physiologically intrinsic, (ii) depends upon system properties like the order (0, 1st, and 2nd) or stability, (iii) depends upon target jump direction (reversal, same direction). Thirteen participants used discrete movements (zero order system) as well as more sustained control activity (1st and 2nd order systems) to track unpredictable step-sequence targets. Results show a substantial refractory duration that depends upon system order (250, 350 and 550 ms for 0, 1st and 2nd order respectively, n = 13, p<0.05), but not stability. In sustained control refractoriness was only found when the target reverses direction. In the presence of time varying actuators, systems and constraints, we propose that central refractoriness is an appropriate control mechanism for accommodating online optimization delays within the neural circuitry including the more variable processing times of higher order (complex) input-output relations. PMID:23300430

  2. The in situ bacterial production of fluorescent organic matter; an investigation at a species level.

    PubMed

    Fox, B G; Thorn, R M S; Anesio, A M; Reynolds, D M

    2017-11-15

    Aquatic dissolved organic matter (DOM) plays an essential role in biogeochemical cycling and transport of organic matter throughout the hydrological continuum. To characterise microbially-derived organic matter (OM) from common environmental microorganisms (Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa), excitation-emission matrix (EEM) fluorescence spectroscopy was employed. This work shows that bacterial organisms can produce fluorescent organic matter (FOM) in situ and, furthermore, that the production of FOM differs at a bacterial species level. This production can be attributed to structural biological compounds, specific functional proteins (e.g. pyoverdine production by P. aeruginosa), and/or metabolic by-products. Bacterial growth curve data demonstrates that the production of FOM is fundamentally related to microbial metabolism. For example, the majority of Peak T fluorescence (> 75%) is shown to be intracellular in origin, as a result of the building of proteins for growth and metabolism. This underpins the use of Peak T as a measure of microbial activity, as opposed to bacterial enumeration as has been previously suggested. This study shows that different bacterial species produce a range of FOM that has historically been attributed to high molecular weight allochthonous material or the degradation of terrestrial FOM. We provide definitive evidence that, in fact, it can be produced by microbes within a model system (autochthonous), providing new insights into the possible origin of allochthonous and autochthonous organic material present in aquatic systems. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Emergency Surgery for Refractory Status Epilepticus.

    PubMed

    Botre, Abhijeet; Udani, Vrajesh; Desai, Neelu; Jagadish, Spoorthy; Sankhe, Milind

    2017-08-15

    Management of refractory status epilepticus in children is extremely challenging. Two children with medically refractory status epilepticus, both of whom had lesional pathology on MRI and concordant data on EEG and PET scan. Emergency hemispherotomy performed in both patients. A complete, sustained seizure freedom obtained postoperatively. Emergency surgery is a treatment option in selected cases of drug refractory status epilepticus with lesional pathology and concordant data.

  4. Carbon isotopic studies of organic matter in Precambrian rocks.

    NASA Technical Reports Server (NTRS)

    Oehler, D. Z.; Schopf, J. W.; Kvenvolden, K. A.

    1972-01-01

    A survey has been undertaken of the carbon composition of the total organic fraction of a suite of Precambrian sediments to detect isotopic trends possibly correlative with early evolutionary events. Early Precambrian cherts of the Fig Tree and upper and middle Onverwacht groups of South Africa were examined for this purpose. Reduced carbon in these cherts was found to be isotopically similar to photosynthetically produced organic matter of younger geological age. Reduced carbon in lower Onverwacht cherts was found to be anomalously heavy; it is suggested that this discontinuity may reflect a major event in biological evolution.

  5. Comments on D/H ratios in chondritic organic matter

    NASA Astrophysics Data System (ADS)

    Smith, J. W.; Rigby, D.

    1981-06-01

    D/H ratios in chondritic organic matter are investigated. Demineralized organic residues obtained from previous experiments were dried in a quartz reaction vessel under vacuum for 60 minutes at 250-300 C and then combusted in oxygen for 20 minutes at 850 C. The apparatus is described and the results of the experiments such as D/H ratios in water and measurements on total carbon dioxide are given. Atomic H/C ratios calculated directly from the quantities of carbon dioxide and water recovered, are reported according to Standard Mean Ocean Water and Pee Dee Belemnite, using the customary notation.

  6. Fossil organic matter characteristics in permafrost deposits of the northeast Siberian Arctic

    Treesearch

    Lutz Schirrmeister; Guido Grosse; Sebastian Wetterich; Pier Paul Overduin; Jens Straub; Edward A.G. Schuur; Hans-Wolfgang Hubberton

    2011-01-01

    Permafrost deposits constitute a large organic carbon pool highly vulnerable to degradation and potential carbon release due to global warming. Permafrost sections along coastal and river bank exposures in NE Siberia were studied for organic matter (OM) characteristics and ice content. OM stored in Quaternary permafrost grew, accumulated, froze, partly decomposed, and...

  7. Influence of algal and bacterial particulate organic matter on benzo[a]pyrene bioaccumulation in Daphnia magna.

    PubMed

    Gourlay, Catherine; Mouchel, Jean-Marie; Tusseau-Vuillemin, Marie-Hélène; Garric, Jeanne

    2005-06-15

    In order to better asses the influence of organic matter on the bioavailability of hydrophobic organic contaminants, the effect of algae and POM of bacterial origin on the bioaccumulation of benzo[a]pyrene in Daphnia magna was evaluated. The bioaccumulation was monitored with increasing concentrations of particulate organic matter (POM) and dissolved organic matter (DOM). In all experiments, the presence of POM greatly reduced the bioaccumulation of benzo[a]pyrene. The reduction was more pronounced in the presence of algae, for which we observed a 99%-reduction effect in the presence of 6 x10 (5) cell/mL (equivalent to 5.3 mg C/L). The bioaccumulation of benzo[a]pyrene was decreased by 49% by organic matter of bacterial origin at 4.7 mg C/L. Assuming that benzo[a]pyrene was partitioned between water, DOM and POM and supposing that D. magna accumulated free benzo[a]pyrene via respiration and POM-bond benzo[a]pyrene via ingestion, bioaccumulation data allowed to estimate the dietary uptake rate of benzo[a]pyrene as well as partitioning coefficients K(POC) and K(DOC). Despite the ingestion of contaminated particles, we could not observe any dietary uptake of benzo[a]pyrene in daphnids. We verified, as usually supposed, that the bioaccumulation of benzo[a]pyrene to D. magna occurs mainly via direct contact. Very high partitioning coefficients (log K(POC) between 5.2 and 6.2) were estimated. This study pointed out the great influence of biogenic organic matter on the fate and the bioavailability of benzo[a]pyrene in aquatic ecosystems.

  8. Removal of High -Concentration and Refractory Organic Matter from Diosgenin Manufacture Wastewater : a case study of a demonstration project in Hubei Province, P R China

    NASA Astrophysics Data System (ADS)

    Bao, J.; Wang, L.

    2009-12-01

    Wastewater from diosgenin manufacture is dark brown (3,500 ~4,000 times of the chroma) and acidic(pH=0.8~1.5)with high concentration of organic matter(COD=25,000~38,000 mg/L)and poor biodegradability(BOD5/COD= 0.25~0.30). It is highly toxic to biota due to the water-soluble saponin, tannins and pectin. Therefore removal of the organic matter is of great importance before the discharge of the wastewater into the environment. Here we presented a set of data from a demonstration project in Hubei province, P R China with an improved technics. This technics, focusing on the treatment of diosgenin wastewater, included hydrolytic acidification, internal electrolysis, neutralization, aerating-improved Up-flow Anaerobic Sludge Bed (UASB) and bio-contact oxidation treatment in sequence to remove the organic matter. After 60 days of starting-up, the water quality from hydrolytic acidification reactor was greatly improved. The effluent became clear, indicating the obvious removal of suspended solids in the water; the ratio of BOD/COD increased to 0.44, suggesting an significant increase of biodegradability; the content of volatile fatty acid (VFA) increased from 22.6 mmol/L to 86.8 mmol/L and the volume loading of COD reached 9.48 kg COD/(m3d). Basically at this stage the removal efficiency of COD was stabilized at 25%. Further treatment was conducted on the effluent from hydrolytic acidification reactor through the Improved UASB Reactor after the internal electrolysis and neutralization. The Improved UASB Reactor can start up at room temperature with an influent of 1,500 mg/L COD and inflow rate of 50(m3/d). Then, temperature was increased gradually to 38 oC (± 2 oC) to optimize the growth of the mesophilic anaerobes in the reactor. The content of VFA of the effluent was controlled below 8 mmol/L to guarantee the pH in the range of 6.8~7.2. After 150 days of debugging, the COD of the influent to UASB increased to 9,600 mg/L, hydraulic retaining time (HRT) was around 70 hrs

  9. Removal of dissolved organic matter by anion exchange: Effect of dissolved organic matter properties

    USGS Publications Warehouse

    Boyer, T.H.; Singer, P.C.; Aiken, G.R.

    2008-01-01

    Ten isolates of aquatic dissolved organic matter (DOM) were evaluated to determine the effect that chemical properties of the DOM, such as charge density, aromaticity, and molecular weight, have on DOM removal by anion exchange. The DOM isolates were characterized asterrestrial, microbial, or intermediate humic substances or transphilic acids. All anion exchange experiments were conducted using a magnetic ion exchange (MIEX) resin. The charge density of the DOM isolates, determined by direct potentiometric titration, was fundamental to quantifying the stoichiometry of the anion exchange mechanism. The results clearly show that all DOM isolates were removed by anion exchange; however, differences among the DOM isolates did influence their removal by MIEX resin. In particular, MIEX resin had the greatest affinity for DOM with high charge density and the least affinity for DOM with low charge density and low aromaticity. This work illustrates that the chemical characteristics of DOM and solution conditions must be considered when evaluating anion exchange treatment for the removal of DOM. ?? 2008 American Chemical Society.

  10. Effects of effluent organic matter characteristics on the removal of bulk organic matter and selected pharmaceutically active compounds during managed aquifer recharge: Column study

    NASA Astrophysics Data System (ADS)

    Maeng, Sung Kyu; Sharma, Saroj K.; Abel, Chol D. T.; Magic-Knezev, Aleksandra; Song, Kyung-Guen; Amy, Gary L.

    2012-10-01

    Soil column experiments were conducted to investigate the effects of effluent organic matter (EfOM) characteristics on the removal of bulk organic matter (OM) and pharmaceutically active compounds (PhACs) during managed aquifer recharge (MAR) treatment processes. The fate of bulk OM and PhACs during an MAR is important to assess post-treatment requirements. Biodegradable OM from EfOM, originating from biological wastewater treatment, was effectively removed during soil passage. Based on a fluorescence excitation-emission matrix (F-EEM) analysis of wastewater effluent-dominated (WWE-dom) surface water (SW), protein-like substances, i.e., biopolymers, were removed more favorably than fluorescent humic-like substances under oxic compared to anoxic conditions. However, there was no preferential removal of biopolymers or humic substances, determined as dissolved organic carbon (DOC) observed via liquid chromatography with online organic carbon detection (LC-OCD) analysis. Most of the selected PhACs exhibited removal efficiencies of greater than 90% in both SW and WWE-dom SW. However, the removal efficiencies of bezafibrate, diclofenac and gemfibrozil were relatively low in WWE-dom SW, which contained more biodegradable OM than did SW (copiotrophic metabolism). Based on this study, low biodegradable fractions such as humic substances in MR may have enhanced the degradation of diclofenac, gemfibrozil and bezafibrate by inducing an oligotrophic microbial community via long term starvation. Both carbamazepine and clofibric acid showed persistent behaviors and were not influenced by EfOM.

  11. Effects of augmentation of coarse particulate organic matter on metabolism and nutrient retention in hyporheic sediments

    Treesearch

    C.L. Crenshaw; H.M. Valett; J.R. Webster

    2002-01-01

    1. Metabolic and biogeochemical processes in hyporheic zones may depend on inputs of coarse particulate organic matter. Our research focused on how differing quantity and quality of organic matter affects metabolism and nutrient retention in the hyporheic zone of a first-order Appalachian stream. 2. Sixteen plots were established on a tributary of Hugh White Creek, NC...

  12. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) coupled to XAD fractionation: Method to algal organic matter characterization.

    PubMed

    Nicolau, Rudy; Leloup, Maud; Lachassagne, Delphine; Pinault, Emilie; Feuillade-Cathalifaud, Geneviève

    2015-05-01

    This work is focused on the development of an analytical procedure for the improvement of the Organic Matter structure characterization, particularly the algal matter. Two fractions of algal organic matter from laboratory cultures of algae (Euglena gracilis) and cyanobacteria (Microcystis aeruginosa) were extracted with XAD resins. The fractions were studied using laser desorption ionization (LDI) and Matrix-Assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). A comparison with the natural organic matter characteristics from commercial humic acids and fulvic acids extracted from Suwannee River was performed. Results show that algal and natural organic matters have unique quasi-polymeric structures. Significant repeating patterns were identified. Different fractions extracted from organic matter with common origin had common structures. Thus, 44, 114 and 169Da peaks separation for fractions from E. gracilis organic matter and 28, 58 and 100Da for M. aeruginosa ones were clearly observed. Using the developed protocol, a structural scheme and organic matter composition were obtained. The range 600-2000Da contained more architectural composition differences than the range 100-600Da, suggesting that organic matter is composed of an assembly of common small molecules. Associated to specific monomers, particular patterns were common to all samples but assembly and resulting structure were unique for each organic matter. Thus, XAD fractionation coupled to mass spectroscopy allowed determining a specific fingerprint for each organic matter. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. The source and distribution of thermogenic dissolved organic matter in the ocean

    NASA Astrophysics Data System (ADS)

    Dittmar, T.; Suryaputra, I. G. N. A.; Paeng, J.

    2009-04-01

    Thermogenic organic matter (ThOM) is abundant in the environment. ThOM is produced at elevated temperature and pressure in deep sediments and earth's crust, and it is also a residue of fossil fuel and biomass burning ("black carbon"). Because of its refractory character, it accumulates in soils and sediments and, therefore, may sequester carbon from active cycles. It was hypothesized that a significant component of marine dissolved organic matter (DOM) might be thermogenic. Here we present a detailed data set on the distribution of thermogenic DOM in major water masses of the deep and surface ocean. In addition, several potential sources of thermogenic DOM to the ocean were investigated: active seeps of brine fluids in the deep Gulf of Mexico, rivers, estuaries and submarine groundwaters. Studies on deep-sea hydrothermal vents and aerosol deposition are ongoing. All DOM samples were isolated from seawater via solid phase extraction (SPE-DOM). ThOM was quantified in the extracts as benzene-polycarboxylic acids (BPCAs) after nitric acid oxidation via high-performance liquid chromatography and diode array detection (HPLC-DAD). BPCAs are produced exclusively from fused ring systems and are therefore unambiguous molecular tracers for ThOM. In addition to BPCA determination, the molecular composition and structure of ThOM was characterized in detail via ultrahigh resolution mass spectrometry (FT-ICR-MS). All marine and river DOM samples yielded significant amounts of BPCAs. The cold seep system in the deep Gulf of Mexico, but also black water rivers (like the Suwannee River) were particularly rich in ThOM. Up to 10% of total dissolved organic carbon was thermogenic in both systems. The most abundant BPCA was benzene-pentacarboxylic acid (B5CA). The molecular composition of BPCAs and the FT-ICR-MS data indicate a relatively small number (5-8) of fused aromatic rings per molecule. Overall, the molecular BPCA patterns were very similar independent of the source of Th

  14. Particulate organic matter in rivers of Fukushima: An unexpected carrier phase for radiocesiums.

    PubMed

    Naulier, Maud; Eyrolle-Boyer, Frédérique; Boyer, Patrick; Métivier, Jean-Michel; Onda, Yuichi

    2017-02-01

    The role of particulate organic matter in radiocesium transfers from soils to rivers was investigated in areas contaminated by the Fukushima Daiichi Nuclear Power Plant accident. Suspended and deposited sediments, filtered water, macro organic debris and dead leaves were sampled along the six most contaminated coastal river catchments of the Fukushima prefecture in the early autumns 2013 and 2014. Radiocesium concentrations of river samples and total organic carbon concentrations in suspended and deposited sediments were measured. Radiocesium concentrations of suspended and deposited sediments were significantly correlated to 137 Cs inventories in soils and total organic carbon. The distributions of radiocesium between the organic and mineral phases of both types of sediment were assessed by using a modelling approach. The results suggest that, during the early autumn season, the organic fraction was the main phase that carried the radiocesiums in deposited sediments and in suspended sediments for suspended loads <25mg·L -1 . For higher suspended loads like those occurring during typhoon periods, the mineral fraction was the main carrier phase. Thus, high apparent distribution coefficient values noted by various authors in Fukushima could be attributed to the high radiocesium contents of particulate organic matter. Since it is well known that organic compounds generally do not significantly adsorb radiocesium onto specific sites, several hypotheses are suggested: 1) Radiocesiums may have been absorbed into organic components at the early stage of atmospheric radioactive deposits and/or later due to biomass recycling and 2) Those elements would be partly carried by glassy hot particles together with organic matter transported by rivers in Fukushima. Both hypotheses would lead to conserve the amount of radiocesiums associated with particles during their transfers from the contaminated areas to the marine environment. Finally, such organically bound radiocesium would

  15. Updates in Refractory Status Epilepticus

    PubMed Central

    Mahulikar, Advait; Suchdev, Kushak; Shah, Aashit

    2018-01-01

    Refractory status epilepticus is defined as persistent seizures despite appropriate use of two intravenous medications, one of which is a benzodiazepine. It can be seen in up to 40% of cases of status epilepticus with an acute symptomatic etiology as the most likely cause. New-onset refractory status epilepticus (NORSE) is a recently coined term for refractory status epilepticus where no apparent cause is found after initial testing. A large proportion of NORSE cases are eventually found to have an autoimmune etiology needing immunomodulatory treatment. Management of refractory status epilepticus involves treatment of an underlying etiology in addition to intravenous anesthetics and antiepileptic drugs. Alternative treatment options including diet therapies, electroconvulsive therapy, and surgical resection in case of a focal lesion should be considered. Short-term and long-term outcomes tend to be poor with significant morbidity and mortality with only one-third of patients reaching baseline neurological status. PMID:29854452

  16. Abemaciclib in Children With DIPG or Recurrent/Refractory Solid Tumors

    ClinicalTrials.gov

    2017-07-14

    Diffuse Intrinsic Pontine Glioma; Brain Tumor, Recurrent; Solid Tumor, Recurrent; Neuroblastoma, Recurrent, Refractory; Ewing Sarcoma, Recurrent, Refractory; Rhabdomyosarcoma, Recurrent, Refractory; Osteosarcoma, Recurrent, Refractory; Rhabdoid Tumor, Recurrent, Refractory

  17. PHOTOCHEMICAL ALTERATION OF DISSOLVED ORGANIC MATTER: EFFECTS ON THE CONCENTRATION AND ACIDITIES OF IONIZABLE SITES IN DISSOLVED ORGANIC MATTER IN THE SATILLA RIVER OF GEORGIA, USA

    EPA Science Inventory

    The acid-base properties of humic substances, the major component of dissolved organic matter (DOM), area major control on the alkalinity, or acid neutralizing capacity of freshwater systems. Alkalinity is one of the fundamental parameters measured in aquatic sciences, and is an ...

  18. Evolution of organic matter in Orgueil, Murchison and Renazzo during parent body aqueous alteration: In situ investigations

    NASA Astrophysics Data System (ADS)

    Le Guillou, Corentin; Bernard, Sylvain; Brearley, Adrian J.; Remusat, Laurent

    2014-04-01

    Chondrites accreted the oldest solid materials in the solar system including dust processed in the protoplanetary disk and diverse organic compounds. After accretion, asteroidal alteration may have impacted organic particles in various ways. To constrain these processes, we conducted a comprehensive study of organics disseminated within the matrices of the three carbonaceous chondrite falls, Renazzo (CR2), Murchison (CM2) and Orgueil (CI). By combining synchrotron-based STXM and TEM analyses on FIB sections of samples previously characterized by NanoSIMS, we investigated the influence of aqueous alteration on the morphology, isotopic signature, molecular structure, spatial distribution, and mineralogical environment of the organic matter within the matrices. Two different populations of materials are distinguishable: sub-micrometric individual grains, likely dominated by insoluble compounds and diffuse organic matter, finely interspersed within phyllosilicates and/or (amorphous) nanocarbonates at the nanometer scale. We suggest that this latter component, which is depleted in aromatics and enriched in carboxylic functional groups, may be dominated by soluble compounds. Organic matter in Renazzo (CR) mainly consists of chemically-homogeneous individual grains surrounded by amorphous and nanocrystalline phyllosilicates. Evidence of connectivity between organic grains and fractures indicates that redistribution has occurred: some areas containing diffuse organic matter can be observed. This diffuse organic component is more abundant in Murchison (CM) and Orgueil (CI). This is interpreted as resulting from fluid transport at the micrometer scale and encapsulation within recrystallized alteration phases. In contrast to Renazzo, organic grains in Murchison and Orgueil display strong chemical heterogeneities, likely related to chemical evolution during aqueous alteration. The observations suggest that the altering fluid was a brine with elevated concentrations of both

  19. The global distribution and dynamics of chromophoric dissolved organic matter.

    PubMed

    Nelson, Norman B; Siegel, David A

    2013-01-01

    Chromophoric dissolved organic matter (CDOM) is a ubiquitous component of the open ocean dissolved matter pool, and is important owing to its influence on the optical properties of the water column, its role in photochemistry and photobiology, and its utility as a tracer of deep ocean biogeochemical processes and circulation. In this review, we discuss the global distribution and dynamics of CDOM in the ocean, concentrating on developments in the past 10 years and restricting our discussion to open ocean and deep ocean (below the main thermocline) environments. CDOM has been demonstrated to exert primary control on ocean color by its absorption of light energy, which matches or exceeds that of phytoplankton pigments in most cases. This has important implications for assessing the ocean biosphere via ocean color-based remote sensing and the evaluation of ocean photochemical and photobiological processes. The general distribution of CDOM in the global ocean is controlled by a balance between production (primarily microbial remineralization of organic matter) and photolysis, with vertical ventilation circulation playing an important role in transporting CDOM to and from intermediate water masses. Significant decadal-scale fluctuations in the abundance of global surface ocean CDOM have been observed using remote sensing, indicating a potentially important role for CDOM in ocean-climate connections through its impact on photochemistry and photobiology.

  20. SINTERED REFRACTORY MASS

    DOEpatents

    Williams, A.E.

    1955-09-01

    A method is given for joining sintered masses of refractory compounds. It consists in maintaining the masses in contact with each other by application of a moderate pressure, while they are at sintering temperature. The sintered masses are subjected to am applied pressure of about 1/2 to 1 ton per square inch of the surface in contact for about 10 minutes, and the temperature employed may be fropn about 1400 deg C to 2000 deg C. Refractory oxides to which the invention may be applied are beryllia, alumina, thoria, and magnesia.