WorldWideScience

Sample records for buried organic matter

  1. Soil organic matter stabilization in buried paleosols of the Great Plains

    Science.gov (United States)

    Chaopricha, N. T.; Marin-Spiotta, E.; Mason, J. A.; Mueller, C. W.

    2010-12-01

    Understanding the mechanisms that control soil organic matter (SOM) stabilization is important for understanding how soil carbon is sequestered over millennia, and for predicting how future disturbances may affect soil carbon stocks. We are studying the mechanisms controlling SOM stabilization in the Brady Soil, a buried paleosol in Holocene loess deposits spanning much of the central Great Plains of the United States. The Brady Soil developed 9,000-13,500 years ago during a time of warming and drying that resulted in a shift from C3 to C4 dominated plants. The Brady soil is unusual in that it has very dark coloring, although it contains less than pyrolysis GC/MS to determine likely sources for the SOM: microbial vs plant. Combining information on the physical location of SOM in the soil, its chemical composition, decomposability, and radiocarbon based mean residence time estimates will allow us to determine (a) the source of the dark coloration in the Brady soil, (b) the mechanisms that have contributed to its preservation for the last 10,000 years, and (c) the likelihood this large soil C stock will be lost to the atmosphere if exposed during disturbance.

  2. Mass loss and nutrient concentrations of buried wood as a function of organic matter removal, soil compaction, and vegetation control in a regenerating oak-pine forest

    Science.gov (United States)

    Felix Ponder; John M. Kabrick; Mary Beth Adams; Deborah S. Page-Dumroese; Marty F. Jurgensen

    2017-01-01

    Mass loss and nutrient concentrations of northern red oak (Quercus rubra) and white oak (Q. alba) wood stakes were measured 30 months after their burial in the upper 10 cm of soil in a regenerating forest after harvesting and soil disturbance. Disturbance treatments were two levels of organic matter (OM) removal (only...

  3. Probing Molecular Organization and Electronic Dynamics at Buried Organic Interfaces

    Science.gov (United States)

    Roberts, Sean

    2015-03-01

    Organic semiconductors are a promising class of materials due to their ability to meld the charge transport capabilities of semiconductors with many of the processing advantages of plastics. In thin film organic devices, interfacial charge transfer often comprises a crucial step in device operation. As molecular materials, the density of states within organic semiconductors often reflect their intermolecular organization. Truncation of the bulk structure of an organic semiconductor at an interface with another material can lead to substantial changes in the density of states near the interface that can significantly impact rates for interfacial charge and energy transfer. Here, we will present the results of experiments that utilize electronic sum frequency generation (ESFG) to probe buried interfaces in these materials. Within the electric dipole approximation, ESFG is only sensitive to regions of a sample that experience a breakage of symmetry, which occurs naturally at material interfaces. Through modeling of signals measured for thin organic films using a transfer matrix-based formalism, signals from buried interfaces between two materials can be isolated and used to uncover the interfacial density of states.

  4. Chemodestructive fractionation of soil organic matter

    Science.gov (United States)

    Popov, A. I.; Rusakov, A. V.

    2016-06-01

    The method of chemodestructive fractionation is suggested to assess the composition of soil organic matter. This method is based on determination of the resilience of soil organic matter components and/or different parts of organic compounds to the impact of oxidizing agents. For this purpose, a series of solutions with similar concentration of the oxidant (K2Cr2O7), but with linearly increasing oxidative capacity was prepared. Chemodestructive fractionation showed that the portion of easily oxidizable (labile) organic matter in humus horizons of different soil types depends on the conditions of soil formation. It was maximal in hydromorphic soils of the taiga zone and minimal in automorphic soils of the dry steppe zone. The portion of easily oxidizable organic matter in arable soils increased with an increase in the rate of organic fertilizers application. The long-lasting agricultural use of soils and burying of the humus horizons within the upper one-meter layer resulted in the decreasing content of easily oxidizable organic matter. It was found that the portion of easily oxidizable organic matter decreases by the mid-summer or fall in comparison with the spring or early summer period.

  5. Is old organic matter simple organic matter?

    Science.gov (United States)

    Nunan, Naoise; Lerch, Thomas; Pouteau, Valérie; Mora, Philippe; Changey, Fréderique; Kätterer, Thomas; Herrmann, Anke

    2016-04-01

    Bare fallow soils that have been deprived of fresh carbon inputs for prolonged periods contain mostly old, stable organic carbon. In order to shed light on the nature of this carbon, the functional diversity profiles (MicroResp™, Biolog™ and enzyme activity spectra) of the microbial communities of long-term barefallow soils were analysed and compared with those of the microbial communities from their cultivated counterparts. The study was based on the idea that microbial communities adapt to their environment and that therefore the catabolic and enzymatic profiles would reflect the type of substrates available to the microbial communities. The catabolic profiles suggested that the microbial communities in the long-term bare-fallow soil were exposed to a less diverse range of substrates and that these substrates tended to be of simpler molecular forms. Both the catabolic and enzyme activity profiles suggested that the microbial communities from the long-term bare-fallow soils were less adapted to using polymers. These results do not fit with the traditional view of old, stable carbon being composed of complex, recalcitrant polymers. An energetics analysis of the substrate use of the microbial communities for the different soils suggested that the microbial communities from the long-term bare-fallow soils were better adapted to using readily oxidizable,although energetically less rewarding, substrates. Microbial communities appear to adapt to the deprivation of fresh organic matter by using substrates that require little investment.

  6. Organic Matter Management

    Energy Technology Data Exchange (ETDEWEB)

    Izaurralde, Roberto C.; Cerri, Carlos C.

    2002-01-01

    Soil organic matter (S)M) is an essential attribute of soil quality with a key role in soil conservation and sustainable agriculture. Many practices-some involving land use changes-have been shown to increase SOM and thus received considerable attention for their possible role in climate change mitigation. Carbon sequestration in managed soils occurs when there is a net removal of atmospheric CO2 because of the balance between carbon inputs (net primary productivity) and outputs (soil respiration, management-related C emissions). Soil C sequestration has the additional appeal that all its practices conform to principles of sustainable agriculture (e.g., reduced tillage, erosion control, diverse cropping systems, improved soil fertility). Long-term field experiments have been instrumental to increase our understanding of SOM dynamics. This chapter presents fundamental concepts to guide readers on the role of SOM in sustainable agriculture and climate change mitigation.

  7. Arctic River organic matter transport

    Science.gov (United States)

    Raymond, Peter; Gustafsson, Orjan; Vonk, Jorien; Spencer, Robert; McClelland, Jim

    2016-04-01

    Arctic Rivers have unique hydrology and biogeochemistry. They also have a large impact on the Arctic Ocean due to the large amount of riverine inflow and small ocean volume. With respect to organic matter, their influence is magnified by the large stores of soil carbon and distinct soil hydrology. Here we present a recap of what is known of Arctic River organic matter transport. We will present a summary of what is known of the ages and sources of Arctic River dissolved and particulate organic matter. We will also discuss the current status of what is known about changes in riverine organic matter export due to global change.

  8. Dissolved Organic Matter in Freshwaters

    Science.gov (United States)

    Perdue, E. M.; Ritchie, J. D.

    2003-12-01

    Organic matter in freshwaters exists as dissolved molecules, colloids, and particles. It is appropriate to regard these distinctions as dynamic, however, because organic matter can be interconverted readily between these forms by dissolution and precipitation, sorption and desorption, aggregation and disaggregation, etc. Dissolved organic matter (DOM), the subject of this chapter, is defined operationally as the fraction of organic matter in a water sample that passes through a 0.45 μm filter. In the authors' opinion, the scientific literature on organic matter in freshwaters will be better reflected in this review, if data are considered without regard to the manner in which water samples may have been filtered. This more general approach is warranted because: * many submicron colloids and some microorganisms can pass through 0.45 μm filters; * the effective pore size of a 0.45 μm filter is usually unknown, because it is decreased by partial clogging during the filtration of a water sample; * some important studies have been conducted on unfiltered samples or on samples that were filtered through other types of filters; and * some important studies have been conducted on samples that were concentrated with ultrafiltration (UF), nanofiltration (NF), or reverse osmosis (RO) membranes.As methods for fractionation and isolation of organic matter in freshwaters have evolved, and as the intensity of research has waxed and waned in various academic disciplines, a rich and potentially confusing nomenclature has evolved for organic matter in freshwaters. Some of the more commonly encountered descriptors and their associated acronyms, if any, are yellow organic acids (YOAs), aquatic humus, DOM, and natural organic matter (NOM). Regardless of the terminology used in the original literature, the organic matter in freshwaters is referred to as DOM in this review, except when it is necessary to be more specific.

  9. Making organization research matter

    DEFF Research Database (Denmark)

    Flyvbjerg, Bent

    2006-01-01

    research or any of the social sciences. Second, we must address problems that matter to groups in the local, national, and global communities in which we live, and we must do it in ways that matter; we must focus on issues of context, values, and power, as advocated by great social scientists from...... Aristotle and Machiavelli to Max Weber and Pierre Bourdieu. Finally, we must effectively and dialogically communicate the results of our research to our fellow citizens and carefully listen to their feedback. If we do this – focus on specific values and interests in the context of particular power relations...

  10. The destruction of organic matter

    CERN Document Server

    Gorsuch, T T

    1970-01-01

    International Series of Monographs in Analytical Chemistry, Volume 39: The Destruction of Organic Matter focuses on the identification of trace elements in organic compounds. The monograph first offers information on the processes involved in the determination of trace elements in organic matters, as well as the methods not involving complete destruction of these elements. The text surveys the sources of errors in the processes responsible in pinpointing elements in organic compounds. These processes include sampling, disruption of the samples, manipulation, and measurements. The book

  11. Organic matter in meteorites.

    Science.gov (United States)

    Llorca, Jordi

    2004-12-01

    Some primitive meteorites are carbon-rich objects containing a variety of organic molecules that constitute a valuable record of organic chemical evolution in the universe prior to the appearance of microorganisms. Families of compounds include hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids, amino acids, amines, amides, heterocycles, phosphonic acids, sulfonic acids, sugar-related compounds and poorly defined high-molecular weight macromolecules. A variety of environments are required in order to explain this organic inventory, including interstellar processes, gas-grain reactions operating in the solar nebula, and hydrothermal alteration of parent bodies. Most likely, substantial amounts of such organic materials were delivered to the Earth via a late accretion, thereby providing organic compounds important for the emergence of life itself, or that served as a feedstock for further chemical evolution. This review discusses the organic content of primitive meteorites and their relevance to the build up of biomolecules.

  12. Feed and organic matter

    DEFF Research Database (Denmark)

    Dalsgaard, Anne Johanne Tang

    2011-01-01

    Organic waste from fish production is conventionally measured as BOD5 (biological oxygen demand measured during 5 days) and COD (chemical oxygen demand (includes BOD5)). Organic waste is of particular concern for several reasons. The easily degradable part (BOD5) may have an immediate, negative...... impact on the receiving water body by reducing dissolved oxygen concentrations and increasing sedimentation. Within aquaculture systems, a high organic load may affect fish health and performance directly (e.g., gill disease) as well as indirectly (proliferation of pathogenic bacteria and parasites......, reduction of dissolved oxygen concentrations, etc.). In recirculating aquaculture systems (RAS), a high organic load caused by limited water exchange may affect biofilter performance by favouring heterotrophic bacteria at the expense of autotrophic, nitrifying bacteria. Organic waste in RAS primarily...

  13. Organic Matter in the Contemporary Ocean

    Science.gov (United States)

    Eglinton, T. I.; Repeta, D. J.

    2003-12-01

    liquid chromatography/mass spectrometry techniques provide structural information on polar macromolecules that have previously been beyond the scope of established methods. In addition to technological advances, large multidisciplinary field programs have provided important frameworks and contexts within which to interpret organic geochemical data, while novel sampling techniques have been developed that allow for the collection of more representative samples and their detailed analytical manipulation. Two particular analytical approaches are highlighted in this chapter - NMR spectroscopy as a powerful tool for structural characterization of complex macromolecules, and compound specific carbon isotope (13C and 14C) analysis as probes for the cycling of organic matter in the ocean through space and time.Finally, we outline new as well as unresolved questions which provide future challenges for marine organic biogeochemists, and discuss emerging analytical approaches that may shed new light on organic matter cycling in the oceans. For example, (i) the source of "old" dissolved organic carbon (DOC) in the deep sea has yet to be resolved; (ii) the molecular-level composition of the majority of organic matter buried in marine sediments evades elucidation; and (iii) while planktonic archea have been found to be amongst the most abundant organisms in the ocean, their role in biogeochemical cycles and their legacy in the sedimentary record are only beginning to be considered. Such fundamental observations and questions continue to challenge us, and limit our understanding of the processes underpinning organic matter cycling in the oceans.The discipline of marine organic geochemistry has expanded and evolved greatly in recent years. Hence, we have had to be selective in our coverage of new developments. This review, therefore, is by no means comprehensive and there are many important and exciting aspects of marine organic geochemistry that we have not covered. Comprehensive

  14. Long-term dynamics of buried organic carbon in colluvial soils

    Directory of Open Access Journals (Sweden)

    Z. Wang

    2013-08-01

    Full Text Available Colluvial soils are enriched in soil organic carbon (SOC in comparison to the soils of upslope areas due to the deposition and subsurface burial of SOC. It has been suggested that the burial of SOC has important implications for the global carbon cycle, but the long-term dynamics of buried SOC remains poorly constrained. We address this issue by determining the SOC burial efficiency (i.e., the fraction of originally deposited SOC that is preserved in colluvial deposits of buried SOC as well as the SOC stability in colluvial soils. We quantify the turnover rate of deposited SOC by establishing sediment and SOC burial chronologies. The SOC stability is derived from soil incubation experiments and the δ13C values of SOC. The C burial efficiency was found to decrease exponentially with time reaching a constant ratio of approximately 17%. This exponential decrease is attributed to the increasing recalcitrance of buried SOC with time and a less favourable environment for SOC decomposition with increasing depth. Buried SOC is found to be more stable and degraded in comparison to SOC sampled at the same depth at a stable site. This is due to preferential mineralization of the labile fraction of deposited SOC resulting in enrichment of more degraded and recalcitrant SOC in colluvial soils. In order to better understand the long-term effects of soil erosion for the global C cycle, the temporal variation of deposited SOC and its controlling factors need to be characterized and quantified.

  15. Radionuclide - Soil Organic Matter Interactions

    DEFF Research Database (Denmark)

    Carlsen, Lars

    1985-01-01

    Interactions between soil organic matter, i.e. humic and fulvic acids, and radionuclides of primary interest to shallow land burial of low activity solid waste have been reviewed and to some extent studied experimentally. The radionuclides considered in the present study comprise cesium, strontium...

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

    NARCIS (Netherlands)

    Woulds, C.; Middelburg, J.J.; Cowie, G.L.

    2012-01-01

    Of the factors which control the quantity and composition of organic matter (OM) buried in marine sediments, the links between infaunal ingestion and gut passage and sediment geochemistry have received relatively little attention. This study aimed to use feeding experiments and novel isotope tracing

  17. Organic matter in the universe

    CERN Document Server

    Kwok, Sun

    2012-01-01

    Authored by an experienced writer and a well-known researcher of stellar evolution, interstellar matter and spectroscopy, this unique treatise on the formation and observation of organic compounds in space includes a spectroscopy refresher, as well as links to geological findings and finishes with the outlook for future astronomical facilities and solar system exploration missions. A whole section on laboratory simulations includes the Miller-Urey experiment and the ultraviolet photolysis of ices.

  18. Temperature-driven decoupling of key phases of organic matter degradation in marine sediments

    OpenAIRE

    Weston, Nathaniel B.; Joye, Samantha B.

    2005-01-01

    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 tempe...

  19. Self-organized growth of nanoparticles on a surface patterned by a buried dislocation network.

    Science.gov (United States)

    Leroy, F; Renaud, G; Letoublon, A; Lazzari, R; Mottet, C; Goniakowski, J

    2005-10-28

    The self-organized growth of Co nanoparticles is achieved at room temperature on an inhomogenously strained Ag(001) surface arising from an underlying square misfit dislocation network of 10 nm periodicity buried at the interface between a 5 nm-thick Ag film and a MgO(001) substrate. This is revealed by in situ grazing-incidence small-angle x-ray scattering. Simulations of the data performed in the distorted wave Born approximation framework demonstrate that the Co clusters grow above the dislocation crossing lines. This is confirmed by molecular dynamic simulations indicating preferential Co adsorption on tensile sites.

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

    Science.gov (United States)

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

    2015-01-01

    The term organic matter refers to the remnants of all living material. This can include fallen leaves, yard waste, animal waste, downed timber, or the remains of any other plant and animal life. Organic matter is abundant both on land and in water. Investigating organic matter is necessary for understanding the fate and transport of carbon (a major constituent of organic matter).

  1. Predicting the long-term fate of buried organic carbon in colluvial soils

    Science.gov (United States)

    Wang, Zhengang; Van Oost, Kristof; Govers, Gerard

    2015-04-01

    A significant part of the soil organic carbon (SOC) that is eroded in uplands is deposited and buried in colluvial settings. Understanding the fate of this deposited soil organic carbon is of key importance for the understanding of the role of (accelerated) erosion in the global C cycle: the residence time of the deposited carbon will determine if, and for how long, accelerated erosion due to human disturbance will induce sequestration of SOC from the atmosphere to the soil. Experimental studies may provide useful information, but, given the time scale under consideration, the response of the colluvial SOC can only be simulated using numerical models which need careful calibration using field data. In this study, we present a depth explicit SOC model (ICBM-DE) including soil profile evolution due to sedimentation to simulate the long-term C dynamics in colluvial soils. The SOC profile predicted by our model is in good agreement with field observations. The C burial efficiency (the ratio of current C content of the buried sediments to the original C content at the time of sedimentation) of deposited sediments exponentially decreases with time and gradually reached an equilibrium value. This equilibrium C burial efficiency is positively correlated with the sedimentation rate. The sedimentation rate is crucial for the long-term dynamics of the deposited SOC as it controls the time that buried sediments spend at a given soil depth, thereby determining its temporal evolution of C input and decomposition rate during the burial process: C input and decomposition rate vary with depth due to the vertical variation of root distribution and soil environmental factors such as (but not limited to) humidity, temperature and aeration. The model demonstrates that, for the profiles studied, it takes ca. 300 yr for the buried SOC to lose half of its C load. It would also take centuries for the SOC accumulated in colluvial soils over the past decades due to soil redistribution under

  2. Photodissolution of soil organic matter

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  4. Organic matter and soil moisture content and double cropping with organic matter sourceplants

    OpenAIRE

    John Bako Baon; Aris Wibawa

    2005-01-01

    Double cropping of coffee with organic matter source plants is thought to increase organic matter content of soil. This study examined the effect of double cropping of coffee and organic matter source plants on soil organic matter content and yield of coffee plants. Arabica coffee trees in Andungsari Experimental Station (Bondowoso district), 1400 m asl. and climate type C; and Robusta coffee trees in Sumberasin Experimental Station (Malang district), 550 m asl. and climate type C, were used ...

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

    Science.gov (United States)

    Edwin A. Hebb

    1980-01-01

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

  6. Organic matter mineralization in marine systems

    NARCIS (Netherlands)

    Middelburg, J.J.; Vlug, T.; Van der Nat, F.J.

    1993-01-01

    Many of the reactions and biogeochemical processes that occur in the marine environment are related directly or indirectly to the mineralization of organic matter. Decomposition of organic matter is responsible for the recycling of essential nutrients, for the oxygen balance of the ocean and its sed

  7. Organic matter mineralization in marine systems

    NARCIS (Netherlands)

    Middelburg, J.J.; Vlug, T.; Van der Nat, F.J.

    1993-01-01

    Many of the reactions and biogeochemical processes that occur in the marine environment are related directly or indirectly to the mineralization of organic matter. Decomposition of organic matter is responsible for the recycling of essential nutrients, for the oxygen balance of the ocean and its

  8. When Organization Fails: Why Authority Matters

    DEFF Research Database (Denmark)

    Blaschke, Steffen

    2015-01-01

    Review of: James R. Taylor and Elizabeth J. Van Every / When Organization Fails: Why Authority Matters. (New York: Routledge, 2014. 220 pp. ISBN: 978 0415741668)......Review of: James R. Taylor and Elizabeth J. Van Every / When Organization Fails: Why Authority Matters. (New York: Routledge, 2014. 220 pp. ISBN: 978 0415741668)...

  9. Natural Organic Matter in Ecosystems - a Review

    Directory of Open Access Journals (Sweden)

    Kosobucki Przemysław

    2014-12-01

    Full Text Available One of the most essential parameters limiting the potential use of the ecosystem (soil, water is the content of the organic matter. The natural organic matter (NOM is a ubiquitous component of the lithosphere and hydrosphere that constitutes one of the largest reservoirs of the carbon in the environment. Natural organic substances play several important functions in ecosystems and they are necessary for their normal functioning. Despite many years of the research and using many advanced analytical techniques, their structure has not been fully explained. The main aim of this review is to present the actual state of the knowledge about the natural organic matter and provide a comprehensive overview of the research that has explored up to date in this matter. The additional attention was focused on the relations within and between humic and fulvic acids in terrestrial and aquatic environments. Special attention is focused on the analytical methods used to analysis natural organic matter

  10. Probing of Charge Transfer States at Buried Organic Interfaces with Even-Order Spectroscopy

    Science.gov (United States)

    Pandey, Ravindra; Moon, Aaron; Roberts, Sean

    Organic thin film photovoltaics (OPV) are an emerging economically competitive technology that combines manufacturing adaptability, low-cost processing and a lightweight, flexible device end-product. At junctions formed between organic electron-donating and electron-accepting materials, the abrupt change in the dielectric properties can strongly perturb the density of states of the OPV. This can substantially alter the driving force for charge transfer between these materials. Electronic Sum Frequency Generation (ESFG), owing to its inherent interfacial sensitivity, is ideally suited to probe buried interfaces. Here, we report the ESFG spectra of Copper Phthalocyanine (CuPc) films, deposited on SiO2 measured for both reflection and transmission geometries. Three peaks are observed that roughly correlate with resonances that comprise CuPc's Q-band absorption but display slight shifts and amplitude changes with respect to CuPc's bulk absorption spectrum. Experimental results are compared with calculations based on a thin film interference model that accounts for ESFG emitted from both the CuPc:Air and CuPc:SiO2 interface as well as contributions to the signal from higher order source terms from the bulk. The model reveals a difference in the density of states between the two interfaces and suggests that by combining experimental transmission and reflection data it is possible to separate bulk and interfacial contributions to ESFG spectra.

  11. Environmental factors regulating soil organic matter chlorination

    Science.gov (United States)

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

    2016-04-01

    Natural chlorination of organic matter is common in soils. Despite the widespread abundance of soil chlorinated soil organic matter (SOM), frequently exceeding soil chloride abundance in surface soils, and a common ability of microorganisms to produce chlorinated SOM, we lack fundamental knowledge about dominating processes and organisms responsible for the chlorination. To take one step towards resolving the terrestrial chlorine (Cl) puzzle, this study aims to analyse how environmental factors influence chlorination of SOM. Four factors were chosen for this study: soil moisture (W), nitrogen (N), chloride (Cl) and organic matter quality (C). These factors are all known to be important for soil processes. Laboratory incubations with 36Cl as a Cl tracer were performed in a two soil incubation experiments. It was found that addition of chloride and nitrogen seem to hamper the chlorination. For the C treatment, on the other hand, the results show that chlorination is enhanced by increased availability of labile organic matter (glucose and maltose). Even higher chlorination was observed when nitrogen and water were added in combination with labile organic matter. The effect that more labile organic matter strongly stimulated the chlorination rates was confirmed by the second separate experiment. These results indicate that chlorination was not primarily a way to cut refractory organic matter into digestible molecules, representing one previous hypothesis, but is related with microbial metabolism in other ways that will be further discussed in our presentation.

  12. Supercritical Carbon Dioxide Extraction of Organic Matter from Petroleum Source Rocks and Its Implications

    Institute of Scientific and Technical Information of China (English)

    沈忠民; 周光甲; 等

    1996-01-01

    Organic matter was experimentally extracted by supercritical fluids(CO2+1% isopropanol)from petroleum source rocks of different thermo-maturities at different buried depths in the same stratigraphic unit in the Dongying Basin.The results show that supercritical fluid extraction(SFE)is more effective than Soxhlet extraction(SE),with higher amounts and greater varieties of hydrocarbons and soluble organic matter becoming extractive.The supercritical CO2 extraction is therefore considered more valuable in evaluation of petroleum source rocks and oil resources,particularly those of immature types.

  13. A Novel Type of Oil—generating Organic Matter —Crystal—enclosed Organic Matter

    Institute of Scientific and Technical Information of China (English)

    周中毅; 裴存民; 等

    1992-01-01

    The comparative study of organic matter in carbonate rocks and argillaceous rocks from the same horizon indicates that the organic thermal maturities of carbonate rocks are much lower than those of argillaceous rocks .Ana extensive analysis of extracted and inclused organic matter from the same sample shows that inclused organic matter is different from extracted organic matter,and the thermal maturity of the former is usually lower than that of the latter in terms of biomarker structural parameters.It seems that carbonate mineras could preserve organic matter and retard organic maturation.The inclused organic matter,abundant in most carbonate rocks,will be released from minerals and transformed into oil and gas during the high-thermal maturity stage.

  14. Physicochemical characterization of organic matter during co ...

    African Journals Online (AJOL)

    TCHEGUENI

    Key words: Shea-nut cake, composting, organic matter, goat manure. ... analysis. All analyses were performed on samples taken at the beginning, after 30, 90 and 180 days of ..... Maturity assessment of composted olive mill wastes using UV.

  15. Organic matter and soil moisture content and double cropping with organic matter sourceplants

    Directory of Open Access Journals (Sweden)

    John Bako Baon

    2005-05-01

    Full Text Available Double cropping of coffee with organic matter source plants is thought to increase organic matter content of soil. This study examined the effect of double cropping of coffee and organic matter source plants on soil organic matter content and yield of coffee plants. Arabica coffee trees in Andungsari Experimental Station (Bondowoso district, 1400 m asl. and climate type C; and Robusta coffee trees in Sumberasin Experimental Station (Malang district, 550 m asl. and climate type C, were used as experimental sites of this study which lasted for five years. Organic matter source plants consisted of some species that can be routinedly pruned and surface applied to coffee soil, and other creeping species that not being pruned, however the organic matter source derived from their fallen leaves. Application of farm manure and control (neither organic matter source plants nor farm yard manure were used as comparison treatments. Results indicate that Ramayana (Cassia spectabilis had vigorus growth resulting in greater biomass production compared to lamtoro (Leucaena leucocephala, mogania (Moghania macrophylla and even kaliandra (Calyandra calothyrsus which produced greater biomass among organic matter source plants grown in Arabica coffee farming. Double cropping of coffee with organic matter source plants did not affect soil organic matter content of Arabica and Robusta coffee farmings, though farm yard manure application increased soil organic matter content and soil bulk density, especially of Robusta coffee farm. Soil moisture content examined in dry season was not affected by double cropping. In contrary, Robusta coffee farm applied with farm yard manure had higher soil moisture content. At Arabica coffee farm, double cropping did not influence green coffee yield, on the other hand Ramayana reduced green coffee yield of Robusta coffee while farm yard manure increased the yield.Keywords : Coffeea arabica, Coffeea canephora, organic matter, soil

  16. Soil organic matter in the Netherlands

    NARCIS (Netherlands)

    Conijn, J.G.; Lesschen, J.P.

    2015-01-01

    Soil organic matter (SOM) and especially decreasing SOM are since many decades on the agenda of different stakeholders due to the importance of SOM for various issues ranging from local crop profitability to global climate change. Globally large amounts of organic carbon are stored in the soil and

  17. Sorption of Organic Compounds in Soil Organic Matter

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Soil organic matter (SOM)is the predominant component for sorption of hydrophobic organic compouds in soil and sorption by SOM ultimately affects chemical fate and availability in soil ,and the degree of remedia tion success of contaminated soils. This paper summarizes the latest development on sorption of organic com pounds in soil (natural) organic matter, addresses four sorption mechanisms: surface adsorption, solid - phase partitioning,dual-mode sorption,and fixed-pore sorption model ,and presents future research directions as well.

  18. Priming of Native Soil Organic Matter by Pyrogenic Organic Matter

    Science.gov (United States)

    DeCiucies, S.; Lehmann, J.; Woolf, D.; Whitman, T.

    2016-12-01

    Within the global carbon (C) cycle, soil C makes up a critical and active pool. Pyrogenic C, (PyC) or black C, contributes to this pool, and has been shown to change the turnover rate of the non-pyrogenic soil organic carbon (nSOC) associated with it. This change in rate of mineralization is referred to as priming, which can be negative or positive. There are many possible mechanisms that may be causing this priming effect, both biological and chemical. This study employs incubation experiments to identify and parse these potential mechanisms, focusing on negative priming mechanisms which may have importance in global carbon storage and carbon cycling models. Continuous respiration measurements of soil/char and soil/biomass incubations using isotopically labeled biomass (13C and 15N) indicate that priming interactions are more significant in soils with higher carbon contents, and that higher temperature chars induce more negative priming over time. Current incubations are exploring the effects of chars pyrolyzed at different temperatures, chars extracted of DOC versus non-extracted, soils with differing carbon contents, and the effects of pH and nutrient adjusting incubations. We will continue to examine the contribution of the different mechanisms by isolating variables such as nutrient addition, soil texture, char application rate, and mineral availability. We anticipate that sorption on PyOM surfaces are important in nSOM stabilization and will continue to study these effects using highly labeled substrates and nano secondary ion mass spectrometry (nano-SIMS).

  19. Sedimentary environments of organic matter from Middle Permian source rocks in northern Xinjiang,China

    Institute of Scientific and Technical Information of China (English)

    MIAO Jianyu; KOU Hansheng; ZHOU Lifa; HAN Zhongyuan

    2006-01-01

    A systematic analysis of the inorganic and organic geochemistry of Middle Permian source rocks comprising carbonate rocks and mudstones was carried out, with samples collected from the outcrop and bore of the Junggar, Turpan and Ili basins in northern Xinjiang. This study confirmed that sedimentary parameters for an ancient water body, such as inorganic geochemistry and paleosalinity, have a close relation to the organic matter of source rocks. It is also disclosed that phytane predominance in the source rocks is mainly due to a reducing environment. Biomarkers, such as gammacerane and β-carotene, in the samples reflect a specific salinity in the sedimentary environments. Sedimentary zones with a strong reducing environment are more likely to produce deposits of primary organic matter, which will be buried and preserved contemporarily. Consequently, the source rocks are generally high in organic content and better in organic type than ordinary ones, and vice versa.

  20. Organic matter stocks in temperate forest soil

    OpenAIRE

    Schöning, Ingo

    2006-01-01

    In temperate forests, more than 60% of the total carbon reserves are located in forest floor and mineral soil. The main objectives of this study were (1) to investigate the composition and radiocarbon age of organic matter (OM) pools of different stability in mineral soils, (2) to identify associations between iron oxides and specific carbon species, and (3) to analyse the small scale spatial variability of soil organic carbon (SOC) stocks. Composition, radiocarbon age and associations betwee...

  1. Soil architecture and distribution of organic matter

    NARCIS (Netherlands)

    Kooistra, M.J.; Noordwijk, van M.

    1996-01-01

    The biological component of soil structure varies greatly in quality and quantity, occurs on different scales, and varies throughout the year. It is far less predictable than the physical part and human impact. The occurrence and distribution of organic matter depends on several processes, related t

  2. Lability of Secondary Organic Particulate Matter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pengfei; Li, Yong Jie; Wang, Yan; Giles, Mary K.; Zaveri, Rahul A.; Bertram, Allan K.; Martin, Scot T.

    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, 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.

  3. Analysis of Organic matter from cloud particles

    Science.gov (United States)

    Bank, Shelton; Castillo, Raymond

    1987-03-01

    Organic matter collected from filtration of two separate cloud events was analysed by Fourier Transform Infrared Spectroscopy. Particles collected from different size filters were separated by color and each type of particle gave rise to a characteristic spectrum. The major constituents were identified as complex proteins and cellulose. Additionally, some degraded material (likely protein) and an unidentified orange-brown material were present. Finally some trace components were identified as wax, oil, silicon oil, polyvinyl chloride, calcium carbonate, clay, sand and polyethylene.

  4. Organic matter matters for ice nuclei of agricultural soil origin

    Directory of Open Access Journals (Sweden)

    Y. Tobo

    2014-04-01

    Full Text Available Heterogeneous ice nucleation is a~crucial process for forming ice-containing clouds and subsequent ice-induced precipitation. The importance for ice nucleation of airborne desert soil dusts composed predominantly of minerals is relatively well understood. On the other hand, the potential influence of agricultural soil dusts on ice nucleation has been poorly recognized, despite recent estimates that they may account for up to ∼25% of the global atmospheric dust load. We have conducted freezing experiments with various dusts, including agricultural soil dusts derived from the largest dust source region in North America. Here we show evidence for the significant role of soil organic matter (SOM in particles acting as ice nuclei (IN under mixed-phase cloud conditions. We find that the ice nucleating ability of the agricultural soil dusts is similar to that of desert soil dusts, but is reduced to almost the same level as that of clay minerals (e.g., kaolinite after either H2O2 digestion or dry heating to 300 °C. In addition, based on chemical composition analysis, we show that organic-rich particles are more important than mineral particles for the ice nucleating ability of the agricultural soil dusts at temperatures warmer than about −36 °C. Finally, we suggest that such organic-rich particles of agricultural origin (namely, SOM particles may contribute significantly to the ubiquity of organic-rich IN in the global atmosphere.

  5. Peer reviewed: Characterizing aquatic dissolved organic matter

    Science.gov (United States)

    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.

  6. Organic matter degradation in Chilean sediments - following nature's own degradation experiment

    DEFF Research Database (Denmark)

    Langerhuus, Alice Thoft; Niggemann, Jutta; Lomstein, Bente Aagaard

    .000 year old sediments. Since the microbial activity in the deep sediments is very low, it is still not possible to measure it directly. Following nature’s own experiment back in time will provide us with new insights about the microbial activity in the deeply buried sediments. Poster presentation Session...... in length, respectively. The objective of this study was to assess the degradability of the organic matter from the sediment surface to the deep sediments. This was done by analysing amino acids (both L- and D-isomers) and amino sugars in the sediment cores, covering a timescale of 15.000 years. Diagenetic...

  7. Repeated application of organic waste affects soil organic matter composition

    DEFF Research Database (Denmark)

    Peltre, Clément; Gregorich, Edward G.; Bruun, Sander

    2017-01-01

    of different types of carbon compounds in soil. The objective of this study was to identify and characterise changes in soil organic matter (SOM) composition after repeated applications of organic waste. Soil from the CRUCIAL field experiment in Denmark was sampled after 12 years of annual application...... that there was accumulation in soil of different C compounds for the different types of applied organic waste, which appeared to be related to the degree to which microbial activity was stimulated and the type of microbial communities applied with the wastes or associated with the decomposition of applied wastes...

  8. Clay-associated organic matter in kaolinitic and smectitic soils

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.

    2002-01-01

    The primary source of soil organic matter is plant debris of all kinds, such as dead roots, leaves and branches that enter into the soil and are then biologically decomposed at variable rates. Organic matter has many different important functions on a local and global scale. Soil organic matter is a

  9. Clay-associated organic matter in kaolinitic and smectitic soils

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.

    2002-01-01

    The primary source of soil organic matter is plant debris of all kinds, such as dead roots, leaves and branches that enter into the soil and are then biologically decomposed at variable rates. Organic matter has many different important functions on a local and global scale. Soil organic matter is a

  10. Abiotic Bromination of Soil Organic Matter.

    Science.gov (United States)

    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. Roles of epi-anecic taxa of earthworms in the organic matter recycling

    Science.gov (United States)

    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...).

  12. Mapping Soil Organic Matter with Hyperspectral Imaging

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  14. Stability of Ferrihydrite and Organic Matter in Ferrihydrite-Organic Matter Associations

    Science.gov (United States)

    Eusterhues, K.; Totsche, K. U.

    2015-12-01

    Iron oxides can bind particularly large amounts of organic matter (OM) and seem to be an important control on OM storage in many soils. To better understand the interactions between Fe oxides and OM, we produced ferrihydrite-OM associations by adsorption and coprecipitation in laboratory experiments. Because ferrihydrites are often formed in OM-rich solutions, we assume that coprecipitation is a common process in nature. In contrast to adsorption on pre-existing ferrihydrite surfaces, coprecipitation involves adsorption, occlusion (physical entrapment of OM), formation of Fe-OM complexes, and poisoning of ferrihydrite growth. The reactivity of coprecipitates may therefore differ from ferriydrites with adsorbed OM. Incubation experiments with an inoculum extracted from a Podzol forest-floor were carried out to quantify the mineralization of the adsorbed and coprecipitated organic matter. These experiments showed that the association with ferrihydrite stabilized the associated organic matter, but that differences in the degradability of adsorbed and coprecipitated organic matter were small. We therefore conclude that coprecipitation does not lead to a significant formation of microbial inaccessible organic matter domains. Microbial reduction experiments were performed using Geobacter bremensis. We observed that increasing amounts of associated OM led to decreasing initial reaction rates and a decreasing degree of dissolution. Reduction of coprecipitated ferrihydrites was faster than reduction of ferrihydrites with adsorbed OM. Our data demonstrate that the association with ferrihydrite can effectively stabilize labile polysaccharides. Vice versa, these polysaccharides may protect ferrihydrite from reduction by Geobacter-like bacteria. However, a challenge for future studies will be to link formation and degradation of mineral-organic associations to natural porous systems, that is, to the complex interplay of mass transport and microbial distribution in the

  15. Characteristics of natural organic matter affect sorption of organic contaminants

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Several soil samples were used to study how the characteristics of natural organic matter (NOM) affect sorption of organic compounds. These soils contains different amounts and types of NOM. Aromaticity of NOM (percentage of aromatic carbons) was determined from solid-state CPMAS 13C NMR spectra and the soil effective polarity was computed from the equation developed by Xing et al. Naphthalene was used to examine the sorption characteristics of NOM. Both aromaticity and polarity of NOM strongly affected sorption of naphthalene. Old NOM showed higher affinity than that in the surface, young soils. Sorption increased with increasing aromaticity and decreasing polarity. Thus, the sorption coefficients of organic contaminants cannot be accurately predicted without some consideration of NOM characteristics.

  16. Biogeochemical Processes That Produce Dissolved Organic Matter From Wheat Straw

    Science.gov (United States)

    Wershaw, Robert L.; Rutherford, David W.; Leenheer, Jerry A.; Kennedy, Kay R.; Cox, Larry G.; Koci, Donald R.

    2003-01-01

    The chemical reactions that lead to the formation of dissolved organic matter (DOM) in natural waters are poorly understood. Studies on the formation of DOM generally are complicated because almost all DOM isolates have been derived from mixtures of plant species composed of a wide variety of different types of precursor compounds for DOM formation. This report describes a study of DOM derived mainly from bales of wheat straw that had been left in a field for several years. During this period of time, black water from the decomposing wheat straw accumulated in pools in the field. The nuclear magnetic resonance and infrared spectra of the black water DOM indicate that it is composed almost entirely of lignin and carbohydrate polymeric units. Analysis by high-performance size-exclusion chromatography with multi-angle laser-light scattering detection indicates that the number average molecular weight of the DOM is 124,000 daltons. The results presented in this report indicate that the black water DOM is composed of hemicellulose chains cross-linked to lignin oligomers. These types of structures have been shown to exist in the hemicellulose matrix of plant cell walls. The cross-linked lignin-hemicellulose complexes apparently were released from partially degraded wheat-straw cell walls with little alteration. In solution in the black water, these lignin-hemicellulose polymers fold into compact globular particles in which the nonpolar parts of the polymer form the interiors of the particles and the polar groups are on the exterior surfaces of the particles. The tightly folded, compact conformation of these particles probably renders them relatively resistant to microbial degradation. This should be especially the case for the aromatic lignin structures that will be buried in the interiors of the particles.

  17. Effect of Organic Matter on Manganese Solubility

    Directory of Open Access Journals (Sweden)

    Emilene Andrade

    2002-03-01

    Full Text Available The objective of this study was to re-evaluate some aspects of the relative importance of organic matter on Mn solubility in acid soil conditions. Field study showed that black oats, oil seed radish, elephant grass, lupin, leucaena, and coffee leaves serving as mulch decreased Mn solubility as compared with bare soil. The decrease in Mn solubility with plant mulch was related to increase in soil moisture content. Laboratory study showed that increasing temperature from 25 to 100ºC increased Mn solubility and total soil organic carbon was little changed; from 150 to 200ºC increased both Mn solubility and organic carbon oxidation, and up to 300ºC decreased Mn solubility and stoped organic carbon oxidation . Aluminum solubility always increased with increasing temperature. Organic matter exerted a control in both Mn and Al solubilities in acid soils.O estudo foi conduzido com objetivo de reavaliar alguns aspectos da importância relativa da matéria orgânica na solubilidade do Mn em solos ácidos. Em condição de campo cobertura morta com resíduos de aveia preta, nabo forrageiro, napier, tremoço, leucena e folhas de café diminuíram a solubilidade de Mn quando comparada com o solo descoberto. A redução na solubilidade do Mn em solo coberto com resíduos vegetais foi relacionada com o teor de umidade do solo. Estudos de laboratório demonstraram que o aumento da temperatura de 25 para 100ºC aumentou a solubilidade do Mn com pouca alteração no teor de carbono do solo; de 150 a 200ºC aumentou ambas a solubilidade do Mn e a oxidação do carbono orgânico e acima de 300ºC diminuiu a solubilidade do Mn e completou a oxidação do carbono orgânico. A solubilidade do Al sempre aumentou com a elevação da temperatura. A matéria orgânica influenciou diretamente a solubilidade do Mn e do Al.

  18. Starting life requires more than organic matter

    Science.gov (United States)

    Pascal, R.

    2015-10-01

    A physicochemical approach is proposed to study requirements for the origin of life in agreement with developments made in Systems Chemistry for several decades. Emphasis is made on the occurrence of environments generating abiotic chemical systems making more of themselves under far from equilibrium conditions. It follows that the presence of organic matter is only one of the components needed for the process of chemical evolution leading to life. The presence of an energy source with a potential equivalent to that of visible light is needed to render the activation step kinetically irreversible and the reproduction loop a unidirectional flux of reactants. This condition is required in order that reproduction follows an exponential law and dynamic kinetic stability governs the evolution toward the selection of improved variants. According to these views, no fundamental difference can be found between the chemical and biological stages of evolution.

  19. Structure of the Buried Metal-Molecule Interface in Organic Thin Film Devices

    DEFF Research Database (Denmark)

    Hansen, Christian Rein; Sørensen, Thomas Just; Glyvradal, Magni

    2009-01-01

    By use of specular X-ray reflectivity (XR) the structure of a metal-covered organic thin film device is measured with angstrom resolution. The model system is a Langmuir-Blodgett (LB) film, sandwiched between a silicon substrate and a top electrode consisting of 25 Å titanium and 100 Å aluminum...

  20. Sedimentation, distribution and diagenesis of organic matter in a recent carbonate environment, Abu Dhabi, U. A. E

    Energy Technology Data Exchange (ETDEWEB)

    Kenig, F.; Huc, A.Y. (Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)); Purser, B.H. (Paris-11 Univ., 91 - Orsay (France). Lab. de Petrologie Sedimentaire et Paleontologie); Oudin, J.-L. (Total CFP, 33 - Pessac (France))

    1990-01-01

    In the modern hypersaline carbonate lagoon and sabkha sedimentary environments of Abu Dhabi (United Arab Emirates), three types of organic matter originate respectively from microbial mat, Avicennia mangrove, and Halodule lagoonal seagrass. The study of recent sedimentary processes and cross sections through the sabkha sediments leads to the definition of organo-sedimentary facies based on geochemical and sedimentological criteria. This permits the construction of an organo-sedimentary sequence which expresses the Holocene sedimentary record involving a transgressive and a regressive sequence. The various organic facies occur in both sequences. Heterogeneity within the individual organic facies reflects several factors, including sedimentation dynamics, mineral matrix, oxidation and reduction, and selective organic and mineral diagenesis. These parameters are discussed in terms of depositional environment and location within the organo-sedimentary sequence. Changes in distribution, quantity, and preservation potential of the buried organic matter are discussed in terms of sea level changes and sedimentary accretion rates. (10 figures, 32 references) (Author)

  1. Investigating Photosensitized Properties of Natural Organic Matter and Effluent Organic Matter

    KAUST Repository

    Niu, Xi-Zhi

    2013-05-01

    The photosensitized processes significantly enhance photolysis of various chemicals in the aqueous system with dissolved organic matter (DOM) as sensitizer. The excitation of chromophores on the DOM molecule further generates reactive species as triplet states DOM, singlet oxygen, hydroxyl radical, carbonate radical etc. We investigated the photosensitization properties of Beaufort Fulvic Acid, Suwannee River Fulvic Acid, South Platte River Fulvic Acid, and Jeddah wastewater treatment plant effluent organic matter with a sunlight simulator. DOM photochemical properties were characterized by observing their performances in 3DOM*, singlet oxygen, hydroxyl radical production with indirect probing protocols. Sensitized degradation of 0.1 μM and 0.02 μM 2, 4, 6- Trimethylphenol exhibited higher pseudo-first-order rate constant than that of 10 μM. Pre-irradiated DOMs were found to be depressed in photochemical properties. Photolysis of 5 different contaminants: ibuprofen, bisphenol A, acetaminophen, cimetidine, and caffeine were found to be enhanced in the presence of sensitizers. The possible reaction pathways were revealed. Long time irradiance induced change in contaminants degradation kinetics in some DOM solutions, which was proposed to be due to the irradiation initiated indirect transformation of DOMs. Key Words: Photolysis Dissolved Organic Matter, Triplet State DOM, Singlet Oxygen, Hydroxyl Radical, Contaminants Degradation.

  2. Long-term controls on the composition of particulate organic carbon buried offshore from the Waipaoa River, North Island, New Zealand

    Science.gov (United States)

    Leithold, E. L.; Blair, N. E.; Childress, L. B.; Brulet, B.

    2009-12-01

    In the Waipaoa watershed on the North Island of New Zealand, as in many small mountainous watersheds around the world, high sediment yields are accommodated by the weathering and mass wasting of bedrock as well as of its mantle of soil and vegetation. Investigation of both the contemporary Waipaoa system and the sedimentary record preserved in adjacent marine depocenters reveals that these three sources of sediment have also been the primary sources of riverine POC throughout the watershed’s Holocene history, but that their relative roles have varied as a function of environmental perturbations. Mass balance calculations using stable and radiogenic carbon isotopic ratios of organic matter associated with both bulk sediments and clay-sized isolates point to a large and persistent contribution of kerogen to POC in the Waipaoa system. This material has accumulated on the continental margin along with terrestrial plant-derived OC, much of which apparently had a short residence time in the watershed. The accelerated contribution of OC-poor volcanic tephra to the Waipaoa sediment load beginning about 4000 years ago led to dilution of both the kerogen and plant fraction, and ultimately to enhanced marine OC burial on the shelf via production of new mineral surface area and sorption from porewaters. Beginning around 700 years BP, anthropogenic influences have left their mark on the watershed and offshore record, including the introduction of a pulse of fine-grained charcoal from biomass burning. Deforestation of the headwaters has led to more widespread shallow landsliding and to the development of large gully complexes incised into tectonically crushed mudstones. The increased kerogen flux due to chronic gully erosion is apparent in the offshore record, but its impact on the composition and age of OC buried on the continental shelf is muted compared to the increase in riverine sediment discharge and sediment accumulation observed on the margin.

  3. Resins and asphaltenes: evolution as a function of organic-matter type and burial

    Energy Technology Data Exchange (ETDEWEB)

    Castex, H. (Institut Francais du Petrole, 92 - Rueil-Malmaison (France))

    Elemental analysis was used to investigate 151 resins and 175 asphaltenes extracted from rocks from several basins. It was shown that: resins have higher mean carbon and hydrogen values as well as a lower C/H ratio than asphaltenes. Resins thus have a more aliphatic and or more alicyclic structure. On the other hand, asphaltenes contain more sulfur, oxygen and nitrogen. Different types of organic matter are revealed by an H/C, O/C diagram. Their chemical evolution with burial is characterized by a decrease in hydrogen, oxygen and sulfur contents. Proton nuclear magnetic resonance (NMR) and infrared spectroscopy (IRS) were used to follow the structural evolution of resins and asphaltenes coming from different types of organic matter (algal, marine and terrestrial) buried at increasing depths. NMR can be used to compute several structural parameters such as Fsub(A) aromaticity and the degree of sigma substitution of the aromatic system. These data were completed by infrared spectroscopy. Variations in the intensity of bands: decrease of aliphatic C-H and of C = O fonctions; increase of aromatic C-H and C = C are related to both the type of organic matter and its catagenesis.

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

    Science.gov (United States)

    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...

  5. Seasonal distribution of organic matter in mangrove environment of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Jagtap, T.G.

    Water and sediments were studied for the distribution of suspended matter, organic carbon and nitrogen Suspended matter ranged from 3-373 mg.l-1 while particulate organic carbon (POC) from 0.03-9.94 mg.l-1 POC value showed significant correlation...

  6. Deep ploughing increases agricultural soil organic matter stocks.

    Science.gov (United States)

    Alcántara, Viridiana; Don, Axel; Well, Reinhard; Nieder, Rolf

    2016-08-01

    Subsoils play an important role within the global C cycle, since they have high soil organic carbon (SOC) storage capacity due to generally low SOC concentrations. However, measures for enhancing SOC storage commonly focus on topsoils. This study assessed the long-term storage and stability of SOC in topsoils buried in arable subsoils by deep ploughing, a globally applied method for breaking up hard pans and improving soil structure to optimize crop growing conditions. One effect of deep ploughing is translocation of SOC formed near the surface into the subsoil, with concomitant mixing of SOC-poor subsoil material into the 'new' topsoil. Deep-ploughed croplands represent unique long-term in situ incubations of SOC-rich material in subsoils. In this study, we sampled five loamy and five sandy soils that were ploughed to 55-90 cm depth 35-50 years ago. Adjacent, similarly managed but conventionally ploughed subplots were sampled as reference. The deep-ploughed soils contained on average 42 ± 13% more SOC than the reference subplots. On average, 45 years after deep ploughing, the 'new' topsoil still contained 15% less SOC than the reference topsoil, indicating long-term SOC accumulation potential in the topsoil. In vitro incubation experiments on the buried sandy soils revealed 63 ± 6% lower potential SOC mineralisation rates and also 67 ± 2% lower SOC mineralisation per unit SOC in the buried topsoils than in the reference topsoils. Wider C/N ratio in the buried sandy topsoils than in the reference topsoils indicates that deep ploughing preserved SOC. The SOC mineralisation per unit SOC in the buried loamy topsoils was not significantly different from that in the reference topsoils. However, 56 ± 4% of the initial SOC was preserved in the buried topsoils. It can be concluded that deep ploughing contributes to SOC sequestration by enlarging the storage space for SOC-rich material.

  7. Dissolved Organic Matter and Emerging Contaminants in Urban Stream Ecosystems

    Science.gov (United States)

    Kaushal, S. S.; Findlay, S.; Groffman, P.; Belt, K.; Delaney, K.; Sides, A.; Walbridge, M.; Mayer, P.

    2009-05-01

    We investigated the effects of urbanization on the sources, bioavailability and forms of natural and anthropogenic organic matter found in streams located in Maryland, U.S.A. We found that the abundance, biaoavailability, and enzymatic breakdown of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved organic phosphorus (DOP) increased in streams with increasing watershed urbanization suggesting that organic nutrients may represent a growing form of nutrient loading to coastal waters associated with land use change. Organic carbon, nitrogen, and phosphorus in urban streams were elevated several-fold compared to forest and agricultural streams. Enzymatic activities of stream microbes in organic matter decomposition were also significantly altered across watershed land use. Chemical characterization suggested that organic matter in urban streams originated from a variety of sources including terrestrial, sewage, and in-stream transformation. In addition, a characterization of emerging organic contaminants (polyaromatic cyclic hydrocarbons, organochlorine pesticides, and polybrominated diphenyl ether flame retardents), showed that organic contaminants and dissolved organic matter increase with watershed urbanization and fluctuate substantially with changing climatic conditions. Elucidating the emerging influence of urbanization on sources, transport, and in-stream transformation of organic nutrients and contaminants will be critical in unraveling the changing role of organic matter in urban degraded and restored stream ecosystems.

  8. Methods for Determining Organic Matter and Colour in Water

    Directory of Open Access Journals (Sweden)

    Ramunė Albrektienė

    2011-02-01

    Full Text Available The article examines different methods for determining organic matter and colour in water. Most of organic compounds in water have a humic substance. These substances frequently form complexes with iron. Humic matter gives water a yellow-brownish colour. Water filtration through conventional sand filters does not remove colour and organic compounds, and therefore complicated water treatment methods shall be applied. The methods utilized for organic matter determination in water included research on total organic carbon, permanganate index and the bichromate number of UV absorption of 254 nm wave length. The obtained results showed the greatest dependence between water colour and permanganate index. However, UV adsorption could be used for organic matter determination during the operation of a water treatment plant and the start-up of plants as easy and fast methods.Article in Lithuanian

  9. Changes in River Organic Matter Through Time.

    Science.gov (United States)

    Hudson, N.; Baker, A.; Ward, D.

    2006-12-01

    fluorescence, as an increase in pH was also observed in these samples. This work illustrates the dynamic character of river organic matter within a timescale and under conditions that are representative of the natural system.

  10. Variations in organic matter bound in fluffy layer suspended matter from the Pomeranian Bay (Baltic Sea

    Directory of Open Access Journals (Sweden)

    Ksenia Pazdro

    2001-12-01

    Full Text Available Fluffy layer suspended matter (FLSM and surface sediment samples from the Pomeranian Bay were examined for fatty acid, lipid and organic matter contents. FLSM is a several-centimetre-thick layer of fairly concentrated particulate matter lying on the sea floor significantly affecting the flux of matter to depositional basins. Analyses of fatty acids were used to establish sources and decomposition rates of labile organic matter along a transect from the shallow, highly dynamic, Odra estuary to the Arkona Basin, a deep, low energy, depositional area. In FLSM and sediments respectively, the ranges of organic matter contents were 4.0-25.0% and 5.1-23.0%, those of lipids 0.1-5.4% and 0.30-1.67%, and those of fatty acids 50-991 µg g-1 dry wt. and 100-546 µg g-1 dry wt. In shallow waters, the contents of these compounds are very variable, mirroring variations in biological activity and hydrological conditions. The high percentage of polyunsaturated fatty acids in shallow areas indicates the presence of fresh, undegraded, labile organic matter of autochthonous origin. Fatty acids, the most labile components, are transported as suspended matter attached to minerals and finally accumulated in the depositional area in the form of condensed organic macromolecules. The intensity of bacterial decomposition of organic matter in this system is reflected in the high percentage of branched fatty acids. The low fatty acid content in the organic matter is attributed to the high rate of decomposition of the labile organic matter. No linear correlation was found between the contents of fatty acids and lipids.

  11. Degradation of natural organic matter: A thermodynamic analysis

    Science.gov (United States)

    LaRowe, Douglas E.; Van Cappellen, Philippe

    2011-04-01

    The oxidative degradation of organic matter is a key process in the biogeochemical functioning of the earth system. Quantitative models of organic matter degradation are therefore essential for understanding the chemical state and evolution of the Earth's near-surface environment, and to forecast the biogeochemical consequences of ongoing regional and global change. The complex nature of biologically produced organic matter represents a major obstacle to the development of such models, however. Here, we compare the energetics of the oxidative degradation of a large number of naturally occurring organic compounds. By relating the Gibbs energies of half reactions describing the complete mineralization of the compounds to their average nominal carbon oxidation state, it becomes possible to estimate the energetic potential of the compounds based on major element (C, H, N, O, P, S) ratios. The new energetic description of organic matter can be combined with bioenergetic theory to rationalize observed patterns in the decomposition of natural organic matter. For example, the persistence of cell membrane derived compounds and complex organics in anoxic settings is consistent with their limited catabolic potential under these environmental conditions. The proposed approach opens the way to include the thermodynamic properties of organic compounds in kinetic models of organic matter degradation.

  12. Is resistant soil organic matter more sensitive to temperature than the labile organic matter?

    Directory of Open Access Journals (Sweden)

    C. Fang

    2006-01-01

    Full Text Available A recent paper by Knorr et al. (2005a suggested that the decomposition of resistant soil organic matter is more temperature sensitive than labile organic matter. In Knorr et al.'s (2005a model, the reference decay rate was presumed to be same for all pools of soil carbon. We refit Knorr et al.'s (2005a model but allow both the activation energy and the reference decay rate to vary among soil C pools. Under these conditions, a similar fit to measured data can be obtained without invoking the assumption that the resistant C pool is more temperature sensitive than the labile pool. Other published evidence does not unequivocally support Knorr et al.'s (2005a hypothesis of increased temperature sensitivity of resistant pools of soil carbon. Because of the lack of experimental data, Knorr et al.'s (2005a conclusion that the decomposition of the resistant SOM is more temperature sensitive than the labile pool is premature.

  13. Particulate organic matter in the sea: the composition conundrum.

    Science.gov (United States)

    Lee, Cindy; Wakeham, Stuart; Arnosti, Carol

    2004-12-01

    As organic matter produced in the euphotic zone of the ocean sinks through the mesopelagic zone, its composition changes from one that is easily characterized by standard chromatographic techniques to one that is not. The material not identified at the molecular level is called "uncharacterized". Several processes account for this transformation of organic matter: aggregation/disaggregation of particles resulting in incorporation of older and more degraded material; recombination of organic compounds into geomacromolecules; and selective preservation of specific biomacromolecules. Furthermore, microbial activities may introduce new cell wall or other biomass material that is not easily characterized, or they may produce such material as a metabolic product. In addition, black carbon produced by combustion processes may compose a fraction of the uncharacterized organic matter, as it is not analyzed in standard biochemical techniques. Despite these poorly-defined compositional changes that hinder chemical identification, the vast majority of organic matter in sinking particles remains accessible to and is ultimately remineralized by marine microbes.

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

    Science.gov (United States)

    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.

  15. Pyrogenic organic matter can alter microbial communication

    Science.gov (United States)

    Masiello, Caroline; Gao, Xiaodong; Cheng, Hsiao-Ying; Silberg, Jonathan

    2016-04-01

    Soil microbes communicate with each other to manage a large range of processes that occur more efficiently when microbes are able to act simultaneously. This coordination occurs through the continuous production of signaling compounds that are easily diffused into and out of cells. As the number of microbes in a localized environment increases, the internal cellular concentration of these signaling compounds increases, and when a threshold concentration is reached, gene expression shifts, leading to altered (and coordinated) microbial behaviors. Many of these coordinated behaviors have biogeochemically important outcomes. For example, methanogenesis, denitrification, biofilm formation, and the development of plant-rhizobial symbioses are all regulated by a simple class of cell-cell signaling molecules known as acyl homoserine lactones (AHLs). Pyrogenic organic matter in soils can act to disrupt microbial communication through multiple pathways. In the case of AHLs, charcoal's very high surface area can sorb these signaling compounds, preventing microbes from detecting each others' presence (Masiello et al., 2014). In addition, the lactone ring in AHLs is vulnerable to pH increases accompanying PyOM inputs, with soil pH values higher than 7-8 leading to ring opening and compound destabilization. Different microbes use different classes of signaling compounds, and not all microbial signaling compounds are pH-vulnerable. This implies that PyOM-driven pH increases may trigger differential outcomes for Gram negative bacteria vs fungi, for example. A charcoal-driven reduction in microbes' ability to detect cell-cell communication compounds may lead to a shift in the ability of microbes to participate in key steps of C and N cycling. For example, an increase in an archaeon-specific AHL has been shown to lead to a cascade of metabolic processes that eventually results in the upregulation of CH4 production (Zhang et al., 2012). Alterations in similar AHL compounds leads to

  16. Soil organic matter in the Moscow State University botanical garden on the Vorob'evy Hills

    Science.gov (United States)

    Rozanova, M. S.; Prokof'eva, T. V.; Lysak, L. V.; Rakhleeva, A. A.

    2016-09-01

    Humification conditions and humus status parameters in arboretum soils of the Moscow State University botanical garden on the Vorob'evy Hills have been studied. Although microbiological activity is reduced, the warm and mild climate in the city, the eutrophication of soils (due to atmospheric fallouts and dissolution of construction waste inclusions), the retention of plant waste on the soil surface, and the presence of abundant primary destructors (mesofauna) have resulted in the formation of organic matter with specific characteristics. During the 60 years that have elapsed since the arboretum establishment, soils with a high content (up to 10-14%) of humate humus (CHA/CFA > 1) characterized by a higher degree of humification than in the control soils under herbaceous vegetation have been developed in the area. Large reserves of organic carbon have been noted not only in the upper 30-cm-thick soil layer, but also in the 1-m-thick layer due to organic matter of buried and technogenic horizons.

  17. Microbial metabolism mediates interactions between dissolved organic matter and clay minerals in streamwater

    Science.gov (United States)

    Hunter, W. R.; Battin, T. J.

    2016-08-01

    Sorption of organic molecules to mineral surfaces is an important control upon the aquatic carbon (C) cycle. Organo-mineral interactions are known to regulate the transport and burial of C within inland waters, yet the mechanisms that underlie these processes are poorly constrained. Streamwater contains a complex and dynamic mix of dissolved organic compounds that coexists with a range of organic and inorganic particles and microorganisms. To test how microbial metabolism and organo-mineral complexation alter amino acid and organic carbon fluxes we experimented with 13C-labelled amino acids and two common clay minerals (kaolinite and montmorillonite). The addition of 13C-labelled amino acids stimulated increased microbial activity. Amino acids were preferentially mineralized by the microbial community, concomitant with the leaching of other (non-labelled) dissolved organic molecules that were removed from solution by clay-mediated processes. We propose that microbial processes mediate the formation of organo-mineral particles in streamwater, with potential implications for the biochemical composition of organic matter transported through and buried within fluvial environments.

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

    Science.gov (United States)

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

    2012-01-01

    Of the factors which control the quantity and composition of organic matter (OM) buried in marine sediments, the links between infaunal ingestion and gut passage and sediment geochemistry have received relatively little attention. This study aimed to use feeding experiments and novel isotope tracing techniques to quantify amino acid net accumulation and loss during polychaete gut passage, and to link this to patterns of selective preservation and decay in sediments. Microcosms containing either Arenicolamarina or Hediste (formerly Nereis) diversicolor were constructed from defaunated sediment and filtered estuarine water, and maintained under natural temperature and light conditions. They were fed with 13C-labelled diatoms daily for 8 days, and animals were transferred into fresh, un-labelled sediment after ∼20 days. Samples of fauna, microcosm sediment and faecal matter were collected after 8, ∼20 and ∼40 days, and analysed for their bulk isotopic signatures and 13C-labelled amino acid compositions. Bulk isotopic data showed that, consistent with their feeding modes, Hediste assimilated added 13C more quickly, and attained a higher labelling level than Arenicola. Both species retained the added 13C in their biomass even after removal from the food. A principal component analysis of 13C-labelled amino acid mole percentages showed clear differences in composition between the algae, faunal tissues, and sediment plus faecal matter. Further, the two species of polychaete showed different compositions in their tissues. The amino acids phenylalanine, valine, leucine, iso-leucine, threonine and proline showed net accumulation in polychaete tissues. Serine, methionine, lysine, aspartic and glutamic acids and tyrosine were rapidly lost through metabolism, consistent with their presence in easily digestible cell components (as opposed to cell walls which offer physical protection). All sample types (polychaete tissues, sediments and faecal matter) were enriched in

  19. Carbon cycle: Ocean dissolved organics matter

    Science.gov (United States)

    Amon, Rainer M. W.

    2016-12-01

    Large quantities of organic carbon are stored in the ocean, but its biogeochemical behaviour is elusive. Size-age-composition relations now quantify the production of tiny organic molecules as a major pathway for carbon sequestration.

  20. Supramolecular Soft Matter Applications in Materials and Organic Electronics

    CERN Document Server

    Nakanishi, Takashi

    2011-01-01

    The pivotal text that bridges the gap between fundamentals and applications of soft matter in organic electronics Covering an expanding and highly coveted subject area, Supramolecular Soft Matter enlists the services of leading researchers to help readers understand and manipulate the electronic properties of supramolecular soft materials for use in organic opto-electronic devices, such as photovoltaics and field effect transistors, some of the most desired materials for energy conservation. Rather than offering a compilation of current trends in supramolecular soft matter, this book bridges

  1. Composition and reactivity of ferrihydrite-organic matter associations

    Science.gov (United States)

    Eusterhues, Karin; Hädrich, Anke; Neidhardt, Julia; Küsel, Kirsten; Totsche, Kai

    2014-05-01

    The formation of organo-mineral associations affects many soil forming processes. On the one hand, it will influence soil organic matter composition and development, because the complex organic matter mixtures usually fractionate during their association with mineral surfaces. Whereas the associated fraction is supposed to be stabilized, the non-associated fraction remains mobile and available to degradation by microorganisms. On the other hand, the organic coating will completely change the interface properties of Fe oxides such as solubility, charge and hydrophobicity. This in turn will strongly influence their reactivity towards nutrients and pollutants, the adsorption of new organic matter, and the availability of ferric Fe towards microorganisms. To better understand such processes we produced ferrihydrite-organic matter associations by adsorption and coprecipitation in laboratory experiments. As a surrogate for dissolved soil organic matter we used the water-extractable fraction of a Podzol forest-floor layer under spruce. Sorptive fractionation of the organic matter was investigated by 13C NMR and FTIR. Relative to the original forest-floor extract, the ferrihydrite-associated OM was enriched in polysaccharides but depleted in aliphatic C and carbonyl C, especially when adsorption took place. Liquid phase incubation experiments were carried out with an inoculum extracted from the podzol forest-floor under oxic conditions at pH 4.8 to quantify the mineralization of the adsorbed and coprecipitated organic matter. These experiments showed that the association with ferrihydrite stabilized the associated organic matter, but that differences in the degradability of adsorbed and coprecipitated organic matter were small. We therefore conclude that coprecipitation does not lead to a significant formation of microbial inaccessible organic matter domains. Microbial reduction experiments were performed using Geobacter bremensis. We observed that increasing amounts of

  2. Organic Matter Responses to Radiation under Lunar Conditions

    Science.gov (United States)

    Matthewman, Richard; Crawford, Ian A.; Jones, Adrian P.; Joy, Katherine H.; Sephton, Mark A.

    2016-11-01

    Large bodies, such as the Moon, that have remained relatively unaltered for long periods of time have the potential to preserve a record of organic chemical processes from early in the history of the Solar System. A record of volatiles and impactors may be preserved in buried lunar regolith layers that have been capped by protective lava flows. Of particular interest is the possible preservation of prebiotic organic materials delivered by ejected fragments of other bodies, including those originating from the surface of early Earth. Lava flow layers would shield the underlying regolith and any carbon-bearing materials within them from most of the effects of space weathering, but the encapsulated organic materials would still be subject to irradiation before they were buried by regolith formation and capped with lava. We have performed a study to simulate the effects of solar radiation on a variety of organic materials mixed with lunar and meteorite analog substrates. A fluence of ˜3 × 1013 protons cm-2 at 4-13 MeV, intended to be representative of solar energetic particles, has little detectable effect on low-molecular-weight (≤C30) hydrocarbon structures that can be used to indicate biological activity (biomarkers) or the high-molecular-weight hydrocarbon polymer poly(styrene-co-divinylbenzene), and has little apparent effect on a selection of amino acids (≤C9). Inevitably, more lengthy durations of exposure to solar energetic particles may have more deleterious effects, and rapid burial and encapsulation will always be more favorable to organic preservation. Our data indicate that biomarker compounds that may be used to infer biological activity on their parent planet can be relatively resistant to the effects of radiation and may have a high preservation potential in paleoregolith layers on the Moon.

  3. Natural organic matter properties in Swedish agricultural streams

    Science.gov (United States)

    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.

  4. Modeling organic matter stabilization during windrow composting of livestock effluents.

    Science.gov (United States)

    Oudart, D; Paul, E; Robin, P; Paillat, J M

    2012-01-01

    Composting is a complex bioprocess, requiring a lot of empirical experiments to optimize the process. A dynamical mathematical model for the biodegradation of the organic matter during the composting process has been developed. The initial organic matter expressed by chemical oxygen demand (COD) is decomposed into rapidly and slowly degraded compartments and an inert one. The biodegradable COD is hydrolysed and consumed by microorganisms and produces metabolic water and carbon dioxide. This model links a biochemical characterization of the organic matter by Van Soest fractionating with COD. The comparison of experimental and simulation results for carbon dioxide emission, dry matter and carbon content balance showed good correlation. The initial sizes of the biodegradable COD compartments are explained by the soluble, hemicellulose-like and lignin fraction. Their sizes influence the amplitude of the carbon dioxide emission peak. The initial biomass is a sensitive variable too, influencing the time at which the emission peak occurs.

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

    Science.gov (United States)

    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.

  6. Organic Matter in Space (IAU S251)

    Science.gov (United States)

    Kwok, Sun; Sanford, Scott

    2009-01-01

    Preface; From the local organising committee; Organising committee; Conference participants; Opening address of Symposium 251 C. Cesarsky; Session I. Observations of organic compounds beyond the Solar System William Irvine, Ewine van Dishoeck, Yvonne Pendleton and Hans Olofsson; Session II. Organic compounds within the Solar System Scott Sandford, Ernst Zinner and Dale Cruikshank; Session III. Laboratory analogues of organic compounds in space Max Bernstein and Thomas Henning; Banquet speech; Author index; Object index.

  7. Microbial bioavailability regulates organic matter preservation in marine sediments

    NARCIS (Netherlands)

    Koho, K.A.; Nierop, K.G.J.; Moodley, L.; Middelburg, J.J.; Pozzato, L.; Soetaert, K.; van der Plicht, J.; Reichart, G.J.

    2013-01-01

    Burial of organic matter (OM) plays an important role in marine sediments, linking the short-term, biological carbon cycle with the long-term, geological subsurface cycle. It is well established that low-oxygen conditions promote organic carbon burial in marine sediments. However, the mechanism

  8. Organic Matter Application Can Reduce Copper Toxicity in Tomato Plants

    Science.gov (United States)

    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,…

  9. Organic Matter Application Can Reduce Copper Toxicity in Tomato Plants

    Science.gov (United States)

    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,…

  10. Organic Matter of the Mulhouse Basin, France: A synthesis

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Hofmann, P.; Huc, A.Y.; Carpentier, B.; Schaeffer, P.; Albrecht, P.; Keely, B.J.; Maxwell, J.R.; Leeuw, J.W. de; Leythaeuser, D.

    1993-01-01

    The lower Oligocene evaporite sequence of the Mulhouse Basin (France) contains organic matter-rich marl deposits. These marls display an overall cyclic variation of sedimentation rate, organic carbon content, hydrogen index and selected molecular parameters over a 30 m thick stratigraphic interval.

  11. Bacterial utilization of size-fractionated dissolved organic matter

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Bhosle, N.B.

    Dissolved organic matter (DOM) is an important source of organic carbon for sustaining the growth of heterotrophic bacteria. The bacterial utilization of high-molecular-weight (HMW; greater than 30 kDa to 0.22 mu m) and low-molecular-weight (LMW...

  12. Organic matter degradation in Lake Baikal - a sediment trap study

    DEFF Research Database (Denmark)

    Schubert, Carsten J.; Niggemann, Jutta; Lomstein, Bente Aagaard

    Lake Baikal offers a unique opportunity to study water column processes in a freshwater system with conditions similar to oceanic systems, e. g. great water depth and oxygenated water column. Investigations on sediment trap material provide information on the early stages of organic matter...... and composition of amino acids and fatty acids. The extent of organic matter degradation in the water column of Lake Baikal is reflected in the fluxes of total organic carbon, chlorins, amino acids, and fatty acids at different water depths. In line with earlier studies in marine systems, the labile compounds......, and the Fatty Acid Index [2]. All indicators showed consistent trends, indicating that the diagenetic stage of the sediment trap material increased with increasing water depth. This study of sediment trap material from Lake Baikal provided interesting insights in organic matter degradation in this unique...

  13. Effects of Organic Matter on the Growth of Thiobacillus intermedius

    Science.gov (United States)

    London, Jack; Rittenberg, Sydney C.

    1966-01-01

    London, Jack (University of California, Los Angeles), and Sydney C. Rittenberg. Effects of organic matter on the growth of Thiobacillus intermedius. J. Bacteriol. 91:1062–1069. 1966.—Yeast extract, glucose, glutamate, and other organic materials stimulate the rate and extent of growth of Thiobacillus intermedius in thiosulfate broth. Growth did not occur in glucose or glutamate mineral salts medium in the absence of thiosulfate, although a stable variant was obtained which grows on yeast extract alone. Cells harvested from media supplemented with organic matter have a reduced rate of thiosulfate oxidation (20 to 30% of autotrophic), oxidize the organic supplement, and have an additive rate of oxidation in the presence of both the organic substrate and thiosulfate. Carboxydismutase synthesis is repressed, and the incorporation of bicarbonate carbon into cell material is almost completely eliminated by the presence of organic matter in the growth medium. It is concluded that the availability of organic matter eliminates the autotrophic assimilatory mechanisms of T. intermedius but not its autotrophic energy-generating system. The data are discussed in relation to the existence of “obligate” chemoautotrophic bacteria. PMID:5929743

  14. Organic matter in comets and cometary dust.

    Science.gov (United States)

    Llorca, Jordi

    2005-03-01

    Comets are primitive conglomerates of the solar system containing a mixture of frozen gases, refractory grains, and carbonaceous particles rich in biogenic elements. The dramatic display of comets is mostly caused by a cloud of micrometer-sized dust particles that leave the comet nucleus when frozen gases sublimate as they approach the Sun. Analyses of cometary dust captured in the stratosphere together with data obtained from space missions to comets have revealed the presence of a great variety of organic molecules. Since substantial amounts of cometary dust were gently deposited on Earth, their organic content could have played a major role in prebiotic processes prior to the appearance of microorganisms. This review discusses the description and implications for life of the organic content of comets and cometary dust.

  15. Transplanting an organization: how does culture matter.

    Science.gov (United States)

    Munich, Richard L

    2011-01-01

    Cultural differences are often cited as a major obstacle to the successful transition/integration into new situations of organizations. In this contribution, the author details the changing cultural factors impacting the operation and move of the Menninger Clinic from autonomous status to an affiliation with and first year of operation in the Baylor College of Medicine and Methodist Hospital Health Care System. Both functional and dysfunctional consequences are outlined, and specific examples illustrate how the organization's leadership and staff struggled to adapt during this complicated process. Based on the experience within the Clinic, general recommendations for managing such an acculturation are provided.

  16. Organic Matter in Space - an Overview

    CERN Document Server

    Van Dishoeck, E F

    2008-01-01

    Organic compounds are ubiquitous in space: they are found in diffuse clouds, in the envelopes of evolved stars, in dense star-forming regions, in protoplanetary disks, in comets, on the surfaces of minor planets, and in meteorites and interplanetary dust particles. This brief overview summarizes the observational evidence for the types of organics found in these regions, with emphasis on recent developments. The Stardust sample-return mission provides the first opportunity to study primitive cometary material with sophisticated equipment on Earth. Similarities and differences between the types of compounds in different regions are discussed in the context of the processes that can modify them. The importance of laboratory astrophysics is emphasized.

  17. Bacterial Selection from Shrimp Ponds for Degradation of Organic Matters

    OpenAIRE

    Powtongsook, S.; Chanpun, K.; Suntornsuk, W.

    2007-01-01

    Accumulation of ammonia, nitrite and hydrogen sulfide in a shrimp pond is generally caused by incomplete degradation of residual organic matters from overfeeding and from organic wastes released by shrimps. The phenomenon affects shrimp growth and survival rate. The objectives of this investigation were to screen for a bacterial strain able to digest organic residues and to evaluate the changes of residues by bacterial activities under natural conditions. The results from this work showed tha...

  18. Inputs of organic matter to the ocean

    NARCIS (Netherlands)

    Duce, R.A.; Duursma, E.K.

    1977-01-01

    The first objective of this introductory paper is to summarize our present understanding of the quantities of total organic carbon produced in the ocean by photosynthesis and non-biotic photochemical reactions, and the amount entering the ocean from rivers, the atmosphere, and the sediments. In this

  19. Organic matter decomposition in simulated aquaculture ponds

    NARCIS (Netherlands)

    Torres Beristain, B.

    2005-01-01

    Different kinds of organic and inorganic compounds (e.g. formulated food, manures, fertilizers) are added to aquaculture ponds to increase fish production. However, a large part of these inputs are not utilized by the fish and are decomposed inside the pond. The microbiological decomposition of the

  20. Effect of Fertilizer and Incorporated Organic Matter

    African Journals Online (AJOL)

    organic residues and fertilizer application on gaseous N20 fluxes was studied in a field trial at .... Natural fallow served as the control. .... calculated as (total fluxes from the 15 kg urea ha "'-treatment) - (total fluxes from the 0 .... SAS Release 8.1.

  1. Degradation Mechanisms of Colloidal Organic Matter in Biofilm Reactors

    DEFF Research Database (Denmark)

    Larsen, Tove; Harremoës, Poul

    1994-01-01

    The degradation mechanisms of colloidal organic matter in biofilm reactors have been studied in an idealized laboratory reactor system with soluble starch as a model substrate. Batch tests and experiments with different reactor configurations have shown that for this specific substrate, bulk liquid......-diffusible organic matter in a biofilm reactor. DH depends on the combined volumetric and surface hydraulic loading rate, Q2/(AV). In full-scale wastewater treatment plants, the degradation mechanism presented in this paper can explain important differences between the performance of trickling filters and RBC...... hydrolysis is the mechanism for transforming non-diffusible organic matter into biofilm diffusible substrate. A simplified mathematical description has led to the identification of the degree of hydrolysis, DH, as the parameter expressing the major difference between degradation of diffusible and non...

  2. Scavenging of soluble organic matter from the prebiotic oceans.

    Science.gov (United States)

    Nissenbaum, A

    1976-12-01

    The existence of hot or cold "nutrient broth" or "primeval soup" is challenged on the basis of the recent geochemistry of soluble organic carbon in the oceans. Most of the dissolved organic carbon is recycled quickly by organisms, but the residual, biologically refractive, organic matter is efficiently scavenged from the oceans (residence time of 1000 to 3500 years) by nonbiologically mediated chemical and physical processes, such as adsorption on sinking minerals, polymerization and aggregation to humic type polymers or by aggregation to particulate matter through bubbling and sinking of this material to the ocean bottom. Since there is no reason to believe that such nonbiological scavenging was not operative in the prebiotic oceans as well, then the prolonged existence of "organic soup" is very doubtful. The question of the origin of life is thus assumed to be related to solid-liquid interfacial activity, and the answer may be associated with sediment-water interaction rather than with solution chemistry.

  3. Influence of organic matter on collembolan communities in reedbed habitats

    Science.gov (United States)

    Uteseny, K.; Drapela, T.; Frouz, J.

    2009-04-01

    The combination of the organic matter, micro-climatic environments and plant cover belongs to important factors for the distribution of soil meso-fauna, especially Collembola. There are no studies attending to these factors on collembolan communities in reedbed vegetation. The main goals of our investigation were therefore to compare diversity of Collembola in redbed habitats of Lake Neudsiedl, eastern Austria, and to assess particularly the role of organic matter with regard to the collembolan community structure. Soil samples were taken from April 1997 to October 1997 at fifteen study sites covered with Phragmatis australis of different age. Changes in the structure and composition of the assemblages of Collembola were examined.

  4. Do soils loose phosphorus with dissolved organic matter?

    Science.gov (United States)

    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.

  5. Detection of organic matter in interstellar grains.

    Science.gov (United States)

    Pendleton, Y J

    1997-06-01

    Star formation and the subsequent evolution of planetary systems occurs in dense molecular clouds, which are comprised, in part, of interstellar dust grains gathered from the diffuse interstellar medium (DISM). Radio observations of the interstellar medium reveal the presence of organic molecules in the gas phase and infrared observational studies provide details concerning the solid-state features in dust grains. In particular, a series of absorption bands have been observed near 3.4 microns (approximately 2940 cm-1) towards bright infrared objects which are seen through large column densities of interstellar dust. Comparisons of organic residues, produced under a variety of laboratory conditions, to the diffuse interstellar medium observations have shown that aliphatic hydrocarbon grains are responsible for the spectral absorption features observed near 3.4 microns (approximately 2940 cm-1). These hydrocarbons appear to carry the -CH2- and -CH3 functional groups in the abundance ratio CH2/CH3 approximately 2.5, and the amount of carbon tied up in this component is greater than 4% of the cosmic carbon available. On a galactic scale, the strength of the 3.4 microns band does not scale linearly with visual extinction, but instead increases more rapidly for objects near the Galactic Center. A similar trend is noted in the strength of the Si-O absorption band near 9.7 microns. The similar behavior of the C-H and Si-O stretching bands suggests that these two components may be coupled, perhaps in the form of grains with silicate cores and refractory organic mantles. The ubiquity of the hydrocarbon features seen in the near infrared near 3.4 microns throughout out Galaxy and in other galaxies demonstrates the widespread availability of such material for incorporation into the many newly forming planetary systems. The similarity of the 3.4 microns features in any organic material with aliphatic hydrocarbons underscores the need for complete astronomical observational

  6. Andic soils : mineralogical effect onto organic matter dynamics, organic matter effect onto mineral dynamics, or both?

    Science.gov (United States)

    Basile-Doelsch, Isabelle; Amundson, Ronald; Balesdent, Jérome; Borschneck, Daniel; Bottero, Jean-Yves; Colin, Fabrice; de Junet, Alexis; Doelsch, Emmanuel; Legros, Samuel; Levard, Clément; Masion, Armand; Meunier, Jean-Dominique; Rose, Jérôme

    2014-05-01

    From a strictly mineralogical point of view, weathering of volcanic glass produces secondary phases that are short range ordered alumino-silicates (SRO-AlSi). These are imogolite tubes (2 to 3 nm of diameter) and allophane supposedly spheres (3.5 to 5 nm). Their local structure is composed of a curved gibbsite Al layer and Si tetrahedra in the vacancies (Q0). Proto-imogolites have the same local structure but are roof-shape nanoparticles likely representing the precursors of imogolite and allophanes (Levard et al. 2010). These structures and sizes give to the SRO-AlSi large specific surfaces and high reactivities. In some natural sites, imogolites and allophanes are formed in large quantities. Aging of these phases may lead to the formation of more stable minerals (halloysite, kaolinite and gibbsite) (Torn et al 1997). In natural environments, when the weathering of volcanic glass is associated with the establishment of vegetation, the soils formed are generally andosols. These soils are particularly rich in organic matter (OM), which is explained by the high ability of SRO-AlSi mineral phases to form bonds with organic compounds. In a first order "bulk" approach, it is considered that these bonds strongly stabilize the organic compounds as their mean age can reach more than 10 kyrs in some studied sites (Basile-Doelsch et al. 2005; Torn et al. 1997). However, the structure of the mineral phases present in andosols deserves more attention. Traditionally, the presence in the SRO-AlSi andosols was shown by selective dissolution approaches by oxalate and pyrophosphate. Using spectroscopic methods, mineralogical analysis of SRO-AlSi in andosols samples showed that these mineral phases were neither imogolites nor allophanes as originally supposed, but only less organized structures remained in a state of proto-imogolites (Basile-Doelsch al. 2005 ; Levard et al., 2012). The presence of OM would have an inhibitory effect on the formation of secondary mineral phases, by

  7. Composition of dissolved organic matter in groundwater

    Science.gov (United States)

    Longnecker, Krista; Kujawinski, Elizabeth B.

    2011-05-01

    Groundwater constitutes a globally important source of freshwater for drinking water and other agricultural and industrial purposes, and is a prominent source of freshwater flowing into the coastal ocean. Therefore, understanding the chemical components of groundwater is relevant to both coastal and inland communities. We used electrospray ionization coupled with Fourier-transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to examine dissolved organic compounds in groundwater prior to and after passage through a sediment-filled column containing microorganisms. The data revealed that an unexpectedly high proportion of organic compounds contained nitrogen and sulfur, possibly due to transport of surface waters from septic systems and rain events. We matched 292 chemical features, based on measured mass:charge ( m/z) values, to compounds stored in the Kyoto Encyclopedia of Genes and Genomes (KEGG). A subset of these compounds (88) had only one structural isomer in KEGG, thus supporting tentative identification. Most identified elemental formulas were linked with metabolic pathways that produce polyketides or with secondary metabolites produced by plants. The presence of polyketides in groundwater is notable because of their anti-bacterial and anti-cancer properties. However, their relative abundance must be quantified with appropriate analyses to assess any implications for public health.

  8. Adsorption combined with ultrafiltration to remove organic matter from seawater.

    Science.gov (United States)

    Tansakul, Chatkaew; Laborie, Stéphanie; Cabassud, Corinne

    2011-12-01

    Organic fouling and biofouling are the major severe types of fouling of reverse osmosis (RO) membranes in seawater (SW) desalination. Low pressure membrane filtration such as ultrafiltration (UF) has been developed as a pre-treatment before reverse osmosis. However, UF alone may not be an effective enough pre-treatment because of the existence of low-molecular weight dissolved organic matter in seawater. Therefore, the objective of the present work is to study a hybrid process, powdered activated carbon (PAC) adsorption/UF, with real seawater and to evaluate its performance in terms of organic matter removal and membrane fouling. The effect of different PAC types and concentrations is evaluated. Stream-activated wood-based PAC addition increased marine organic matter removal by up to 70% in some conditions. Moreover, coupling PAC adsorption with UF decreased UF membrane fouling and the fouling occurring during short-term UF was totally reversible. It can be concluded that the hybrid PAC adsorption/UF process performed in crossflow filtration mode is a relevant pre-treatment process before RO desalination, allowing organic matter removal of 75% and showing no flux decline for short-term experiments.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  11. Aggregation of organic matter by pelagic tunicates

    Energy Technology Data Exchange (ETDEWEB)

    Pomeroy, L.R. (Univ. of Georgia, Athens); Deibel, D.

    1980-07-01

    Three genera of pelagic tunicates were fed concentrates of natural seston and an axenic diatom culture. Fresh and up to 4-day-old feces resemble flocculent organic aggregates containing populations of microorganisms, as described from highly productive parts of the ocean, and older feces resemble the nearly sterile flocculent aggregates which are ubiquitous in surface waters. Fresh feces consist of partially digested phytoplankton and other inclusions in an amorphous gelatinous matrix. After 18 to 36 h, a population of large bacteria develops in the matrix and in some of the remains of phytoplankton contained in the feces. From 48 to 96 h, protozoan populations arise which consume the bacteria and sometimes the remains of the phytoplankton in the feces. Thereafter only a sparse population of microorganisms remains, and the particles begin to fragment. Water samples taken in or below dense populations of salps and doliolids contained greater numbers of flocculent aggregates than did samples from adjacent stations.

  12. Ultrathin organic semiconductor films--soft matter effect.

    Science.gov (United States)

    Wang, Tong; Yan, Donghang

    2014-05-01

    The growth of organic semiconductor thin films has been a crucial issue in organic electronics, especially the growth at the early stages. The thin-film phase has been found to be a common phenomenon in many organic semiconductor thin films, which is closely related with the weak van der Waals interaction between organic molecules, the long-range interaction between organic molecules and the substrate, as well as the soft matter characteristics of ultrathin films. The growth behavior and soft matter characteristics of the thin-film phase have great effects on thin film morphology and structure, for example, the formation and coalescence of grain boundaries, which further influences the performance of organic electronic devices. The understanding of thin-film phase and its intrinsic quality is necessary for fabricating large-size, highly ordered, continuous and defect-free ultrathin films. This review will focus on the growth behavior of organic ultrathin films, i.e., the level of the first several molecular layers, and provide an overview of the soft matter characteristics.

  13. Can particulate organic matter reveal emerging changes in soil organic carbon?

    DEFF Research Database (Denmark)

    Simonsson, Magnus; Kirchmann, Holger; Magid, Jakob

    2014-01-01

    . Although organic matter in Fraction B had a higher intrinsic sensitivity to soil management, which was partly able to overcome the larger errors, we concluded that an observer would be more likely to detect changes by measuring total organic C and N, when monitoring decadal changes in C and N pools......This study assessed whether particulate organic matter (POM) in sand fractions, isolated by wet sieving after treatment with Na hexametaphosphate, can be a sensitive indicator of incipient changes in the content and composition of soil organic matter. In five long-term field experiments including....... This makes the investigated POM fractions less suitable as indicators for changes in soil C stocks. However, the C/N ratio of Fraction B showed a distinct signature of the history of organic matter input to the soil, which was absent in the C/N ratio of the total fine earth....

  14. Biodegradable organic matter in municipal solid waste incineration bottom ash.

    Science.gov (United States)

    Zhang, Shuo; Herbell, Jan-Dirk; Gaye-Haake, Birgit

    2004-01-01

    For investigation of the behavior of municipal solid waste incineration bottom ash in landfill, we have analysed bottom ash samples taken after the quench tank as well as after five months of storage in the laboratory for elements and organic constituents. Water extractable organic carbon, particulate organic carbon, amino acids, hexosamines and carbohydrates considerably decreased during the five months of storage and their spectra revealed microbial reworking. This shows that the organic matter present in the bottom ash after incineration can provide a substrate for microbial activity. The resulting changes of the physico-chemical environment may effect the short-term behavior of the bottom ash in landfill. Copyright 2004 Elsevier Ltd.

  15. Lyophilization and Reconstitution of Reverse Osmosis Concentrated Natural Organic Matter

    Science.gov (United States)

    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...

  16. The energetic and chemical signatures of persistent soil organic matter

    DEFF Research Database (Denmark)

    Barré, Pierre; Plante, Alain F.; Cecillon, Lauric

    2016-01-01

    A large fraction of soil organic matter (OM) resists decomposition over decades to centuries as indicated by long radiocarbon residence times, but the mechanisms responsible for the long-term (multi-decadal) persistence are debated. The current lack of mechanistic understanding limits our ability...

  17. Selective depletion of organic matter in mottled podzol horizons

    NARCIS (Netherlands)

    Buurman, P.; Schellekens, J.; Fritze, H.; Nierop, K.G.J.

    2007-01-01

    Abstract: Some well-drained podzols on quartz sands in the Netherlands and neighbouring Belgium and Germany show mottling in all horizons due to selective removal of organic matter. Phospholipid analysis and morphology of the mottles suggests that this removal is due to activity of fungi. Investigat

  18. Lyophilization and Reconstitution of Reverse Osmosis Concentrated Natural Organic Matter

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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 ...

  20. Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

    NARCIS (Netherlands)

    Kim, J.-H.; Peterse, F.; Willmott, V.; Klitgaard Kristensen, D.; Baas, M.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Soils, fine-grained ice-rafted detritus (IRD), coals, and marine surface sediments in the Arctic realm (Svalbard) were collected in 2007 and 2008 to characterize organic matter (OM) sources in Arctic marine sediments. Bulk geochemical (C : N ratio and stable carbon isotopic composition) parameters s

  1. Large ancient organic matter contributions to Arctic marine sediments (Svalbard)

    NARCIS (Netherlands)

    Kim, J.-H.; Peterse, F.; Willmott, V.; Klitgaard Kristensen, D.; Baas, M.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Soils, fine-grained ice-rafted detritus (IRD), coals, and marine surface sediments in the Arctic realm (Svalbard)were collected in 2007 and 2008 to characterize organic matter (OM) sources in Arctic marine sediments. Bulkgeochemical (C : N ratio and stable carbon isotopic composition) parameters sug

  2. SOMPROF: A vertically explicit soil organic matter model

    NARCIS (Netherlands)

    Braakhekke, M.C.; Beer, M.; Hoosbeek, M.R.; Kruijt, B.; Kabat, P.

    2011-01-01

    Most current soil organic matter (SOM) models represent the soil as a bulk without specification of the vertical distribution of SOM in the soil profile. However, the vertical SOM profile may be of great importance for soil carbon cycling, both on short (hours to years) time scale, due to

  3. Reactivity of Organic Matter and other Reductants in Aquifer Sediments

    NARCIS (Netherlands)

    Hartog, N.

    2003-01-01

    The molecular composition and the carbon isotope signature of sedimentary organic matter (SOM) and indicate that SOM is predominantly derived from higher land plants in sediments of both terrestrial as marine origins. The reactivity of SOM in the aquifer sediments studied is determined by the extent

  4. Organic matter dynamics in coarse sandy calcareous soils

    NARCIS (Netherlands)

    Pronk, A.A.; Reuler, van H.

    2011-01-01

    The decomposition of organic matter in coarse sandy calcareous soils (beach sand) is thought to be much higher than in acid fine sandy soils but relatively little research is performed on these soils. Laboratory incubation experiments in which the release of soil carbon (C) is determined may overest

  5. Inner filter correction of dissolved organic matter fluorescence

    DEFF Research Database (Denmark)

    Kothawala, D.N.,; Murphy, K.R.; Stedmon, Colin

    2013-01-01

    The fluorescence of dissolved organic matter (DOM) is suppressed by a phenomenon of self-quenching known as the inner filter effect (IFE). Despite widespread use of fluorescence to characterize DOM in surface waters, the advantages and constraints of IFE correction are poorly defined. We assessed...

  6. The Relationship Between Dissolved Organic Matter Composition and Organic Matter Optical Properties in Freshwaters

    Science.gov (United States)

    Aiken, G.; Spencer, R. G.; Butler, K.

    2010-12-01

    Dissolved organic matter (DOM) chemistry and flux are potentially useful, albeit, underutilized, indicators of watershed characteristics, climate influences on watershed hydrology and soils, and changes associated with resource management. Source materials, watershed geochemistry, oxidative processes and hydrology exert strong influences on the nature and reactivity of DOM in aquatic systems. The molecules that comprise DOM, in turn, control a number of environmental processes important for ecosystem function including light penetration and photochemistry, microbial activity, mineral dissolution/precipitation, and the transport and reactivity of hydrophobic compounds and metals (e.g. Hg). In particular, aromatic molecules derived from higher plants exert strong controls on aquatic photochemistry, and on the transport and biogeochemistry of metals. Assessment of DOM composition and transport, therefore, can provide a basis for understanding watershed processes and biogeochemistry of rivers and streams. Here we present results of multi-year studies designed to assess the seasonal and spatial variability of DOM quantity and quality for 57 North American Rivers. DOM concentrations and composition, based on DOM fractionation on XAD resins, ultraviolet (UV)/visible absorption and fluorescence spectroscopic analyses, and specific compound analyses, varied greatly both between sites and seasonally within a given site. DOM in these rivers exhibited a wide range of concentration (4000 µM C* L-1) and specific ultra-violet absorbance at 254 nm (SUVA254) (0.6 to 5 L *mg C-1 *m-1), an optical measurement that is an indicator of aromatic carbon content. In almost all systems, UV absorbance measured at specific wavelengths (e.g. 254 nm) correlated strongly with DOM and hydrophobic organic acid (HPOA) content (aquatic humic substances). The relationships between dissolved organic carbon (DOC) concentration and absorbance for the range of systems were quite variable due to

  7. Molecular and spectroscopic analysis of non-hydrolyzable sedimentary organic matter from the St. Lawrence Estuary

    Science.gov (United States)

    Ibrahim, M.; Simpson, A. J.; Gelinas, Y.

    2011-12-01

    Sediments are the ultimate long-term sink for organic carbon (OC) on Earth, thus playing an important role in the global cycles of O2 and CO2. Estuaries and river deltas are major conduits for terrestrial organic matter (OM) into marine systems, where it is mixed with locally produced OM and is eventually deposited and buried in the sediment bed. About 45% of global OC burial occurs along these river deltas and estuaries (Hedges and Keil, 1995), therefore it is of interest to follow OM deposition and preservation in these terrestrial to marine transition zones. We chemically fractionated bulk OM from a series of sediments from the St. Lawrence Estuary and Gulf into distinct reactivity classes. We define three such OM fractions based on pioneering work by Hedges and Keil (1995) who classified OM based on chemical reactivities: labile (degradable at similar rate under oxic and anoxic conditions), non-hydrolyzable (degraded primarily under oxic conditions), and refractory (preserved on long time scales independently of redox conditions). Here we present data on the elemental (C and N), isotopic (δ13C and δ15N) and spectroscopic (FTIR, HR-MAS 1H/13C NMR) characterization of the different fractions, focusing primarily on the non-hydrolyzable fraction because of its importance in the long-term burial of OC below the seafloor. We used mild oxidation methods (cupric oxide and ruthenium tetroxide oxidation) followed by chromatographic analysis of the oxidation products. Combining results from the bulk and molecular analytical techniques provides insights into the composition and cycling of non-hydrolyzable OM in transitional system, from which OM preservation can be better understood. Hedges, J. I., Keil, Richard G. (1995). "Sedimentary organic matter preservation: an assessment and speculative synthesis." Marine Chemistry 49(2-3): 81-115.

  8. Natural organic matter properties in Swedish agricultural streams

    Science.gov (United States)

    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.

  9. HUMIFIED FRACTION OF ORGANIC MATTER DUE TO PLANT MIXTURE CULTIVATION

    Directory of Open Access Journals (Sweden)

    TONY JARBAS FERREIRA CUNHA

    2016-01-01

    Full Text Available The aim of this study was to assess the organic matter changes in quantity and quality, particularly of the humic fraction in the surface layer (0–20 cm, of a Typic Plinthustalf soil under different management of plant mixtures used as green manure for mango (Mangifera indica L. crops. The plant mixtures, which were seeded between rows of mango trees, were formed by two groups of leguminous and non-leguminous plants. Prior to sowing, seeds were combined in different proportions and compositions constituting the following treatments: 100% non-leguminous species (NL; 100% leguminous species (L; 75% L and 25% NL; 50% L and 50% NL; 25% L and 75% NL; and 100% spontaneous vegetation, considered a control. The plant mixtures that grew between rows of mango trees caused changes in the chemical composition of the soil organic matter, especially for the treatments 50% L and 50% NL and 25% L and 75% NL, which increased the content of humic substances in the soil organic matter. However, the treatment 25% L and 75% NL was best at minimising loss of total organic carbon from the soil. The humic acids studied have mostly aliphatic characteristics, showing large amounts of carboxylic and nitrogen groups and indicating that most of the organic carbon was formed by humic substances, with fulvic acid dominating among the alkali soluble fractions.

  10. Cumulative effects of biochar, mineral and organic fertilizers on soil organic matter

    Science.gov (United States)

    Plaza, César; López-de-Sá, Esther G.; Gascó, Gabriel; Méndez, Ana; Zaccone, Claudio

    2016-04-01

    We investigated the effect of three consecutive annual applications of biochar at rates of 0 and 20 t ha-1, in a factorial combination with a mineral fertilizer (NPK and nitrosulfate) and two types of organic amendment (municipal solid waste compost and sewage sludge), on soil organic matter in a field experiment under Mediterranean conditions. Biochar increased significantly soil organic C content and C/N ratio. In biochar-amended soils, soil organic C increased significantly with the addition of municipal solid waste compost and sewage sludge. To capture organic matter protection mechanisms related to aggregation and mineral interaction, the soil samples will be fractionated into free (unprotected), intra-macroaggregate, intra-microaggregate, and mineral-associated organic matter pools, and the isolated fractions will be subjected to further chemical and spectroscopic analysis.

  11. Microbial bioavailability regulates organic matter preservation in marine sediments

    Directory of Open Access Journals (Sweden)

    K. A. Koho

    2012-09-01

    Full Text Available Burial of organic matter (OM plays an important role in marine sediments, linking the short-term, biological carbon cycle with the long-term, geological subsurface cycle. It is well established that low-oxygen conditions promote organic carbon burial in marine sediments. However, the mechanism remains enigmatic. Here we report biochemical quality, microbial degradability, OM preservation and accumulation along an oxygen gradient in the Indian Ocean. Our results show that more OM, and of biochemically higher quality, accumulates under low oxygen conditions. Nevertheless, microbial degradability does not correlate with the biochemical quality of OM. This decoupling of OM biochemical quality and microbial degradability, or bioavailability, violates the ruling paradigm that higher quality implies higher microbial processing. The inhibition of bacterial OM remineralisation may play an important role in the burial of organic matter in marine sediments and formation of oil source rocks.

  12. Aggregate Development and Organic Matter Storage in Mediterranean Mountain Soils

    Institute of Scientific and Technical Information of China (English)

    R.M.POCH; M.ANT(U)NEZ

    2010-01-01

    Soil aggregation and organic matter of soils from the pre-Pyrenean range in Catalonia (NE Spain) were studied, in order to assess their quality as carbon sinks and also to select the best soil management practices to preserve their quality.Aggregate stability, organic carbon and micromorphology were investigated. The highest amount of organic carbon was found in alluvial, deep soils (228 Mg C ha-1), and the lowest was in a shallow, stony soil with a low plant cover (78 Mg C ha-1). Subsurface horizons of degraded soils under pastures were the ones with smaller and less-stable aggregates.Fresh residues of organic matter (OM) were found mostly in interaggregate spaces. Within the aggregates there were some organic remains that were beginning to decompose, and also impregnative nodules of amorphous OM. Although OM was evenly distributed among the aggregate fractions, the larger blocky peels had more specific surface, contained less decomposed OM and had a lower organic/mineral interphase than smaller crumb aggregates, which were also more stable.Soil carbon storage was affected primarily by the OM inputs in the surface horizons. In order to store organic carbon over the mid- and long-term periods, the mechanisms favouring structuration through biological activity and creating small aggregates with intrapedal stable microporosities seemed to be the most effective.

  13. Effect of Cultivation on Soil Organic Matter and Aggregate Stability

    Institute of Scientific and Technical Information of China (English)

    A.WILLIAMS; XING Bao-Shan; P.VENEMAN

    2005-01-01

    Agricultural sustainability relates directly to maintaining or enhancing soil quality. Soil quality studies in Canada during the 1980's showed that loss of soil organic matter (SOM) and soil aggregate stability was standard features of non-sustainable land management in agroecosystems. In this study total soil organic carbon (SOC), particulate organic matter (POM), POM-C as a percentage of total SOC, and aggregate stability were determined for three cultivated fields and three adjacent grassland fields to assess the impact of conventional agricultural management on soil quality. POM was investigated using solid-state 13C nuclear magnetic resonance (NMR) to determine any qualitative differences that may be attributed to cultivation. Results show a highly significant loss in total SOC, POM and aggregate stability in the cultivated fields as compared to the grassland fields and a significant loss of POM-C as a percentage of total SOC.Integrated results of the NMR spectra of the POM show a loss in carbohydrate-C and an increase in aromatic-C in the cultivated fields, which translates to a loss of biological lability in the organic matter. Conventional cultivation decreased the quantity and quality of SOM and caused a loss in aggregate stability resulting in an overall decline in soil quality.

  14. Bacterial Selection from Shrimp Ponds for Degradation of Organic Matters

    Directory of Open Access Journals (Sweden)

    Powtongsook, S.

    2007-01-01

    Full Text Available Accumulation of ammonia, nitrite and hydrogen sulfide in a shrimp pond is generally caused by incomplete degradation of residual organic matters from overfeeding and from organic wastes released by shrimps. The phenomenon affects shrimp growth and survival rate. The objectives of this investigation were to screen for a bacterial strain able to digest organic residues and to evaluate the changes of residues by bacterial activities under natural conditions. The results from this work showed that the isolated strain, Bacillus cereus S1, had the highest protease activity (57.1 U/ml with the presence of glucoamylase and lipase activities (4.5 and 0.13 U/ml, respectively. Under an aseptic condition in 1-L flasks containing seawater with 0.1% shrimp feed, B. cereus S1 degraded organic matters and significantly reduced chemical oxygen demand (COD (70.8%. An amount of ammonia-nitrogen was increased during the first 5 days of incubation due to the degradation of organic compounds in shrimp feed. However, it declined afterward with nitrate-nitrogen increase and unchanged nitrite nitrogen content. Under natural conditions in 10-L glass jars containing seawater with 0.05% shrimp feed and 0.05% sediment, B. cereus S1 and a commercial bacterial product (Inpicin-G could reduce COD (4.5% and 15.8%, respectively and biochemical oxygen demand (BOD (35.1 and 11.4%, respectively. However, similar changes of ammonia-nitrogen, nitrate-nitrogen and nitrite-nitrogen contents in water samples were observed. The results indicate that this selected bacterium could reduce organic compound accumulations on a laboratory scale. In addition, the strain did not produce any enterotoxins compared to a toxin standard. Therefore, the bacterium, Bacillus cereus S1, could be applied to decrease organic matters accumulated in shrimp pond without any harm to shrimps or consumers.

  15. Size-fractionated production and bioavailability of dissolved organic matter

    DEFF Research Database (Denmark)

    Knudsen-Leerbeck, Helle; Bronk, Deborah A.; Markager, Stiig

    Production and bioavailability of dissolved organic matter was quantified on a time scale of two days from size fractions ranging from bacteria to zooplankton in the York River, Virginia. The goal was to find the main contributor to DOM. Batch incubation experiments were labeled with N15-ammonium...... was mainly in the phytoplankton size fraction, which on average contributed 62 % of total particulate nitrogen and 61 % of total particulate carbon. Up to 5 ± 0.4 μmol dissolved organic nitrogen L-1 and 33 ± 6.2 μmol dissolved organic carbon L-1 was produced during the incubation. Bioavailability...... of phytoplankton produced dissolved organic carbon was 12 ± 1 % and higher than in the presence of bacteria, microzooplankton, or copepods (7 ± 3 %). The pattern for bioavailability of dissolved organic nitrogen was less clear and ranged from 4 – 7 %. This study revealed that phytoplankton was the main contributor...

  16. Effect of Various Organic Matter stimulates Bacteria and Arbuscular Mycorrhizal Fungi Plantations on Eroded Slopes in Nepal

    Science.gov (United States)

    Shrestha Vaidya, G.; Shrestha, K.; Wallander, H.

    2009-04-01

    Erosion resulting from landslides is a serious problem in mountainous countries such as Nepal. To restore such sites it is essential to establish plant cover that protects the soil and reduces erosion. Trees and shrubs on the lower hillsides in Nepal form symbiosis with arbuscular mycorrhizal (AM) fungi and these fungi are important for the uptake of mineral nutrients from the soil. In addition, the mycelia formed by these fungi have an important function in stabilizing the soil. The success of plantations of these eroded slopes is therefore highly dependent on the extent of mycorrhizal colonization of the plants. Mycorrhizal fungi growing in symbiosis with plants are essential in this respect because they improve both plant and nutrient uptake and soil structure. We investigated the influence of organic matter and P amendment on recently produced biomass of bacteria and arbuscular mycorrhizal (AM) fungi in eroded slopes in Nepal. Eroded soil mixed with different types of organic matter was placed in mesh bags which were buried around the trees of Bauhinia purpurea and Leucaena diversifolia .This experiment were done in two seasons ( (the wet and the dry season). Signature fatty acids were used to determine bacterial and AM fungal biomass after the six month intervals. The amount and composition of AM fungal spores were analyzed in the mesh bags from the wet and dry seasons. More microbial biomass was produced during wet season than during dry season. Further more, organic matter addition enhanced the production of AM fungal and bacterial biomass during both seasons. The positive influence of organic matter addition on AM fungi could be an important contribution to plant survival, growth and nutrient composition in the soil in plantations on eroded slopes. Different AM spore communities and bacterial profiles were obtained with different organic amendments and this suggests a possible way of selecting for specific microbial communities in the management of eroded

  17. [Characteristics and environmental significance of soil dissolved organic matter].

    Science.gov (United States)

    Zhao, Jinsong; Zhang, Xudong; Yuan, Xing; Wang, Jing

    2003-01-01

    Soil is a complex ecosystem with multi-interface. A numerous studies on soil dissolved organic matter (DOM) were carried out, and proved that DOM was one of the most active chemical components in the environment. Increasing attention has been paid on the study of soil DOM, especially in recent years, and the study has become an interdisciplinary focus in the fields of soil science, ecology, and environmental science due to the important roles of DOM in the biogeochemical cycles of carbon, nitrogen, phosphorus, sulfur, etc. In addition, DOM has significant effects on pedogenesis, growth and metabolism of soil microorganisms, decomposition and transformation of soil organic matter, and transport of pollutants in soils. The recent literatures about extraction methods, origin, composition, contents and controlling factors, bioavailability, and environmental significance of DOM were therefore reviewed, and future research aspects on this topic were also proposed.

  18. Cool oxygen plasma oxidation of the organic matter of coal

    Energy Technology Data Exchange (ETDEWEB)

    Korobetskii, I.A.; Nazimov, S.A.; Romanchuk, V.V. [COAL-C Ltd., Kemerovo (Russian Federation)

    1997-12-31

    Oxidation of the sapropelitic coals has been carried out by cool oxygen plasma. The changes in concentration of oxygen- and hydrogen-containing groups of organic matter were observed by photoacoustic FTIR-spectroscopy during the cool oxygen plasma oxidation (COPO). The accumulation of oxygen-containing bands, such as C-O and O-H, during COPO was shown. The complete elimination of aromatic and aliphatic structure occurred in first two hours of oxidation. (orig.)

  19. The Biogeochemistry of Chromophoric Dissolved Organic Matter in Coastal Waters

    Science.gov (United States)

    2016-06-07

    The Biogeochemistry of Chromophoric Dissolved Organic Matter in Coastal Waters Robert F. Chen Environmental , Coastal and Ocean Sciences University of...properties to governing physical processes in high energy environments such as coastal seas. In addition, large spatial coverage over a wide range of...optical measurements of CDOM. In order to reliably predict the important photochemical, biological, and chemical processes governing CDOM, and hence its

  20. Thermodynamics of uranium/organic matter interactions in hydrothermal systems

    Science.gov (United States)

    Richard, L.

    2003-04-01

    Organic matter is commonly encountered in and around uranium and other ore deposits, which raises the question of the role played by organic compounds in the formation of these deposits (Landais and Gize, 1997). One of the best known examples is the observation of uraninite crystals entrapped within solid bitumens in the Oklo natural reactors. This observation led Nagy et al. (1991) to propose that a liquid, aliphatic-rich bitumen may have acted as a reductant to precipitate uraninite from hydrothermal solutions according to the reaction VIUO2+2(aq)+H_2O(l)=IVUO2(c)+2H^+(aq)+0.5 O2(g). The liquid bitumen was simultaneously oxidized into a polyaromatic solid, which may be represented by the reaction 2.7n- C20H42(l) + 17.85 O2(g) = C54H42(c)+35.7 H_2O(l) where n-C20H42(l) denotes n-eicosane present in the liquid bitumen, and C54H42(c) represents an idealized polyaromatic solid. Recent advances in theoretical organic geochemistry made it possible to generate a comprehensive thermodynamic database for hundreds of crystalline, liquid, gas and aqueous organic compounds of geochemical interest (Shock and Helgeson, 1990; Shock, 1995; Amend and Helgeson, 1997; Helgeson et al., 1998; Richard and Helgeson, 1998; Richard, 2001), which can be used together with thermodynamic properties for uranium-bearing minerals and aqueous species (Grenthe et al., 1992; Shock et al., 1997) to characterize uranium/organic matter interactions in hydrothermal systems as a function of temperature, pressure, oxygen fugacity, and organic matter composition. Activity-fO_2 diagrams have been constructed at a series of temperatures and pressures to investigate possible genetic relationships between uranium mineralizations and solid bitumens of various compositions.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Kirwan, M. L.; Guntenspergen, G. R.; Langley, J. A.

    2014-09-01

    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.

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

    Science.gov (United States)

    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.

  4. Plutonium Immobilization and Mobilization by Soil Organic Matter

    Energy Technology Data Exchange (ETDEWEB)

    Santschi, Peter H. [Texas A& M University, Galveston, TX (United States); Schwehr, Kathleen A. [Texas A& M University, Galveston, TX (United States); Xu, Chen [Texas A& M University, Galveston, TX (United States); Athon, Matthew [Texas A& M University, Galveston, TX (United States); Ho, Yi-Fang [Texas A& M University, Galveston, TX (United States); Hatcher, Patrick G. [Old Dominion Univ., Norfolk, VA (United States); Didonato, Nicole [Old Dominion Univ., Norfolk, VA (United States); Kaplan, Daniel I. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-08

    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 NOM 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 organic

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

    Science.gov (United States)

    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  0.95, p oceans.

  6. Photocatalytic Removal of Microbiological Consortium and Organic Matter in Greywater

    Directory of Open Access Journals (Sweden)

    Nazmiye Cemre Birben

    2016-06-01

    Full Text Available This study aimed to investigate TiO2 photocatalytic degradation of synthetically-prepared greywater samples with differing compositional contents of organic matter (OM, anion concentration, and microbiological consortium. Treatment efficiency was followed through removal of organic matter content in terms of dissolved organic carbon (DOC, specific spectroscopic parameters, and bacterial inactivation. Photocatalytic degradation kinetics were expressed by pseudo first-order kinetic modeling. The best DOC removal rates were attained for greywater samples containing OM with lower molecular size fractions. In addition, either enhancing or reducing the effect of common anions as radical scavengers were observed depending on the composition and concentration of variables in the greywater matrix. Moreover, possibility of a photocatalytic disinfection process was found to be of a bacteria type specific in OM-loaded synthetic greywater samples. Photocatalytic destruction of fecal streptococci required longer irradiation periods under all conditions. Bacterial removal rates were found to be in the order of total coliform > fecal coliform > fecal streptococci, for low organic load greywater, and fecal coliform > total coliform > fecal streptococci, for high organic load greywater.

  7. Radiocarbon Dating of Soil Organic Matter Fractions in Andosols in Northern Ecuador

    NARCIS (Netherlands)

    Tonneijck, Femke H.; Plicht, Johannes van der; Jansen, Boris; Verstraten, Jacobus M.; Hooghiemstra, Henry

    2006-01-01

    Volcanic ash soils (Andosols) may offer great opportunities for paleoecological studies, as suggested by their characteristic accumulation of organic matter (OM). However, understanding of the chronostratigraphy of soil organic matter (SOM) is required. Therefore, radiocarbon dating of SOM is

  8. Characterization of fine organic particulate matter from Chinese cooking

    Institute of Scientific and Technical Information of China (English)

    HE Ling-yan; HU Min; WANG Li; HUANG Xiao-feng; ZHANG Yuan-hang

    2004-01-01

    PM2.5 samples were collected by a three-stage cascade impactor at two kinds of Chinese restaurants to characterize fine organic particulate matter from Chinese cooking sources. Major individual organic compounds have been quantified by GC/MS, including series of alkanes, n-alkanoic acids, n-alkanals, alkan-2-ones and PAHs.Alkanes and ketones make up a significant fraction of particle-phase organic compounds, ranging from C11 to C26,and C9 to C19, respectively. In addition, other organic compound classes have been identified, such as alkanols,esters, furans, lactones, amides, and nitriles. The mass concentrations of fine particles, alkanes, n-alkanoic acids and PAHs in air emitted from the Uigur style cooking are hundreds times higher than ambient PM2.5 in Beijing.

  9. Using Riverine Natural Organic Matter to Test the Hypothesis that Soil Organic Matter is Modified by Contact with Sodium Hydroxide

    Science.gov (United States)

    Perdue, E. Michael; Driver, Shamus; Hertkorn, Norbert; Harir, Mourad; Schmitt-Kopplin, Philippe

    2016-04-01

    It has been postulated by some scientists that soil humic acids and fulvic acids are an artifact of alkaline extractions of soil. Riverine natural organic matter (NOM) is obtained in part by dissolution and transport of organic matter from soils by meteoric waters at acidic to circumneutral pH. The NOM may be fractionated into humic acid (HA), fulvic acid (FA), and hydrophilic NOM by adsorption of HA and FA onto XAD-8 resin at pH < 2, followed by their desorption with NaOH at pH 13. Alternatively, riverine NOM may be concentrated using reverse osmosis (RO) and desalted by cation exchange. Several properties of Suwannee River NOM prior to its isolation, after concentration by RO, and after the XAD-8 process are compared to detect modifications that might have resulted from exposure of the sample to low and high pH.

  10. Soil organic matter regulates molybdenum storage and mobility in forests

    Science.gov (United States)

    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.

  11. The composition and degradability of upland dissolved organic matter

    Science.gov (United States)

    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.

  12. Organic matter and soil structure in the Everglades Agricultural Area

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Alan L. [Univ. of Florida, Gainesville, FL (United States); Hanlon, Edward A. [Univ. of Florida, Gainesville, FL (United States)

    2013-01-01

    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 effects 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 part or all

  13. Soil organic matter quality in intensive maize-based forage systems

    Science.gov (United States)

    Zavattaro, L.; Sacco, D.; Bertora, C.; Monaco, S.; Grignani, C.

    2009-04-01

    An experiment designed and managed as a long-term platform and aimed at studying the dynamics of soil organic matter (SOM) in 38 forage systems based on maize was started in 1992 on a deep calcareous loam soil. The treatments are typical of intensive livestock farms in the Po plain, NW Italy. The experimental design is a plot-scale, set up in 3 randomized blocks. Various techniques were combined to evaluate the N use efficiency and mineralization rates of different fresh organic material added to the soil: cattle slurry, farmyard manure (c. 230 and 350 kg ha-1 of N), maize stalks, roots or grass ley residues. The techniques concerning soil organic matter turnover included C and N annual budgets based on SOM content, in-situ incubations (net mineralization in buried bags), lab incubations (soil respiration, potentially mineralizable N PMN, soil microbial biomass SMB). The environmental impact of C and N cycle on groundwater and air quality was assessed through monitoring the soil and soil solution mineral N content, and the CO2, N2O and CH4 in-situ emissions using the closed chamber technique. While the crop yield and N uptake did not respond to types and levels of manures, the SOM amount and quality were modified by fertilization: treatments which received repeated applications of the different fresh organic materials increased SOM content and soil total N, but also the N supplying capacity, soil respiration and SMB when compared with soil that received no N fertilizer or urea. More in detail, farmyard manure additions in combination with the incorporation of maize stalks was the practice that mostly increased the total SOM content (C and N) and showed the maximum C sequestration potential (46% of C added as manure was retained in the soil), but fertilization with liquid slurry also exerted a potential in augmenting the soil C and N (26% of added C was retained), and the fraction of easily-mineralizable organic N. The residual effect of manures applied repeatedly

  14. Organic matter and seed survival of Striga hermonthica - Mechanisms for seed depletion in the soil

    NARCIS (Netherlands)

    Ayongwa, G.C.; Stomph, T.J.; Belder, P.; Leffelaar, P.A.; Kuyper, T.W.

    2011-01-01

    Seed survival of Striga hermonthica is influenced by amendments of organic matter; however, the role of organic matter quality (C:N ratio) and mechanisms for enhanced seed decay are inadequately understood. In a field experiment, plots received a single dose of 6 t organic matter per hectare but

  15. Organic chemistry of fluids from sediment-buried young basement: discrete sampling from ODP borehole 1301A & 1025C

    Science.gov (United States)

    Lin, H.; Cowen, J. P.; Amend, J. P.; Albert, D. B.; Glazer, B. T.; Rappe, M.; Jungbluth, S.; Matzinger, M.

    2010-12-01

    Hydrothermal systems profoundly influence seawater chemistry. However, the extent to which hydrothermal systems impact the quantity and the quality of the deep ocean dissolved organic carbon (DOC) pool remains unclear. To study the organic chemistry within sedimented ridge flank basement aquifers, discrete low temperature (~65°C & ~40°C) basement fluids were collected from Integrated Ocean Drilling Program boreholes via Circulation Obviation Retrofit Kit (CORK) observatories at 1301A (47°45N, 127°45W) and 1025C (47°53N, 128°39W) on the eastern flank of Juan de Fuca Ridge. The basement age is 1.24 Ma and 3.5 Ma at 1025C and 1301A, respectively. Basement fluids were collected using a new clean pumping system (Mobile Pump Valve Unit, or MPVU) and stored in acid-cleaned 60 L Large Volume Tedlar Bags (LVBS). A stainless steel fluid delivery line extends from the basement to the seafloor at 1301A; whereas fluids rise up the middle of the iron casing at 1025C. Here, concentration and preliminary characterization of the DOC will be presented, including labile organic components such as dissolved free and combined amino acids (DFAA & DCAA) and low molecular weight organic acids (LMW-OA). Our data show that compared to seawater levels, the DOC concentration in the younger basement fluid (1025C) was about one-half and in the older (1031A) was less than one-third. Relative to bottom seawater, the basement fluids are also depleted in SO42-, PO43-, NO3- and NO2-, but enriched in NH4+, H2S, Mn and Fe. Microbially mediated reduction of nitrate, sulfate, iron, and manganese and an array of heterotrophic metabolisms may explain these observations. Phylogenic trees based on 16S rRNA gene sequences from borehole 1301A fluids further support the presence of chemolithoautotrophic and heterotrophic organisms. Our preliminary results show that some dissolved free amino acids were slightly enriched in the 1301A basement fluid relative to bottom seawater. Thermodynamic calculations

  16. White matter microstructural organization and gait stability in older adults

    Directory of Open Access Journals (Sweden)

    Sjoerd M. Bruijn

    2014-06-01

    Full Text Available Understanding age-related decline in gait stability and the role of alterations in brain structure is crucial. Here, we studied the relationship between white matter microstructural organization using Diffusion Tensor Imaging (DTI and advanced gait stability measures in 15 healthy young adults (range 18-30 years and 25 healthy older adults (range 62-82 years.Among the different gait stability measures, only stride time and the maximum Lyapunov exponent (which quantifies how well participants are able to attenuate small perturbations were found to decline with age. White matter microstructural organization (FA was lower throughout the brain in older adults. We found a strong correlation between FA in the left anterior thalamic radiation and left corticospinal tract on the one hand, and step width and safety margin (indicative of how close participants are to falling over on the other. These findings suggest that white matter FA in tracts connecting subcortical and prefrontal areas is associated with the implementation of an effective stabilization strategy during gait.

  17. Chemical and isotopic composition of estuarine organic matter: implications for the relative contribution and reactivity of anthropogenic sources of organic matter

    Directory of Open Access Journals (Sweden)

    D. Shilla

    2014-10-01

    Full Text Available The source and composition of suspended particulate organic matter in the Manko estuary, Okinawa Island, Japan, has been evaluated using fatty acid biomarkers and stable carbon and nitrogen isotopes. Fatty acid signature and stable isotope data have revealed that terrestrial organic matter (including terrestrial vascular plants, bacteria, phytoplankton produced within the estuary and coastal sea, green macroalgae and mixed planktonic-sources predominantly contributed to the organic matter pool in the estuary. The combined approach has also allowed for the prediction of the following mixing regime and distribution of organic matter sources along the estuarine salinity gradient; Allochthonous, both terrestrial and river-borne organic matter which dominate the riverine section of the estuary seem to be slightly diluted with autochthonous organic matter in the middle estuary (site M and thereafter, in the lower reaches of the estuary (Site SW2 are measurably admixed with tidally introduced marine organic matter. However, the autochthonous primary production within the estuary seems to be highly dependent on the discharges of terrestrial organic matter and nutrients as depicted in fatty acid signatures and isotopic composition of residential and agricultural wastewater runoff. Isotopic composition of dissolved constituents (particularly, ammonia and nitrate highly influences the composition of autochthonous primary producers. The linkage between suspended organic matter sources and the diet of tilapia (Oreochromis mossambicus [Peters] is also discussed.

  18. Influence of land use on soil organic matter

    Science.gov (United States)

    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 (Change, pp 9-26 [2] Lal, R., et al., (2004), Soil carbon sequestration to mitigate climate change, Geoderma 123, 1-22. [3] IPCC, 2001. Summary for policymakers. In: Watson, R., (Ed.), Climate Change 2001: The Scientific Basis. Cambridge University Press, Cambridge, 1-20.

  19. Application of organic geochemistry to detect signatures of organic matter in the Haughton impact structure

    Science.gov (United States)

    Parnell, John; Lee, Pascal; Osinski, Gordon R.; Cockell, Charles S.

    2005-12-01

    Organic geochemistry applied to samples of bedrock and surface sediment from the Haughton impact structure detects a range of signatures representing the impact event and the transfer of organic matter from the crater bedrock to its erosion products. The bedrock dolomite contains hydrocarbon-bearing fluid inclusions which were incorporated before the impact event. Comparison of biomarker data from the hydrocarbons in samples inside and outside of the crater show the thermal signature of an impact. The occurrence of hydrocarbon inclusions in hydrothermal mineral samples shows that organic matter was mobilized and migrated in the immediate aftermath of the impact. The hydrocarbon signature was then transferred from bedrock to the crater-fill lacustrine deposits and present-day sediments in the crater, including wind-blown detritus in snow/ice. Separate signatures are detected from modern microbial life in crater rock and sediment samples. Signatures in Haughton crater samples are readily detectable because they include hydrocarbons generated by the burial of organic matter. This type of organic matter is not expected in crater samples on other planets, but the Haughton data show that, using very high resolution detection of organic compounds, any signature of primitive life in the crater rocks could be transferred to surface detritus and so extend the sampling medium.

  20. Source characterisation of Sedimentary organic matter in mangrove ecosystems of northern Kerala, India: Inferences from bulk characterisation and hydrocarbon biomarkers

    Digital Repository Service at National Institute of Oceanography (India)

    Resmi, P.; Manju, M.N.; Gireeshkumar, T.R.; RatheeshKumar, C.S.; Chandramohanakumar, N.

    diagenesis of sedimentary organic matter. The elemental and isotopic ratios along with sedimentary chlorophyll a content, suggested substantial contribution of planktonic organic matter apart from mangrove/terrestrial derived organic matter. The sources...

  1. Interactions Between Prokaryotes and Dissolved Organic Matter in Marine Waters

    DEFF Research Database (Denmark)

    Traving, Sachia Jo

    Microscopic unicellular organisms display a wealth of diversity, and occupy many different roles on Earth. Due to their ubiquitous distribution and high numbers, what they do and when they do it are of vital importance for the biogeochemical cycles on Earth. A large and important group of microbes...... are the heterotrophic bacteria and archaea, from here on collectively referred to as prokaryotes. They are specialized in consuming and re-mineralize organic material converting it into biomass and inorganic nutrients and carbon. The oceans function as a vast reservoir of dissolved organic matter (DOM), which contain...... extracellular enzymes as a key trait of the prokaryote-DOM interface. Understanding the chemical ecology of extracellular enzymes may reveal new insights to DOM cycling in the oceans....

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  4. Hydrolysis of organic matter during autoclaving of commingled household waste.

    Science.gov (United States)

    Papadimitriou, E K

    2010-04-01

    Commingled household waste (HW) that had a controlled composition was autoclaved at elevated pressures in the presence of saturated steam for one hour at the nominal temperature levels of 130 degrees C, 160 degrees C and 200 degrees C. The focus of this study was the impact of temperature/pressure on hydrolysis of organic matter during autoclaving and the extent of its hydrolysis. The pH decreased with autoclaving temperature with which it had a linear relationship, and ranged from 7.4 and 6 in floc, and 6.7 and 3.6 in steam condensate. Overall, organic matter solubilisation, as indicated by dissolved organic carbon, biological and chemical oxygen demands, and total dissolved solids, increased with temperature. Lignin did not appear to hydrolyse. Hemicellulose hydrolysed and degraded the most, followed by cellulose. The highest recoveries of hemicellulose and cellulose in solution were achieved at 160 degrees C, although the latter could be due to experimental error. The largest losses of hemicellulose and cellulose were recorded at 200 degrees C. The performance of the system in respect to hydrolysis was inferior compared to other hydrothermal systems, particularly those employing wet oxidation.

  5. Lead sequestration and species redistribution during soil organic matter decomposition

    Science.gov (United States)

    Schroth, A.W.; Bostick, B.C.; Kaste, J.M.; Friedland, A.J.

    2008-01-01

    The turnover of soil organic matter (SOM) maintains a dynamic chemical environment in the forest floor that can impact metal speciation on relatively short timescales. Here we measure the speciation of Pb in controlled and natural organic (O) soil horizons to quantify changes in metal partitioning during SOM decomposition in different forest litters. We provide a link between the sequestration of pollutant Pb in O-horizons, estimated by forest floor Pb inventories, and speciation using synchrotron-based X-ray fluorescence and X-ray absorption spectroscopy. When Pb was introduced to fresh forest Oi samples, it adsorbed primarily to SOM surfaces, but as decomposition progressed over two years in controlled experiments, up to 60% of the Pb was redistributed to pedogenic birnessite and ferrihydrite surfaces. In addition, a significant fraction of pollutant Pb in natural soil profiles was associated with similar mineral phases (???20-35%) and SOM (???65-80%). Conifer forests have at least 2-fold higher Pb burdens in the forest floor relative to deciduous forests due to more efficient atmospheric scavenging and slower organic matter turnover. We demonstrate that pedogenic minerals play an important role in surface soil Pb sequestration, particularly in deciduous forests, and should be considered in any assessment of pollutant Pb mobility. ?? 2008 American Chemical Society.

  6. Photobiogeochemistry of organic matter. Principles and practices in water environments

    Energy Technology Data Exchange (ETDEWEB)

    Mostofa, Khan M.G. [Chinese Academy of Sciences, Guiyang, Guizhou (China). Inst. of Geochemistry; Yoshioka, Takahito [Kyoto Univ. (Japan). Field Science Education; Mottaleb, M. Abdul [Northwest Missouri State Univ., MO (United States). Dept. of Chemistry and Physics; Vione, Davide (eds.) [Turin Univ. (Italy). Dipt. di Chimica Analitica

    2013-03-01

    Gives a comprehensive account of photo and biological processes of key biogeochemical functions and their interrelations in the aquatic environment. Discusses essential issues refering to the aquatic environment. Designed as a study text for students. Photoinduced processes, caused by natural sunlight, are key functions for sustaining all living organisms through production and transformation of organic matter (OM) in the biosphere. Production of hydrogen peroxide (H2O2) from OM is a primary step of photoinduced processes, because H2O2 acts as strong reductant and oxidant. It is potentially important in many aquatic reactions, also in association with photosynthesis. Allochthonous and autochthonous dissolved organic matter (DOM) can be involved into several photoinduced or biological processes. DOM subsequently undergoes several physical, chemical, photoinduced and biological processes, which can be affected by global warming. This book is uniquely structured to overview some vital issues, such as: DOM; H2O2 and ROOH; HO x; Degradation of DOM; CDOM, FDOM; Photosynthesis; Chlorophyll; Metal complexation, and Global warming, as well as their mutual interrelationships, based on updated scientific results''.

  7. Complexation of lead by organic matter in Luanda Bay, Angola.

    Science.gov (United States)

    Leitão, Anabela; Santos, Ana Maria; Boaventura, Rui A R

    2015-10-01

    Speciation is defined as the distribution of an element among different chemical species. Although the relation between speciation and bioavailability is complex, the metal present as free hydrated ion, or as weak complexes able to dissociate, is usually more bioavailable than the metal incorporated in strong complexes or adsorbed on colloidal or particulate matter. Among the analytical techniques currently available, anodic stripping voltammetry (ASV) has been one of the most used in the identification and quantification of several heavy metal species in aquatic systems. This work concerns the speciation study of lead, in original (natural, non-filtered) and filtered water samples and in suspensions of particulate matter and sediments from Luanda Bay (Angola). Complexes of lead with organics were identified and quantified by differential pulse anodic stripping voltammetry technique. Each sample was progressively titrated with a Pb(II) standard solution until complete saturation of the organic ligands. After each addition of Pb(II), the intensity, potential and peak width of the voltammetric signal were measured. The results obtained in this work show that more than 95 % of the lead in the aquatic environment is bound in inert organic complexes, considering all samples from different sampling sites. In sediment samples, the lead is totally (100 %) complexed with ligands adsorbed on the particles surface. Two kinds of dominant lead complexes, very strong (logK >11) and strong to moderately strong (8< logK <11), were found, revealing the lead affinity for the stronger ligands.

  8. Production of Dissolved Organic Matter During Fungal Wood Rot Decay

    Science.gov (United States)

    Filley, T. R.; Jellison, J.; Goodell, B.; Kelley, S.; Davis, M.

    2002-12-01

    Dissolved organic matter mediates numerous biogeochemical processes in soil systems impacting subsurface microbial activity, redox chemistry, soil structure, and carbon and nitrogen sequestration. The structure and chemistry of DOM is a function of the inherited chemistry of the source material, the type of microbial action that has occurred, and selective interaction with mineral substrates. The type of fungal decomposition imparted to woody tissue is a major factor in determining the nature of DOM in forest soils. In order to investigate the relationship between fungal decomposition and the nature of DOM in coniferous forest soils we conducted 32-week inoculation studies on spruce sapwood with basidiomycete brown-rot wood decay fungi where leachable dissolved and colloidal organic matter was separated from decayed residue. A detailed examination of the organic fractions was conducted using 13C-labeled tetramethylammonium hydroxide thermochemolysis, solid-state 13C-NMR, and electrospray mass spectrometry. The progressive stages of microbial decay (cellulolytic and ligninolytic) were manifested in the chemical composition of the DOM which showed an evolution from a composition initially polysaccharide rich to one dominated by mildly oxidized and demethylated lignin. Upon removal of all polysaccharides at 16 weeks the DOM (up to 10% by weight of the original tissue) looked chemically distinct from the degraded residue

  9. Mineral Associated Organic Matter: Plant Litter Compounds or Microbial Material?

    Science.gov (United States)

    Rumpel, C.

    2014-12-01

    Mineral interaction may affect the stabilisation of plant litter directly or indirectly after microbial decomposition and transformation. The importance of both organic matter sources may vary within the soil profile. This talk will synthesize recent work on the composition of mineral associated material in top- as well as subsoil horizons. We used density fractionation to isolate the mineral-associated fraction and characterised their composition by elemental analyses, NMR spectroscopy, analytical pyrolysis as well as nanoSIMS. Our results showed enrichment of mineral associated organic matter in subsoil horizons. However, material derived from new plant litter may be stabilised at similar rates in top- and subsoil horizons. N-containing compounds are enriched in the mineral associated fraction of subsoil horizons, indicating enrichment of microbial derived material with depth. Nano scale analyses showed that indeed plant-derived material may be associated with metal oxides in topsoil horizons, whereas the mineral associated organic matter in subsoil horizons may consist of microbial cells. Our results indicate that the nature of OM stabilised by mineral interactions is depth specific. Therefore, we suggest, that plant derived lignocellulosic material may be preserved by mineral interactions in topsoil given its incomplete degradation, thereby leading to the formation of functional groups and favouring adsorption to soil minerals. This is consistent with the higher state of lignin-degradation observed in topsoil horizons as compared to subsoil. At depth, where microorganisms are most likely energy limited, degradation of fresh plant litter may be complete, thereby diminishing the formation of lignocellulosic compounds capable of sorption onto metal oxides. As a result stabilised OM may consist primarily of microbial cells. Thus our study is consistent with the microbial efficiency-matrix stabilisation (MEMS) hypothesis, which says that microbial use efficiency

  10. Priming of soil organic matter decomposition in cryoturbated Arctic soils

    Science.gov (United States)

    Richter, A.; Wild, B.; Schnecker, J.; Rusalimova, O.

    2012-12-01

    The Arctic is subjected to particularly high rates of warming, with profound consequences for the carbon cycle: on the one hand plant productivity and C storage in plant biomass have been shown to increase strongly in many parts of the Arctic, on the other hand, increasing rates of soil organic matter (SOM) decomposition have been reported. One of the possibilities that could reconcile these observations is, that increased plant growth may lead to increased root exudation rates, which are known to stimulate microbial turnover of organic matter under certain circumstances, in a process termed "priming" of SOM. Two mechanisms have been brought forward that may be responsible for priming: first, easily assimilable material exuded by plant roots may help microbes to overcome their energy limitation and second, this input of labile carbon could lead to a nitrogen limitation of the microbial community and lead to nitrogen mining, i.e. decomposition of N-rich SOM. We here report on an incubation study with arctic soil investigating potential priming of SOM decomposition in organic topsoil horizons, cryoturbated organic matter and subsoil mineral horizons of tundra soil from the Taymyr peninsula in Siberia. We used arctic soils, that are characterized by cryoturbation (mixing of soil layers due to freezing and thawing), for this study. Turbated cryosols store more than 580 Gt C globally, a significant proportion of which is stored in the cryoturbated organic matter. We hypothesized that an increased availability of labile compounds would increase SOM decomposition rates, and that this effect would be strongest in horizons with a low natural availability of labile C, i.e. in the mineral subsoil. We amended soils with 13C labelled glucose, cellulose, amino acids or proteins, and measured the mineralization of SOM C as well as microbial community composition and potential activities of extracellular enzymes. Our results demonstrate that topsoil organic, cryoturbated and

  11. Global effects of agriculture on fluvial dissolved organic matter

    DEFF Research Database (Denmark)

    Graeber, Daniel; Boëchat, Iola; Encina, Francisco;

    2015-01-01

    (DOM), which constitutes the main vector of carbon transport from soils to fluvial networks and to the sea, and is involved in a large variety of biogeochemical processes. Here, we provide first evidence about the wider occurrence of agricultural impacts on the concentration and composition of fluvial...... the reactivity of catchment DOM emissions, thereby fuelling the biogeochemical processing in fluvial networks, and resulting in higher ecosystem productivity and CO2 outgassing.......Agricultural land covers approximately 40% of Earth’s land surface and affects hydromorphological, biogeochemical and ecological characteristics of fluvial networks. In the northern temperate region, agriculture also strongly affects the amount and molecular composition of dissolved organic matter...

  12. Persistence of soil organic matter as an ecosystem property

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, M.W.; Torn, M. S.; Abiven, S.; Dittmar, T.; Guggenberger, G.; Janssens, I.A.; Kleber, M.; Kögel-Knabner, I.; Lehmann, J.; Manning, D.A.C.; Nannipieri, P.; Rasse, D.P.; Weiner, S.; Trumbore, S.E.

    2011-08-15

    Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily—and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.

  13. Aquatic Organic Matter Fluorescence - from phenomenon to application

    Science.gov (United States)

    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

  14. Conservative or reactive? Mechanistic chemical perspectives on organic matter stability

    Science.gov (United States)

    Koch, Boris

    2016-04-01

    Carbon fixation by terrestrial and marine primary production has a fundamental seasonal effect on the atmospheric carbon content and it profoundly contributes to long-term carbon storage in form of organic matter (OM) in soils, water, and sediments. The efficacy of this sequestration process strongly depends on the degree of OM persistence. Therefore, one of the key issues in dissolved and particulate OM research is to assess the stability of reservoirs and to quantify their contribution to global carbon fluxes. Incubation experiments are helpful to assess OM stability during the first, early diagenetic turnover induced by sunlight or microbes. However, net carbon fluxes within the global carbon cycle also act on much longer time scales, which are not amenable in experiments. It is therefore critical to improve our mechanistic understanding to be able to assess potential future changes in the organic matter cycle. This session contribution highlights some achievements and open questions in the field. An improved mechanistic understanding of OM turnover particularly depends on the molecular characterization of biogeochemical processes and their kinetics: (i) in soils and sediments, aggregation/disaggregation of OM is primarily controlled by its molecular composition. Hence, the chemical composition determines the transfer of organic carbon from the large particulate to the small dissolved organic matter reservoir - an important substrate for microbial metabolism. (ii) In estuaries, dissolved organic carbon gradients usually suggest conservative behavior, whereas molecular-level studies reveal a substantial chemical modification of terrestrial DOM along the land-ocean interface. (iii) In the ocean, previous studies have shown that the recalcitrance of OM depends on bulk concentration and energy yield. However, ultrahigh resolution mass spectrometry in combination with radiocarbon analyses also emphasized that stability is tightly connected to molecular composition

  15. Transformation of terrestrial organic matter along thermokarst-affected permafrost coasts in the Arctic.

    Science.gov (United States)

    Tanski, George; Lantuit, Hugues; Ruttor, Saskia; Knoblauch, Christian; Radosavljevic, Boris; Strauss, Jens; Wolter, Juliane; Irrgang, Anna M; Ramage, Justine; Fritz, Michael

    2017-03-01

    The changing climate in the Arctic has a profound impact on permafrost coasts, which are subject to intensified thermokarst formation and erosion. Consequently, terrestrial organic matter (OM) is mobilized and transported into the nearshore zone. Yet, little is known about the fate of mobilized OM before and after entering the ocean. In this study we investigated a retrogressive thaw slump (RTS) on Qikiqtaruk - Herschel Island (Yukon coast, Canada). The RTS was classified into an undisturbed, a disturbed (thermokarst-affected) and a nearshore zone and sampled systematically along transects. Samples were analyzed for total and dissolved organic carbon and nitrogen (TOC, DOC, TN, DN), stable carbon isotopes (δ(13)C-TOC, δ(13)C-DOC), and dissolved inorganic nitrogen (DIN), which were compared between the zones. C/N-ratios, δ(13)C signatures, and ammonium (NH4-N) concentrations were used as indicators for OM degradation along with biomarkers (n-alkanes, n-fatty acids, n-alcohols). Our results show that OM significantly decreases after disturbance with a TOC and DOC loss of 77 and 55% and a TN and DN loss of 53 and 48%, respectively. C/N-ratios decrease significantly, whereas NH4-N concentrations slightly increase in freshly thawed material. In the nearshore zone, OM contents are comparable to the disturbed zone. We suggest that the strong decrease in OM is caused by initial dilution with melted massive ice and immediate offshore transport via the thaw stream. In the mudpool and thaw stream, OM is subject to degradation, whereas in the slump floor the nitrogen decrease is caused by recolonizing vegetation. Within the nearshore zone of the ocean, heavier portions of OM are directly buried in marine sediments close to shore. We conclude that RTS have profound impacts on coastal environments in the Arctic. They mobilize nutrients from permafrost, substantially decrease OM contents and provide fresh water and nutrients at a point source.

  16. Biogeochemistry of dissolved organic matter in an anoxic intertidal creek bank

    Science.gov (United States)

    Seidel, Michael; Beck, Melanie; Riedel, Thomas; Waska, Hannelore; Suryaputra, I. G. N. A.; Schnetger, Bernhard; Niggemann, Jutta; Simon, Meinhard; Dittmar, Thorsten

    2014-09-01

    Seawater circulation in permeable coastal sediments is driven by tidal changes in hydraulic gradients. The resulting submarine groundwater discharge is a source of nutrients and dissolved organic matter (DOM) to the water column. Yet, little is known about the cycling of DOM within tidal sediments, because the molecular DOM characterization remains analytically challenging. One technique that can dissect the multitude of molecules in DOM is ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). To aim at a high resolution DOM analysis we study the seasonal turnover and marine and terrestrial sources of DOM in an intertidal creek bank of the southern North Sea down to 3 m depth and link the biogeochemical processes to FT-ICR-MS data and the analyses of inorganic porewater chemistry, δ13C of solid-phase extracted dissolved organic carbon (SPE-DOC), dissolved black carbon (DBC) and dissolved carbohydrates (DCHO). Increasing concentrations of dissolved Fe, Mn, P, total alkalinity, dissolved nitrogen, DOC and a concomitant decrease of sulfate along the seawater circulation path from the upper tidal flat to the tidal flat margin indicate continuous microbial activity. The relative increase of Si concentrations, unsaturated aliphatics, peptide molecular formulae and isotopically more 13C-enriched SPE-DOC towards the tidal flat margin suggests that remineralization processes mobilize DOM from buried algal (diatoms) and microbial biomass. Porewater in sediments ocean. Porewater DOM accumulating at the low water line is enriched in N and S. We hypothesize that this is partly due to DOM reacting with dissolved sulfide and ammonium which may increase the refractory character of the DOM, hence making it less bioavailable for in situ active microbes.

  17. Soil Organic Matter Map of Europe. Estimates of soil organic matter content of the topsoil of FAO-Unesco soil units

    NARCIS (Netherlands)

    Fraters B; Bouwman AF; Thewessen TJM

    1993-01-01

    One of the threats to groundwater is the leaching of pesticides. A major factor determining the migration of most pesticides in soil is their organic matter content. Using classification criteria, data on organic matter content in European and American soil profiles are described, and common knowled

  18. Soil Organic Matter Map of Europe. Estimates of soil organic matter content of the topsoil of FAO-Unesco soil units

    NARCIS (Netherlands)

    Fraters B; Bouwman AF; Thewessen TJM

    1993-01-01

    One of the threats to groundwater is the leaching of pesticides. A major factor determining the migration of most pesticides in soil is their organic matter content. Using classification criteria, data on organic matter content in European and American soil profiles are described, and common knowl

  19. Ironing out the details of soil organic matter cycling: The unique role of Fe-bearing minerals in regulating organic matter transformation in soils

    Science.gov (United States)

    Heckman, K. A.; Lawrence, C. R.; Harden, J. W.; Crate, J.; Swanston, C.

    2015-12-01

    Interest in the influence of mineral chemistry on soil organic matter cycling has been steadily growing, with the role of iron specifically garnering a great deal of attention. Empirical evidence from both lab and field based studies suggest that the interactions of Fe-bearing minerals and colloidal Fe species are unique from the interactions of the soil mineral matrix as a whole and may have a disproportionate influence on soil organic matter. We present results from a suite of studies examining Fe-organic matter interactions which utilize a broad range of technical approaches and highlight the use of radiocarbon analysis in terrestrial carbon cycle studies. Data suggests that interaction of organics with Fe-bearing moieties induces consistent partitioning of organics between dissolved and surface bound organic matter pools, including significant consequences for N and P availability and biodegradability of soil organic matter. Selective dissolution techniques have revealed that Fe-humus complexes comprise a significant pool of soil organic matter which cycles on a shorter-term basis across a variety of ecosystems types, while sequential density separation combined with x-ray diffraction imply concentration and long-term preservation of N-rich organics on Fe-bearing crystalline mineral surfaces. Our results explore the unique and multifaceted roles of Fe in regulating organic matter transformation and preservation in a range of soil types.

  20. Degradation of organic matter in the sediments of Hongfeng Reservoir

    Institute of Scientific and Technical Information of China (English)

    WEI Zhongqing; LIU Congqiang; LIANG Xiaobing; WANG Fushun; WANG Shaofeng

    2005-01-01

    In this work, the distribution of organic carbon, DNA and lipids in the sediments of Hongfeng Reservoir were described in addition to SO42- Profile in pore water. The contents of organic carbon in the sediments range from 23.3 to 76.8 mg·g-1, with the peak value appearing at the depth of 8 cm bellow the sediments water interface (SWI), and tend to decrease gradually with sedimentation depth. The concentrations of SO42- Decreased from 40.50 mg·L-1 to 12.00 mg·L-1 at SWI in top 4 cm sediment, and was kept at 12.0 mg·L-1 bellow that depth. Newly produced organic carbon can be conserved as long as 14 years in the sediments. The contents of DNA were relatively high in top 9 cm surface sediments, as revealed by agarose gel images, close to those of organic carbon and sulphate reduction index (SRI). This study shows that bacteria played an important role in organic matter degradation; SO42- is the primary electron acceptor under anaerobic condition in this reservoir; DNA in the lake sediments can provide important information for the study of cycling of nutrient elements in the lake.

  1. Thermal Evolution of Organic Matter and Secondary Hydrocarbon Generation from Upper Paleozoic Coal Deposits in Northern China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The metamorphism and hydrocarbon generation from the Upper Paleozoic coal-bearing strata in Northern China have been widely studied by Chinese geologists since the 1990s.Based on a large amount of data of Ro values, combined with geological background, we have systematically analyzed the thermal evolutionary characteristics of organic matter and the stages of hydrocarbon generation from the Permo-Carboniferous coal deposits and discussed the condition of secondary hydrocarbon generation.The distribution range of secondary hydrocarbon generation in Northern China is thus determined.It is shown that the coal ranks of the Upper Paleozoic coal deposits are higher in the southern and western belts than those in the northern and eastern belts.Really significant secondary hydrocarbon generation is mainly related to the thermal evolution of organic matter during the Himalayan Period.Profitable areas for secondary hydrocarbon generation should be buried at 3000-4000 m up to the present.Maturity of the Permo-Carboniferous source rocks is not very high.It is suggested that the Bohai Bay depression is favourable for secondary hydrocarbon generation and has good oil and gas prospects.

  2. Global effects of agriculture on fluvial dissolved organic matter

    DEFF Research Database (Denmark)

    Graeber, Daniel; Boëchat, Iola; Encina, Francisco

    2015-01-01

    Agricultural land covers approximately 40% of Earth’s land surface and affects hydromorphological, biogeochemical and ecological characteristics of fluvial networks. In the northern temperate region, agriculture also strongly affects the amount and molecular composition of dissolved organic matter...... (DOM), which constitutes the main vector of carbon transport from soils to fluvial networks and to the sea, and is involved in a large variety of biogeochemical processes. Here, we provide first evidence about the wider occurrence of agricultural impacts on the concentration and composition of fluvial...... DOM across climate zones of the northern and southern hemispheres. Both extensive and intensive farming altered fluvial DOM towards a more microbial and less plant-derived composition. Moreover, intensive farming significantly increased dissolved organic nitrogen (DON) concentrations. The DOM...

  3. Nature and transformation of dissolved organic matter in treatment wetlands

    Science.gov (United States)

    Barber, L.B.; Leenheer, J.A.; Noyes, T.I.; Stiles, E.A.

    2001-01-01

    This investigation into the occurrence, character, and transformation of dissolved organic matter (DOM) in treatment wetlands in the western United States shows that (i) the nature of DOM in the source water has a major influence on transformations that occur during treatment, (ii) the climate factors have a secondary effect on transformations, (iii) the wetlands receiving treated wastewater can produce a net increase in DOM, and (iv) the hierarchical analytical approach used in this study can measure the subtle DOM transformations that occur. As wastewater treatment plant effluent passes through treatment wetlands, the DOM undergoes transformation to become more aromatic and oxygenated. Autochthonous sources are contributed to the DOM, the nature of which is governed by the developmental stage of the wetland system as well as vegetation patterns. Concentrations of specific wastewaterderived organic contaminants such as linear alkylbenzene sulfonate, caffeine, and ethylenediaminetetraacetic acid were significantly attenuated by wetland treatment and were not contributed by internal loading.

  4. Dissolved Organic Matter in the Yukon River Basin

    Science.gov (United States)

    Aiken, G.; Striegl, R.; Schuster, P.

    2004-12-01

    Source materials, watershed geochemistry, oxidative processes and hydrology exert strong influences on the nature and reactivity of dissolved organic matter (DOM) in aquatic systems. At present, a critical question in carbon cycling is how climate change could alter the fate and chemical nature of dissolved organic carbon (DOC) released from watersheds, particularly those underlain by permafrost, and transported to rivers, lakes, estuaries and coastal waters. The spatial and temporal variability of DOM in surface waters associated with the Yukon River are being studied to better define processes controlling DOM in this system. Like many northern ecosystems, the Yukon River Basin is experiencing melting permafrost, drying of upland soils and changing wetland environments. Study results indicate that the transport of DOM in the river and its major tributaries is strongly seasonally dependent. Specific ultraviolet absorbance (SUVA) data, an excellent indicator of aromatic carbon content of DOM, also indicate a large variation in the chemical nature of the organic matter transported by the river. Lowest DOC concentrations and SUVA values were observed for samples collected in the winter under low flow conditions and for tributaries dominated by ground water inputs. Greatest DOC concentrations and SUVA values were measured on samples collected during the spring on the leading part of the hydrograph. High SUVA values are indicative of greater amounts of organic material originating from higher plants that are present in upper soil horizons and wetlands of the watershed. Aquatic humic substances collected from the Yukon River during the snowmelt period were found to have low nitrogen contents and greater amounts of aromatic C relative to samples from other aquatic environments. Low N content and high aromaticity are indicative of humic substances evolved from higher plant sources with little alteration resulting from microbial degradation or soil interactions. In addition

  5. Were the 2.1-Gyr fossil colonial organisms discovered in the Francevillian basin (Palaeoproterozoic, Gabon) buried by turbidites?

    Science.gov (United States)

    Parize, Olivier; Feybesse, Jean-Louis; Guillocheau, François; Mulder, Thierry

    2013-02-01

    The Francevillian series (Gabon) in which the Earth's oldest large colonial organisms were recently discovered (El Albani et al., 2010) were deposited 2 Gyr ago. These series are usually interpreted as a fining-upward basin-fill sequence composed by five superimposed lithological terms noted FA to FE. New studies initiated by AREVA, allowed new data to be collected on the southwestern edge of the Francevillian basin, particularly on newly excavated outcrops. Facies interpretations show that the Poubara sandstones and associated shales and black shales (upper part of FB,FB2a), correspond to turbidites deposited on an upper slope rather than one a shelf, submitted to tidal currents or storm wave action. These new interpretations based on facies association, sedimentary geometries, and basin evolution show that the depositional environment could be a turbidite lobe set at a palaeobathymetry deeper than 200 m.

  6. Nature of water molecular bridging of the soil organic matter

    Science.gov (United States)

    Kucerik, Jiri; Siewert, Christian; Quilesfogel-Esparza, Claudia; Schaumann, Gabriele E.

    2014-05-01

    Soil is a complex anisotropic and porous system consisting of both inorganic and organic parts, air and water, inhabited and successively transformed by soil biota. Processes of soil formation are influenced by several factors. Among the most important factors belong the inorganic and organic input materials, which are mixed and transformed during soil formation. As a result, specific interactions and interrelationships develop between soil compartments. Although, they are important for soil function and its stability, they are still not well understood. This work deals with water molecule bridges (WaMB), as one of those interactions, and their relation to organic matter functioning. Differential scanning calorimetry (DSC) belongs to the family of methods of thermal analysis, i.e. it uses heat as a probe of the sample's nature. In soil science, the application of this common method is quite rare. In our previous works, DSC revealed a physical stabilization of organic matter segments in soils by development of WaMB. Results suggested the development of those bridges at ambient temperature accompanied with condensation of water into small nanodroplets. In another work, we found out that water, evaporating at the same temperature as WaMB transition occurs, correlates with the activity of soil microorganisms measured via CO2respiration. In this work, the enthalpy and kinetic parameters of water evaporation are studied in two kinds of soil: in clay-rich chernozem soils originating from Siberia and a histosol collected in Germany. We discuss the details of application of DSC, experimental arrangement and advantages and disadvantages of this approach. It is shown that enthalpy of evaporation can be used for understanding the nature of water binding in soils with well-developed aggregates. In contrast, the evaporation of water from histosol, without a typical soil texture, is more complicated because of diffusion processes. Further, the connection between enthalpy of

  7. Thermodynamics of phenanthrene partition into solid organic matter from water

    Institute of Scientific and Technical Information of China (English)

    CHEN Bao-liang; ZHU Li-zhong; TAO Shu

    2005-01-01

    The thermodynamic behavior of organic contaminants in soils is essential to develop remediation technologies and assess risk from alternative technologies. Thermodynamics of phenanthrene partition into four solids (three soils and a bentonite) from water were investigated. The thermodynamics parameters (Δ H, Δ G°, Δ S°, ) were calculated according to experimental data. The total sorption heats of phenanthrene to solids from water ranged from - 7.93 to - 17.1 kJ/mol, which were less exothermic than the condensation heat of phenanthrene-solid(i.e., - 18.6 k J/mol). The partition heats of phenanthrene dissolved into solid organic matter ranged from 23.1 to 32.2k J/mol, which were less endothermic than the aqueous dissolved heat of phenanthrene(i. e., 40.2 kJ/mol), and were more endothermic than the fusion heat of phenanthrene-solid (i. e., 18.6 kJ/mol). The standard free energy changes, Δ G°, are all negative which suggested that phenanthrene sorption into solid was a spontaneous process. The positive values of standard entropy changes,ΔS° , show a gain in entropy for the transfer of phenanthrene at the stated standard state. Due to solubility-enhancement of phenanthrene,the partition coefficients normalized by organic carbon contents decrease with increasing system temperature(i. e., In Koc = -0.284In S +9.82( n =4, r2 = 0.992)). The solubility of phenanthrene in solid organic matter increased with increasing temperatures. Transports of phenanthrene in different latitude locations and seasons would be predicted according to its sorption thermodynamics behavior.

  8. Dissolved organic matter photolysis in Canadian arctic thaw ponds

    Science.gov (United States)

    Laurion, Isabelle; Mladenov, Natalie

    2013-09-01

    The abundant thaw lakes and ponds in the circumarctic receive a new pool of organic carbon as permafrost peat soils degrade, which can be exposed to significant irradiance that potentially increases as climate warms and ice cover shortens. Exposure to sunlight is known to accelerate the transformation of dissolved organic matter (DOM) into molecules that can be more readily used by microbes. We sampled the water from two common classes of ponds found in the ice-wedge system of continuous permafrost regions of Canada, polygonal and runnel ponds, and followed the transformation of DOM over 12 days by looking at dissolved organic carbon (DOC) concentration and DOM absorption and fluorescence properties. The results indicate a relatively fast decay of color (3.4 and 1.6% loss d-1 of absorption at 320 nm for the polygonal and runnel pond, respectively) and fluorescence (6.1 and 8.3% loss d-1 of total fluorescent components, respectively) at the pond surface, faster in the case of humic-like components, but insignificant losses of DOC over the observed period. This result indicates that direct DOM mineralization (photochemical production of CO2) is apparently minor in thaw ponds compared to the photochemical transformation of DOM into less chromophoric and likely more labile molecules with a greater potential for microbial mineralization. Therefore, DOM photolysis in arctic thaw ponds can be considered as a catalytic mechanism, accelerating the microbial turnover of mobilized organic matter from thawing permafrost and the production of greenhouse gases, especially in the most shallow ponds. Under a warming climate, this mechanism will intensify as summers lengthen.

  9. Speciation of The Particulate Organic Matter In Three Remote Areas

    Science.gov (United States)

    Masclet, Pierre; Marchand, Nicolas; Jaffrezo, Jean Luc; Besombes, Jean Luc

    Total particulate matter was collected as part of three programs between 1999 and 2001 (EAAS in Finland, ESOMPTE in Marseille/Fos and POVA in french alpine valleys). The speciation of the particulate organic matter (POM) was performed by Gas Chromatography or HPLC coupled with a mass spectrometer. 13 organic families were identified in the 245 samples collected. The presence of some functional groups (- COOH; - OH and - CHO) and the carbon chain length are used in order to identify the sources of the particulate pollutants and the physicochemical behaviour during the long range atmospheric transport of the aerosol. The composition of the POM differs depending on the season (the secondary fraction reaches 27 % in summer and only 6% in winter) and on the remoteness of the sources. Alkanes are always the most abundant compounds. Polycyclic aromatic hydrocarbons, alcohols, esters, carboxylic acids and monoaromatic hydrocarbons are present in significant abundance. Some alkenes, aldehydes, ether oxydes, ketones and halocompounds are also found. Alcohols are more abundant in aerosols collected close to marine sites. Long carbon chain esters are mostly found in aerosols collected in high density vegetation areas and relatively high concentrations of PAH are measured in aerosols collected close to highly populated areas. These three families are good geochemical tracers, respectively of marine, biogenic and anthropic sources.

  10. Terrestrial and marine perspectives on modeling organic matter degradation pathways.

    Science.gov (United States)

    Burd, Adrian B; Frey, Serita; Cabre, Anna; Ito, Takamitsu; Levine, Naomi M; Lønborg, Christian; Long, Matthew; Mauritz, Marguerite; Thomas, R Quinn; Stephens, Brandon M; Vanwalleghem, Tom; Zeng, Ning

    2016-01-01

    Organic matter (OM) plays a major role in both terrestrial and oceanic biogeochemical cycles. The amount of carbon stored in these systems is far greater than that of carbon dioxide (CO2 ) in the atmosphere, and annual fluxes of CO2 from these pools to the atmosphere exceed those from fossil fuel combustion. Understanding the processes that determine the fate of detrital material is important for predicting the effects that climate change will have on feedbacks to the global carbon cycle. However, Earth System Models (ESMs) typically utilize very simple formulations of processes affecting the mineralization and storage of detrital OM. Recent changes in our view of the nature of this material and the factors controlling its transformation have yet to find their way into models. In this review, we highlight the current understanding of the role and cycling of detrital OM in terrestrial and marine systems and examine how this pool of material is represented in ESMs. We include a discussion of the different mineralization pathways available as organic matter moves from soils, through inland waters to coastal systems and ultimately into open ocean environments. We argue that there is strong commonality between aspects of OM transformation in both terrestrial and marine systems and that our respective scientific communities would benefit from closer collaboration.

  11. Soil Organic Matter Mapping by Decision Tree Modeling

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bin; ZHANG Xing-Gang; WANG Fan; WANG Ren-Chao

    2005-01-01

    Based on a case study of Longyou County, Zhejiang Province, the decision tree, a data mining method, was used to analyze the relationships between soil organic matter (SOM) and other environmental and satellite sensing spatial data.The decision tree associated SOM content with some extensive easily observable landscape attributes, such as landform,geology, land use, and remote sensing images, thus transforming the SOM-related information into a clear, quantitative,landscape factor-associated regular system. This system could be used to predict continuous SOM spatial distribution.By analyzing factors such as elevation, geological unit, soil type, land use, remotely sensed data, upslope contributing area, slope, aspect, planform curvature, and profile curvature, the decision tree could predict distribution of soil organic matter levels. Among these factors, elevation, land use, aspect, soil type, the first principle component of bitemporal Landsat TM, and upslope contributing area were considered the most important variables for predicting SOM. Results of the prediction between SOM content and landscape types sorted by the decision tree showed a close relationship with an accuracy of 81.1%.

  12. Photochemical and Nonphotochemical Transformations of Cysteine with Dissolved Organic Matter.

    Science.gov (United States)

    Chu, Chiheng; Erickson, Paul R; Lundeen, Rachel A; Stamatelatos, Dimitrios; Alaimo, Peter J; Latch, Douglas E; McNeill, Kristopher

    2016-06-21

    Cysteine (Cys) plays numerous key roles in the biogeochemistry of natural waters. Despite its importance, a full assessment of Cys abiotic transformation kinetics, products and pathways under environmental conditions has not been conducted. This study is a mechanistic evaluation of the photochemical and nonphotochemical (dark) transformations of Cys in solutions containing chromophoric dissolved organic matter (CDOM). The results show that Cys underwent abiotic transformations under both dark and irradiated conditions. Under dark conditions, the transformation rates of Cys were moderate and were highly pH- and temperature-dependent. Under UVA or natural sunlight irradiations, Cys transformation rates were enhanced by up to two orders of magnitude compared to rates under dark conditions. Product analysis indicated cystine and cysteine sulfinic acid were the major photooxidation products. In addition, this study provides an assessment of the contributions of singlet oxygen, hydroxyl radical, hydrogen peroxide, and triplet dissolved organic matter to the CDOM-sensitized photochemical oxidation of Cys. The results suggest that another unknown pathway was dominant in the CDOM-sensitized photodegradation of Cys, which will require further study to identify.

  13. Seasonal changes in photochemical properties of dissolved organic matter

    Science.gov (United States)

    Porcal, P.; Dillon, P. J.; Molot, L. A.

    2013-03-01

    The fate of dissolved organic matter (DOM) in lakes and streams is significantly affected by photochemical transformation of DOM. A series of laboratory photochemical experiments was conducted to describe long-term changes in photochemical properties of DOM. The stream samples used in this study originated from three different catchments on the southern-most part of the Boreal ecozone near Dorset, Ontario, Canada. A first-order kinetics equation was used to model photochemical degradation of DOM and the kinetic rate constant, K, was used as an indicator of photochemical properties of DOM. Highest Kwas observed in samples from the catchment dominated by coniferous forest while the lowest K was measured in the deciduous catchment. Kinetic rate constants from all three catchments showed a sinusoidal pattern during the hydrological year. K increased steadily during autumn and winter and decreased during spring and summer. The highest values were observed during spring melt events when DOM was flushed from terrestrial sources by high flows. The minimum rate constants were found in summer when discharge was lowest. DOM molecular weight and specific absorbance at 254 nm also exhibited annual cycles corresponding to the seasonal cycles of terrestrial organic matter but the relationships between these properties and K was probably affected by previous exposure to solar radiation during transit from the catchment as well as pH and iron.

  14. Effect of organic fertilizers derived dissolved organic matter on pesticide sorption and leaching

    Energy Technology Data Exchange (ETDEWEB)

    Li Kun [Department of Plant, Soil, and Insect Sciences, Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States); Xing Baoshan [Department of Plant, Soil, and Insect Sciences, Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States) and Northeast Institute of Geography and Agro-ecology, CAS, Harbin 150040 (China)]. E-mail: bx@pssci.umass.edu; Torello, William A. [Department of Plant, Soil, and Insect Sciences, Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States)

    2005-03-01

    Incorporation of organic fertilizers/amendments has been, and continues to be, a popular strategy for golf course turfgrass management. Dissolved organic matter (DOM) derived from these organic materials may, however, facilitate organic chemical movement through soils. A batch equilibrium technique was used to evaluate the effects of organic fertilizer-derived DOM on sorption of three organic chemicals (2,4-D, naphthalene and chlorpyrifos) in USGA (United States Golf Association) sand, a mixed soil (70% USGA sand and 30% native soil) and a silt loam soil (Typic Fragiochrept). DOM was extracted from two commercial organic fertilizers. Column leaching experiments were also performed using USGA sand. Sorption experiments showed that sorption capacity was significantly reduced with increasing DOM concentration in solution for all three chemicals. Column experimental results were consistent with batch equilibrium data. These results suggest that organic fertilizer-derived DOM might lead to enhanced transport of applied chemicals in turf soils. - Dissolved organic matter could result in enhanced transport of chemicals applied to turf.

  15. ORGANIC CARBON AND TOTAL NITROGEN IN THE DENSIMETRIC FRACTIONS OF ORGANIC MATTER UNDER DIFFERENT SOIL MANAGEMEN

    Directory of Open Access Journals (Sweden)

    MARCELO RIBEIRO VILELA PRADO

    2016-01-01

    Full Text Available The evaluation of land use and management by the measurement of soil organic matter and its fractions has gained attention since it helps in the understanding of the dynamics of their contribution to soil productivity, especially in tropical environments. This study was conducted in the municipality of Colorado do Oeste, state of Rondônia, Brazil and its aim was to determinethe quantity of organic carbon and total nitrogen in the light and heavy fractions of organic matter in the surface layers of a typic hapludalf under different land use systems: Native Forest: open evergreen forest, reference environment; Agroforestry System 1: teak (Tectona grandis LF and kudzu (Pueraria montana; Agroforestry System 2: coffee (Coffea canephora, marandu palisade grass (Brachiaria brizantha cv. Marandu, “pinho cuiabano” (Parkia multijuga, teak and kudzu.; Agroforestry System 3: teak and cocoa (Theobroma cacao; Silvopasture System: teak, cocoa and marandu palisade grass; and Extensive Grazing System: marandu palisade grass. The experimental design was a randomized block in split-split plots (use systems versus soil layers of 0-0.05 and 0.05-0.10 m with three replications. The results showed that relative to Native Forest, the Agroforestry System 2 had equal- and greater amounts of organic carbon and total nitrogen respectively (light and heavy fractions in the soil organic matter, with the light fraction being responsible for storage of approximately 45% and 70% of the organic carbon and total nitrogen, respectively. Therefore, the light densimetric fraction proved to be useful in the early identification of the general decline of the soil organic matter in the land use systems evaluated.

  16. Origin of sedimentary organic matter at the Northern Cascadia Margin

    Science.gov (United States)

    Kaneko, M.; Naraoka, H.

    2007-12-01

    Gas hydrate in marine sediments may have important roles on global carbon cycle and climatic change. We examined origins of sedimentary organic matter and bacterial activity in deep and hydrate-bearing sediment cored in Site U1327 and U1328 at northern Cascadia Margin by IODP Exp311, using σ13C of total organic carbon (TOC), σ15N of total nitrogen (TN), σ34S of total sulfur (TS), and σ13C of biomarkers in hydrocarbon fraction. In both sites, TOC/TN ratios and σ13C of TOC values ranged from 5.5 to 18.0 and -25.7 to -21.5 ‰, respectively, suggesting that sedimentary organic matter is a mixture of terrestrial and marine sources. Long chain (n)-alkanes (C27, C29, and C30), known as biomarkers of terrestrial higher plant were most abundant components (up to ~50 μg/gCorg) through down to 300 mbsf, and their σ13C values (-34.3 to -28.7 ‰) reveal their C3 plant origin. In addition, very long-chain alkene (C37) occurred in some sediments, which suggests the blooming by coccolithophore in the past. σ34S of TS values at both sites show large variation between -30 to +20 ‰. Most of σ34S of TS values were less than present σ34S value of seawater sulfate (+20.3 ‰). This is attributable to isotope fractionation during microbial sulfate reduction. Crocetenes including one double bond occurred in deep sediments with higher σ13C values (-23 ‰) than the reported σ13C values (< ~ -100 ‰, Elvert et al, 2000), providing possibility of heterotrophic archaea using marine organic matter as a carbon source. Pentamethylicosane (PMI) was detected in relatively high concentrations at 249 mbsf at Site U1328 and its σ13C value was -46.4 ‰. This PMI could be chemoautotrophic archaea in origin such as methanogen. Diploptene was also detected in most sediments with the σ13C value of -37 to -35 ‰, probably being characteristic of chemoautotrophic bacteria.

  17. Kinetics of Organic Matter Biodegradation in Leachate from Tobacco Waste

    Directory of Open Access Journals (Sweden)

    Briški, F.

    2012-09-01

    Full Text Available Treatment of wastes and leachate evolved in landfills is today an imperative due to rigorous environmental protection legislation. In this work, biodegradation of the organic fraction in tobaccowaste leachate was studied. Experiments were carried out in a batch reactor at initial concentra tion of activated sludge of 3.03 g dm–3 and different initial concentrations of organic matter in leachate, expressed as COD, which ranged from 0.5 to 3.0 g dm–3 . The working volume of the reactor (Fig. 1 was 7 dm3 within the cylindrical porous liner and it was filled with the suspension of leachate and activated sludge . The liner was designed such that it did not allow activated sludge to pass through. Continuous up-flow aeration was provided by a membrane pump. The temperature during the biodegradation process was 23 ± 2 °C. Dissolved oxygen, pH and temperature in reactor were monitored continuously by probes connected to a remote meter. Toxicity of leachate was performed by toxicity test using marine bacteria Vibrio fischeri before starting with the biodegradation in the batch reactor. The obtained results showed that effective concentration of leachate is EC 50 = 1.6 g dm–3 and toxicity impact index is TII50 = 9.99, meaning that untreated leachate must not be discharged into the environment before treatment. The results of the biodegradation process of leachate in batch reactor are presented in Table 1 and Fig. 2. The ratio γXv/γX was almost constant throughout the experiments and ranged from 0.69 do 0.73. This implies that the concentration of biomass remained unchanged during the experiments, and average yield was 5.26 %. The important kinetic and stoichiometric parameters required for performance of the biological removal process, namely the Y, Ks, Kd, and μmax were calculated from the batch experiments (Table 2. The experimental results of the influence of initial substrate concentrations on substrate degradation rate, and influence of

  18. Potential enzyme activities in cryoturbated organic matter of arctic soils

    Science.gov (United States)

    Schnecker, J.; Wild, B.; Rusalimova, O.; Mikutta, R.; Guggenberger, G.; Richter, A.

    2012-12-01

    An estimated 581 Gt organic carbon is stored in arctic soils that are affected by cryoturbtion, more than in today's atmosphere (450 Gt). The high amount of organic carbon is, amongst other factors, due to topsoil organic matter (OM) that has been subducted by freeze-thaw processes. This cryoturbated OM is usually hundreds to thousands of years old, while the chemical composition remains largely unaltered. It has therefore been suggested, that the retarded decomposition rates cannot be explained by unfavourable abiotic conditions in deeper soil layers alone. Since decomposition of soil organic material is dependent on extracellular enzymes, we measured potential and actual extracellular enzyme activities in organic topsoil, mineral subsoil and cryoturbated material from three different tundra sites, in Zackenberg (Greenland) and Cherskii (North-East Siberia). In addition we analysed the microbial community structure by PLFAs. Hydrolytic enzyme activities, calculated on a per gram dry mass basis, were higher in organic topsoil horizons than in cryoturbated horizons, which in turn were higher than in mineral horizons. When calculated on per gram carbon basis, the activity of the carbon acquiring enzyme exoglucanase was not significantly different between cryoturbated and topsoil organic horizons in any of the three sites. Oxidative enzymes, i.e. phenoloxidase and peroxidase, responsible for degradation of complex organic substances, showed higher activities in topsoil organic and cryoturbated horizons than in mineral horizons, when calculated per gram dry mass. Specific activities (per g C) however were highest in mineral horizons. We also measured actual cellulase activities (by inhibiting microbial uptake of products and without substrate addition): calculated per g C, the activities were up to ten times as high in organic topsoil compared to cryoturbated and mineral horizons, the latter not being significantly different. The total amount of PLFAs, as a proxy for

  19. Spectroscopic characterization of dissolved organic matter isolated from rainwater.

    Science.gov (United States)

    Santos, Patrícia S M; Otero, Marta; Duarte, Regina M B O; Duarte, Armando C

    2009-02-01

    Rainwater is a matrix containing extremely low concentrations (in the range of muM C) of dissolved organic carbon (DOC) and for its characterization, an efficient extraction procedure is essential. A recently developed procedure based on adsorption onto XAD-8 and XAD-4 resins in series was used in this work for the extraction and isolation of rainwater dissolved organic matter (DOM). Prior to the isolation and fractionation of DOM, and to obtain sufficient mass for the spectroscopic analyses, individual rainwater samples were batched together according to similar meteorological conditions on a total of three composed samples. The results of the isolation procedure indicated that the resin tandem procedure is not applicable for rainwater DOM since the XAD-4 resin caused samples contamination. On the other hand, the XAD-8 resin allowed DOM recoveries of 39.9-50.5% of the DOC of the original combined samples. This recovered organic fraction was characterized by UV-visible, molecular fluorescence, FTIR-ATR and 1H NMR spectroscopies. The chemical characterization of the rainwater DOM showed that the three samples consist mostly of hydroxylated and carboxylic acids with a predominantly aliphatic character, containing a minor component of aromatic structures. The obtained results suggest that the DOM in rainwater, and consequently in the precursor atmospheric particles, may have a secondary origin via the oxidation of volatile organic compounds from different origins.

  20. Plasmonics in buried structures

    OpenAIRE

    Romero, I. T.; García de Abajo, Francisco Javier

    2009-01-01

    We describe plasmon propagation in silica-filled coupled nanovoids fully buried in gold. Propagation bands and band gaps are shown to be tunable through the degree of overlap and plasmon hybridization between contiguous voids. The effect of disorder and fabrication imperfections is thoroughly investigated. Our work explores a novel paradigm for plasmon photonics relying on plasmon modes in metal-buried structures, which can benefit from long propagation distances, cancelation of radiative los...

  1. Temperature and oxygen dependence of the remineralization of organic matter

    Science.gov (United States)

    Laufkötter, C.; John, Jasmin G.; Stock, Charles A.; Dunne, John P.

    2017-07-01

    Accurate representation of the remineralization of sinking organic matter is crucial for reliable projections of the marine carbon cycle. Both water temperature and oxygen concentration are thought to influence remineralization rates, but limited data constraints have caused disagreement concerning the degree of these influences. We analyze a compilation of particulate organic carbon (POC) flux measurements from 19 globally distributed sites. Our results indicate that the attenuation of the flux of particulate organic matter depends on temperature with a Q10 between 1.5 and 2.01, and on oxygen described by a half-saturation constant between 4 and 12 μmol/L. We assess the impact of the temperature and oxygen dependence in the biogeochemistry model Carbon, Ocean Biogeochemistry, and Lower Trophics, coupled to Geophysical Fluid Dynamics Laboratory's Earth System Model ESM2M. The new remineralization parameterization results in shallower remineralization in the low latitudes but deeper remineralization in the high latitudes, redistributing POC flux toward the poles. It also decreases the volume of the oxygen minimum zones, partly addressing a long-standing bias in global climate models. Extrapolating temperature-dependent remineralization rates to the surface (i.e., beyond the depth range of POC flux data) resulted in rapid recycling and excessive surface nutrients. Surface nutrients could be ameliorated by reducing near-surface rates in a manner consistent with bacterial colonization, suggesting the need for improved remineralization constraints within the euphotic zone. The temperature and oxygen dependence cause an additional 10% decrease in global POC flux at 500 m depth, but no significant change in global POC flux at 2000 m under the RCP8.5 future projection.

  2. Photochemical Reactivity of Dissolved Organic Matter in Boreal Lakes

    Science.gov (United States)

    Gu, Y.; Vuorio, K.; Tiirola, M.; Perämäki, S.; Vahatalo, A.

    2016-12-01

    Boreal lakes are rich in dissolved organic matter (DOM) that terrestrially derived from forest soil and wetland, yet little is known about potential for photochemical transformation of aquatic DOM in boreal lakes. Transformation of chromophoric dissolved organic matter (CDOM) can decrease water color and enhance microbial mineralization, affecting primary production and respiration, which both affect the CO2 balance of the lakes. We used laboratory solar radiation exposure experiments with lake water samples collected from 54 lakes located in Finland and Sweden, representing different catchment composition and watershed location to assess photochemical reactivity of DOM. The pH of water samples ranged from 5.4 to 8.3, and the concentrations of dissolved iron (Fe) were between sunlight, and photomineralization of dissolved organic carbon (DOC) to dissolved inorganic carbon (DIC) was measured for determination of spectral apparent quantum yields (AQY). During irradiation, photobleaching decreased the absorption coefficients of CDOM at 330 nm between 4.9 and 79 m-1 by 0.5 to 11 m-1. Irradiation generated DIC from 2.8 to 79 μmol C L-1. The AQY at 330 nm ranged between 31 and 273 ×10-6 mol C mol photons-1 h-1, which was correlated positively with concentration of dissolved Fe, and negatively with pH. Further statistical analyze indicated that the interaction between pH and Fe may explain much of the photochemical reactivity of DOM in the examined lakes, and land cover concerns main catchment areas also can have impact on the photoreaction process. This study may suggest how environmental conditions regulate DOM photomineralization in boreal lakes.

  3. BiOMAS: Biochip for Organic Matter Analysis in Space

    Science.gov (United States)

    Dobrijevic, Michel; Incerti, Sebastien; Baque, Mickael; Le Postollec, Aurelie; Coussot, Gaelle; Moretto, Philippe; Vandenabeele Trambouze, Odile

    The search for the first steps of a prebiotic chemistry and the detection of life in the Solar System are ones of the great challenges of new upcoming space missions. In particular, some instruments will be designed to detect traces of organic matter on extra-terrestrial objects like Mars, Titan, comets, etc. A new and promising technique based on biochips is recommended by space agencies (ESA and NASA). A biochip is a miniaturized device composed of biological sensitive systems grafted on a slide. It allows the quantification of numerous target molecules simultaneously (from hundreds to thousands). With the support of the French space agency (CNES), our team currently develops a biochip especially designed for planetary exploration. The BiOMAS (Biochip for Organic Matter Analysis in Space) project, in progress for four years, has an interdisciplinary dimension bringing together specialists evolving in different area (planetology, physics, chemistry, biology and materials science) and developing complementary competences. A space biochip should be highly sensitive, specific and robust, allowing the detection of traces of various organic molecules (individuals and families). Since the conception of the biochip is at the heart of the instrumental specification, our aim is to optimize all the components (including the slide material, the ligands, the chemical bonds and the detection system) in order to meet both analytical and space constraints. Two different types of ligands (antibodies and aptamers) are under study to reach this objective. In space conditions, a lot of constraints might alter the efficiency of this analytical tool (irradiation by cosmic rays, temperature variations, vacuum, long duration mission, etc). Therefore, designing such a biochip requires testing the resistance of all its components to space conditions. Main concepts and current developments of the project are presented.

  4. Organic matter loss from cultivated peat soils in Sweden

    Science.gov (United States)

    Berglund, Örjan; Berglund, Kerstin

    2015-04-01

    The degradation of drained peat soils in agricultural use is an underestimated source of loss of organic matter. Oxidation (biological degradation) of agricultural peat soils causes a loss of organic matter (OM) of 11 - 22 t ha-1 y-1 causing a CO2 emission of 20 - 40 t ha-1 y-1. Together with the associated N2O emissions from mineralized N this totals in the EU to about 98.5 Mton CO2 eq per year. Peat soils are very prone to climate change and it is expected that at the end of this century these values are doubled. The degradation products pollute surface waters. Wind erosion of peat soils in arable agriculture can cause losses of 3 - 30 t ha-1 y-1 peat also causing air pollution (fine organic particles). Subsidence rates are 1 - 2 cm per year which leads to deteriorating drainage effect and make peat soils below sea or inland water levels prone to flooding. Flooding agricultural peat soils is in many cases not possible without high costs, high GHG emissions and severe water pollution. Moreover sometimes cultural and historic landscapes are lost and meadow birds areas are lost. In areas where the possibility to regulate the water table is limited the mitigation options are either to increase biomass production that can be used as bioenergy to substitute some fossil fuel, try to slow down the break-down of the peat by different amendments that inhibit microbial activity, or permanent flooding. The negative effects of wind erosion can be mitigated by reducing wind speed or different ways to protect the soil by crops or fiber sheets. In a newly started project in Sweden a typical peat soil with and without amendment of foundry sand is cropped with reed canary grass, tall fescue and timothy to investigate the yield and greenhouse gas emissions from the different crops and how the sand effect the trafficability and GHG emissions.

  5. Seasonal and spatial distribution of particulate organic matter in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, L.; Bhosle, N.B.; Matondkar, S.G.P.; Bhushan, R.

    The temporal, spatial and depth related variation of suspended particulate organic matter (POM) in the Bay of Bengal are assessed in this paper. For this purpose, suspended particulate matter (SPM) samples were collected from eight depths (2 to 1000...

  6. Distribution, origin and transformation of amino sugars sand bacterial contribution to estuarine particulate organic matter

    Digital Repository Service at National Institute of Oceanography (India)

    Khodse, V.B.; Bhosle, N.B.

    Amino sugars including bacterial biomarker muramic acid(Mur) were investigated in suspended particulate matter(SPM) to understand their distribution, origin, and biogeochemical cycling and the contribution of bacteria to particulate organic matter...

  7. [Retrieval of forest topsoil organic matter's spatial pattern based on LiDAR data].

    Science.gov (United States)

    Li, Chao; Liu, Zhao-Gang; Yue, Shu-Feng; Li, Feng-Ri; Dong, Ling-Bo; Bi, Meng

    2012-09-01

    Forest soil is one of the main carbon pools in terrestrial ecosystem. Its organic matter content can provide basic information for estimating soil carbon storage, and also, is an important index for evaluating the function of soil carbon sink. Based on the LiDAR data and the topsoil organic matter contents in 55 permanent plots at Liangshui National Nature Reserve, Heilongjiang Province of Northeast China in August 2009, and by using partial least squares (PLS) method, this paper retrieved the forest topsoil organic matter's spatial pattern in the Reserve, extracted and screened the variables related to the distribution of the topsoil organic matter (e. g. , intensity, counts, elevation, slope, and aspect), and analyzed and defined the correlations between the screened variables and topsoil organic matter content, with the prediction model of forest soil organic matter content established and validated. In the Reserve, the forest topsoil organic matter content was significantly and positively correlated with three variables (intensity, r = 0.765; counts, r = 0.423; and elevation r = 0.475; all Pforest edge and of low canopy stands, the topsoil organic matter content was less than 100 g x kg(-1). The majority of the study area had a topsoil organic matter content of 100-150 g x kg(-1), while a few areas had the topsoil organic matter content as high as 150-318.4 g x kg(-1).

  8. SNC Meteorites, Organic Matter and a New Look at Viking

    Science.gov (United States)

    Warmflash, David M.; Clemett, Simon J.; McKay, David S.

    2001-01-01

    Recently, evidence has begun to grow supporting the possibility that the Viking GC-MS would not have detected certain carboxylate salts that could have been present as metastable oxidation products of high molecular weight organic species. Additionally, despite the instrument's high sensitivity, the possibility had remained that very low levels of organic matter, below the instrument's detection limit, could have been present. In fact, a recent study indicates that the degradation products of several million microorganisms per gram of soil on Mars would not have been detected by the Viking GC-MS. Since the strength of the GC-MS findings was considered enough to dismiss the biology packet, particularly the LR results, any subsequent evidence suggesting that organic molecules may in fact be present on the Martian surface necessitates a re-evaluation of the Viking LR data. In addition to an advanced mass spectrometer to look for isotopic signatures of biogenic processes, future lander missions will include the ability to detect methane produced by methanogenic bacteria, as well as techniques based on biotechnology. Meanwhile, the identification of Mars samples already present on Earth in the form of the SNC meteorites has provided us with the ability to study samples of the Martian upper crust a decade or more in advance of any planned sample return missions. While contamination issues are of serious concern, the presence of indigenous organic matter in the form of polycyclic aromatic hydrocarbons has been detected in the Martian meteorites ALH84001 and Nakhla, while there is circumstantial evidence for carbonaceous material in Chassigny. The radiochronological ages of these meteorites are 4.5 Ga, 1.3 Ga, and 165 Ma respectively representing a span of time in Earth history from the earliest single-celled organisms to the present day. Given this perspective on organic material, a biological interpretation to the Viking LR results can no longer be ruled out. In the LR

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

    Science.gov (United States)

    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. Significance of Isotopically Labile Organic Hydrogen in Thermal Maturation of Organic Matter

    Energy Technology Data Exchange (ETDEWEB)

    Arndt Schimmelmann; Maria Mastalerz

    2010-03-30

    Isotopically labile organic hydrogen in fossil fuels occupies chemical positions that participate in isotopic exchange and in chemical reactions during thermal maturation from kerogen to bitumen, oil and gas. Carbon-bound organic hydrogen is isotopically far less exchangeable than hydrogen bound to nitrogen, oxygen, or sulfur. We explore why organic hydrogen isotope ratios express a relationship with organic nitrogen isotope ratios in kerogen at low to moderate maturity. We develop and apply new techniques to utilize organic D/H ratios in organic matter fractions and on a molecular level as tools for exploration for fossil fuels and for paleoenvironmental research. The scope of our samples includes naturally and artificially matured substrates, such as coal, shale, oil and gas.

  11. Analysis of organic matter at the soil-water interface by NMR spectroscopy: Implications for contaminant sorption processes

    Science.gov (United States)

    Simpson, M.; Simpson, A.

    2009-05-01

    Contaminant sorption to soil organic matter (OM) is the main fate of nonionic, hydrophobic organic contaminants in terrestrial environments and a number of studies have suggested that both soil OM structure and physical conformation (as regulated by the clay mineral phase) govern contaminant sorption processes. To investigate this further, a number of soil samples were characterized by both solid-state 13 C Cross Polarization Magic Angle Spinning (CPMAS) NMR and 1H High Resolution Magic Angle Spinning (HR- MAS) NMR. HR-MAS NMR is an innovative NMR method that allows one to examine samples that are semi- solid using liquid state NMR methods (ie: observe 1H which is more sensitive than 13C). With HR-MAS NMR, only those structures that are in contact with the solvent are NMR visible thus one can probe different components within a mixture using different solvents. The 1H HR-MAS NMR spectrum of a grassland soil swollen in water (D2O) is dominated by signals from alkyl and O-alkyl structures but signals from aromatic protons are negligible (the peak at ~8.2ppm is attributed to formic acid). When the soil is swollen in DMSO-d6, a solvent which is more penetrating and capable of breaking hydrogen bonds, aromatic signals are visible suggesting that the aromatic structures are buried within the soil matrix and do not exist at the soil-water interface. The 13C solid-state NMR data confirms that aromatic carbon is present in substantial amounts (estimated at ~40% of the total 13C signal) therefore, the lack of 1H aromatic signals in the HR-MAS NMR spectrum indicates that aromatic structures are buried and that the soil-water interface is dominated by aliphatic chains, carbohydrates, and peptides. The NMR data indicates that the mineral component of soils governs the physical conformation of OM at the soil-water interface.

  12. Storage and turnover of organic matter in soil

    Energy Technology Data Exchange (ETDEWEB)

    Torn, M.S.; Swanston, C.W.; Castanha, C.; Trumbore, S.E.

    2008-07-15

    Historically, attention on soil organic matter (SOM) has focused on the central role that it plays in ecosystem fertility and soil properties, but in the past two decades the role of soil organic carbon in moderating atmospheric CO{sub 2} concentrations has emerged as a critical research area. This chapter will focus on the storage and turnover of natural organic matter in soil (SOM), in the context of the global carbon cycle. Organic matter in soils is the largest carbon reservoir in rapid exchange with atmospheric CO{sub 2}, and is thus important as a potential source and sink of greenhouse gases over time scales of human concern (Fischlin and Gyalistras 1997). SOM is also an important human resource under active management in agricultural and range lands worldwide. Questions driving present research on the soil C cycle include: Are soils now acting as a net source or sink of carbon to the atmosphere? What role will soils play as a natural modulator or amplifier of climatic warming? How is C stabilized and sequestered, and what are effective management techniques to foster these processes? Answering these questions will require a mechanistic understanding of how and where C is stored in soils. The quantity and composition of organic matter in soil reflect the long-term balance between plant carbon inputs and microbial decomposition, as well as other loss processes such as fire, erosion, and leaching. The processes driving soil carbon storage and turnover are complex and involve influences at molecular to global scales. Moreover, the relative importance of these processes varies according to the temporal and spatial scales being considered; a process that is important at the regional scale may not be critical at the pedon scale. At the regional scale, SOM cycling is influenced by factors such as climate and parent material, which affect plant productivity and soil development. More locally, factors such as plant tissue quality and soil mineralogy affect

  13. Organic matter and metamorphic history of CO chondrites

    Science.gov (United States)

    Bonal, Lydie; Bourot-Denise, Michèle; Quirico, Eric; Montagnac, Gilles; Lewin, Eric

    2007-03-01

    The metamorphic grades of a series of eight CO3 chondrites (ALHA77307, Colony, Kainsaz, Felix, Lancé, Ornans, Warrenton and Isna) have been quantified. The method used was based on the structural grade of the organic matter trapped in the matrix, which is irreversibly transformed by thermal metamorphism. The maturation of the organic matter is independent with respect to the mineralogical context and aqueous alteration. This metamorphic tracer is thus valid whatever the chemical class of chondrites. Moreover, it is sensitive to the peak metamorphic temperature. The structural grade of the organic matter was used along with other metamorphic tracers such as petrography of opaque minerals, Fa and Fs silicate composition in type I chondrules, presolar grains and noble gas (P3 component) abundance. The deduced metamorphic hierarchy and the attributed petrographic types are the following: ALHA77307 (3.03) Chopin C., and Rouzaud J. N. (2002) Raman spectrum of carbonaceous material in metasediments: a new geothermometer. J. Metamorph. Geol., 20, 859-871]. A value of 330 °C was obtained for Allende (CV chondrite), Warrenton and Isna, consistent with temperatures estimated from Fe diffusion [Weinbruch S., Armstrong J., and Palme H. (1994). Constraints on the thermal history of the Allende parent body as derive from olivine-spinel thermometry and Fe/Mg interdiffusion in olivine. Geochim. Cosmochim. Acta58(2), 1019-1030.], from the Ni content in sulfide-metal assemblages [Zanda B., Bourot-Denise M., and Hewins R. (1995) Condensate sulfide and its metamorphic transformations in primitive chondrites. Meteorit. Planet. Sci.30, A605.] and from the d002 interlayer spacing in poorly graphitized carbon [Rietmeijer, F., and MacKinnon, I. (1985) Poorly graphitized carbon as a new cosmothermometer for primitive extraterrestrial materials. Nature, 315, 733-736]. The trapped noble gas and C content appear to be sensitive but not precise metamorphic tracers, indicating that the "Ornans

  14. Root Mediation of Soil Organic Matter Feedbacks to Climate Change

    Science.gov (United States)

    Pendall, E.; Carrillo, Y.; Nie, M.; Osanai, Y.; Nelson, L. C.; Sanderman, J.; Baldock, J.; Hovenden, M.

    2014-12-01

    The importance of plant roots in carbon cycling and especially soil organic matter (SOM) formation and decomposition has been recently recognized. Up to eighty percent of net primary production may be allocated to roots in ecosystems such as grasslands, where they contribute substantially to SOM formation. On the other hand, root induced priming of SOM decomposition has been implicated in the loss of soil C stocks. Thus, the accurate prediction of climate change impacts on C sequestration in soils largely depends upon improved understanding of root-mediated SOM formation and loss in the rhizosphere. This presentation represents an initial attempt to synthesize belowground observations from free-air CO2 enrichment and warming experiments in two grassland ecosystems. We found that the chemical composition of root carbon is similar to particulate organic matter (POM), but not to mineral associated organic matter (MOM), suggesting less microbial modification during formation of POM than MOM. While root biomass and production rates increased under elevated CO2, POM and MOM fractions did not increase proportionally. We also observed increased root decomposition with elevated CO2, which was likely due to increased soil water and substrate availability, since root C quality (determined by NMR) and decomposition (in laboratory incubations) were unaltered. Further, C quality and decomposition rates of roots differed between C3 and C4 functional types. Changes in root morphology with elevated CO2 have altered root functioning. Increased root surface area and length per unit mass allow increased exploration for nutrients, and potentially enhanced root exudation, rhizodeposition, and priming of SOM decomposition. Controlled chamber experiments demonstrated that uptake of N from SOM was linearly correlated with specific root length. Taken together, these results indicate that root morphology, chemistry and function all play roles in affecting soil C storage and loss, and that

  15. cyclostratigraphy, sequence stratigraphy and organic matter accumulation mechanism

    Science.gov (United States)

    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

  16. Pacific carbon cycling constrained by organic matter size, age and composition relationships

    Science.gov (United States)

    Walker, Brett D.; Beaupré, Steven R.; Guilderson, Thomas P.; McCarthy, Matthew D.; Druffel, Ellen R. M.

    2016-12-01

    Marine organic matter is one of Earth’s largest actively cycling reservoirs of organic carbon and nitrogen. The processes controlling organic matter production and removal are important for carbon and nitrogen biogeochemical cycles, which regulate climate. However, the many possible cycling mechanisms have hindered our ability to quantify marine organic matter transformation, degradation and turnover rates. Here we analyse existing and new measurements of the carbon:nitrogen ratio and radiocarbon age of organic matter spanning sizes from large particulate organic matter to small dissolved organic molecules. We find that organic matter size is negatively correlated with radiocarbon age and carbon:nitrogen ratios in coastal, surface and deep waters of the Pacific Ocean. Our measurements suggest that organic matter is increasingly chemically degraded as it decreases in size, and that small particles and molecules persist in the ocean longer than their larger counterparts. Based on these correlations, we estimate the production rates of small, biologically recalcitrant dissolved organic matter molecules at 0.11-0.14 Gt of carbon and about 0.005 Gt of nitrogen per year in the deep ocean. Our results suggest that the preferential remineralization of large over small particles and molecules is a key process governing organic matter cycling and deep ocean carbon storage.

  17. Organic Matter in Extraterrestrial Water-Bearing Salt Crystals

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.; Kebukwa, Y.; Fries, M.; Steele, A.

    2017-01-01

    Introduction: Direct samples of early Solar System fluids are present in two thermally-metamorphosed ordinary chondrite regolith breccias (Monahans (1998) [H5] and Zag [H3-6]), which were found to contain brine-bearing halite (NaCl) crystals that have been added to the regolith of an S-type asteroid following asteroidal metamorphism [1, 2]. The brine-bearing halite grains were proposed to be formed on an icy C-type asteroids (possibly Ceres), and transferred to an S-type asteroid via cryovolcanic event(s) [3]. A unique aspect of these halites is that they contain abundant organic rich solid inclusions hosted within the halites alongside the water inclusions. Methods: We analyzed in detail the compositions of the organic solids and the amino acid content of the halite crystals with two-step laser desorption/laser ionization mass spectrometry (L(sup 2) MS), Raman spectroscopy, X-ray absorption near edge structure (XANES), nanoscale secondary ion mass spectrometry (NanoSIMS), and ultra-performance liquid chromatography fluorescence detection and quadrupole time of flight hybrid mass spectrometry (UPLC-FD/QToF-MS). Results and Discussion: The L(sup 2) MS results show signatures of low-mass polyaromatic hydro-carbons (PAHs) indicated by sequences of peaks separated by 14 atomic mass units (amu) due to successive addition of methylene (CH2) groups to the PAH skeletons [4]. Raman spectra of the micron-sized solid inclusions of the halites indicate the presence of abundant and highly variable organic matter that include a mixture of short-chain aliphatic compounds and macromolecular carbon. C-XANES analysis identified C-rich areas with peaks at 285.0 eV (aromatic C=C) and 286.6 eV (vinyl-keto C=O). However, there is no 1s-sigma* exciton peak (291.7 eV) that is indicative of the development of graphene structure [5], which suggests the organics were synthesized cold. Na-noSIMS analyses show C-rich and N-rich areas that exhibit similar isotopic values with that of the IOM in

  18. Transformation of organic matters in animal wastes during composting

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke, E-mail: hitwk@sina.com [School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resource and Environment (SKLUWER), Harbin Institute of Technology, 73 Huanghe road, Harbin, Heilongjiang 150090 (China); He, Chao [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141 (Singapore); You, Shijie, E-mail: sjyou@hit.edu.cn [School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resource and Environment (SKLUWER), Harbin Institute of Technology, 73 Huanghe road, Harbin, Heilongjiang 150090 (China); Liu, Weijie [School of Life Science, The Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Province, Jiangsu Normal University, Xuzhou 221116, Jiangsu Province (China); Wang, Wei; Zhang, Ruijun [School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resource and Environment (SKLUWER), Harbin Institute of Technology, 73 Huanghe road, Harbin, Heilongjiang 150090 (China); Qi, Huanhuan; Ren, Nanqi [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141 (Singapore)

    2015-12-30

    Highlights: • Transformation of swine, cow and chicken manures during composting was compared. • Evolution of organics was analyzed by element analysis, FTIR, {sup 13}C NMR and Py/GC/MS. • Microbial utilization capacity on various substrates in the manures was evaluated. • Spatial difference of degradation rate inside the manure particle was investigated. - Abstract: The transformation of organic matters in swine, cow and chicken manures was compared and evaluated using elemental analysis, FTIR, {sup 13}C NMR, pyrolysis/GC/MS, Biolog and multiple fluorochrome over 60 days composting. The results revealed that cow manure exhibited the greatest C/N and aromaticity, whereas chicken manure exhibited the highest nitrogen and sulfur contents. O-alkyl-C was predominant carbon structure in the three manures. Alkyl-C and carboxyl-C were decomposed dramatically in initial 10 days, and mineralization of O-alkyl-C dominated the curing stage. During pyrolysis of chicken, cow, and swine manures, the majority products were fatty acids, phenols and cholestene derivatives, respectively, however, phenols and cholestene derivatives were strongly reduced in the mature manures. Furthermore, microorganisms in the raw cow, chicken and swine manure demonstrated the highest degradation capabilities for carbohydrates, lipids and amino acids, respectively. Spatial differences in the contents of solid organics in the manure particles were negligible through detection by multiple staining methods during composting.

  19. Acid-base properties of Baltic Sea dissolved organic matter

    Science.gov (United States)

    Hammer, Karoline; Schneider, Bernd; Kuliński, Karol; Schulz-Bull, Detlef E.

    2017-09-01

    Calculations related to the marine CO2 system that are based on alkalinity data may be strongly biased if the contributions of organic compounds are ignored. In coastal seas, concentrations of dissolved organic matter (DOM) are frequently high and alkalinity from inorganic compounds is low. In this study, based on measurements of total alkalinity, total CO2, and pH, we determined the organic alkalinity, Aorg, in water from the central Baltic Sea. The maximum Aorg measured in the surface mixed layer during the spring bloom was > 50 μmol/kg-SW but the Aorg decreased with depth and approached zero below the permanent halocline. This behavior could be attributed to the decreased pH of deeper water layers. The data were used to calculate the bulk dissociation constant, KDOM, for marine DOM and the fraction f of dissolved organic carbon (DOC) that acts as a carrier for acid-base functional groups. The p KDOM (7.27) agreed well with the value (7.34) previously estimated in a preliminary study of organic alkalinity in the Baltic Sea. The fraction of carbon atoms carrying acid-base groups was 17% and was somewhat higher than previously reported (12%). Spike experiments performed using artificial seawater and three different humic/fulvic substances tested whether the acid-base properties of these substances explain the results of our field study. Specifically, Aorg was determined at different concentrations (DOC) of the added humic/fulvic substances. The relationship between Aorg and the DOC concentrations indicated that humic/fulvic substances are more acidic (p KDOM < 6.5) than the bulk DOC natural occurring in the Baltic Sea.

  20. New monoaromatic steroids in organic matter of the apocatagenesis zone

    Science.gov (United States)

    Kashirtsev, V. A.; Fomin, A. N.; Shevchenko, N. P.; Dolzhenko, K. V.

    2016-08-01

    According to the materials of geochemical study in the core of the ultradeep hole SV-27 of aromatic fractions of bitumoids of the Vilyui syneclise (East Siberia) by the method of chromatography-mass spectrometry, starting from the depth of >5000 m, four diastereomers of previously unknown hydrocarbons, which become predominant in the fraction at a depth of ˜6500 m, were distinguished. Similar hydrocarbons were found in organic matter of Upper Paleozoic rocks of the Kharaulakh anticlinorium in the Verkhoyansk folded area. According to the intense molecular ion m/z 366 and the character of the basic fragmental ions (m/z 238, 309, and 323), the major structure of the compounds studied was determined as 17-desmethyl-23-methylmonoaromatic steroid C27. The absence of such steroids in oil of the Vilyui syneclise shows that deep micro-oils did not participate in the formation of oil fringes of gas condensate deposits of the region.

  1. Editorial: Integrative Research on Organic Matter Cycling across Aquatic Gradients

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Nicholas D.

    2017-05-04

    The interface between freshwater and marine ecosystems provides a unique setting to examine the evolution of biogeochemical components derived from the landscape, inland waters, estuaries, and the ocean across distinct physiochemical gradients. A diverse body of work exploring this research topic is highlighted here with the goal of integrating our understanding of how organic matter (OM) is transported and transformed along the terrestrial-aquatic continuum and sparking interdisciplinary discussions on future research needs. The movement of water ultimately controls the transport and transformation of geochemical components as they move from land to sea, and, as such, contributions to this research topic will be described within the context of the hydrological cycle, starting with rainfall.

  2. Development of Alternative Methods for Determining Soil Organic Matter

    Directory of Open Access Journals (Sweden)

    Diego Mendes de Souza

    2016-01-01

    Full Text Available ABSTRACT Soil organic matter (SOM is important to fertility, since it performs several functions such as cycling, water and nutrient retention and soil aggregation, in addition to being an energy requirement for biological activity. This study proposes new trends to the Embrapa, Walkley-Black, and Mebius methods that allowed the determination of SOM by spectrophotometry, increasing functionality. The mass of 500 mg was reduced to 200 mg, generating a mean of 60 % saving of reagents and a decrease of 91 % in the volume of residue generated for the three methods without compromising accuracy and precision. We were able to optimize conditions for the Mebius method and establish the digestion time of maximum recovery of SOM by factorial design and response surface. The methods were validated by the estimate of figures of merits. Between the methods investigated, the optimized Mebius method was best suited for determining SOM, showing near 100 % recovery.

  3. Systematic approaches to comprehensive analyses of natural organic matter

    Science.gov (United States)

    Leenheer, Jerry A.

    2009-01-01

    The more that is learned of the chemistry of aquatic natural organic matter (NOM) the greater is the scientific appreciation of the vast complexity of this subject. This complexity is due not only to a multiplicity of precursor molecules in any environment but to their associations with each other and with other components of local environments such as clays, mineral acids and dissolved metals. In addition, this complex system is subject to constant change owing to environmental variables and microbial action. Thus, there is a good argument that no two NOM samples are exactly the same even from the same source at nearly the same time. When ubiquity of occurrence, reaction with water treatment chemicals, and subsequent human exposure are added to the list of NOM issues, one can understand the appeal that this subject holds for a wide variety of environmental scientists.

  4. Nanoscale Structure Of Organic Matter Explain Its Recalcitrance To Degradation

    Science.gov (United States)

    Spagnol, M.; Salati, S.; Papa, G.; Tambone, F.; Adani, F.

    2009-04-01

    Recalcitrance can be defined as the natural resistance of organic matter (OM) to microbial and enzymatic deconstruction (Himmel et al., 2007). The nature of OM recalcitrance remained not completely understood and more studies need above all to elucidate the role of the chemical topography of the OM at nanometer scale. Hydrolytic enzymes responsible of OM degradation have a molecular weight of 20-25 kD, corresponding to a size of about 4 nm, hardly penetrate into micropores (i.e. the pore having a diameter Foust, T.D. Sci. 2007, 315, 804-807. Chesson, A. In Driven by nature Plant Litter Quality and Decomposition. Cadisch, G.; Giller, K.E. Eds.; CAB International: Wallinford, UK 1997, pp 47-66. Zimmerman, A.R.; Goyne, K.W.; Chorover, J, Komarneni, S.; Brantley, S.L. Org Geochem. 2004, 35, 355-375.

  5. Ocean warming-acidification synergism undermines dissolved organic matter assembly.

    Science.gov (United States)

    Chen, Chi-Shuo; Anaya, Jesse M; Chen, Eric Y-T; Farr, Erik; Chin, Wei-Chun

    2015-01-01

    Understanding the influence of synergisms on natural processes is a critical step toward determining the full-extent of anthropogenic stressors. As carbon emissions continue unabated, two major stressors--warming and acidification--threaten marine systems on several scales. Here, we report that a moderate temperature increase (from 30°C to 32°C) is sufficient to slow--even hinder--the ability of dissolved organic matter, a major carbon pool, to self-assemble to form marine microgels, which contribute to the particulate organic matter pool. Moreover, acidification lowers the temperature threshold at which we observe our results. These findings carry implications for the marine carbon cycle, as self-assembled marine microgels generate an estimated global seawater budget of ~1016 g C. We used laser scattering spectroscopy to test the influence of temperature and pH on spontaneous marine gel assembly. The results of independent experiments revealed that at a particular point, both pH and temperature block microgel formation (32°C, pH 8.2), and disperse existing gels (35°C). We then tested the hypothesis that temperature and pH have a synergistic influence on marine gel dispersion. We found that the dispersion temperature decreases concurrently with pH: from 32°C at pH 8.2, to 28°C at pH 7.5. If our laboratory observations can be extrapolated to complex marine environments, our results suggest that a warming-acidification synergism can decrease carbon and nutrient fluxes, disturbing marine trophic and trace element cycles, at rates faster than projected.

  6. Scaling soil organic matter formation with microbial physiology

    Science.gov (United States)

    Grandy, S.

    2015-12-01

    Soil organic matter (SOM) regulates multiple ecosystem processes, including the exchange of trace gases and primary productivity. Recently, there has been vigorous debate over the role that microbial products play in forming stable soil organic matter, with increasing analytical evidence using isotopes, molecular chemistry, and microcopy all showing that SOM possesses a strong microbial signature. However, scaling these observations - typically made at the molecular to nano or micron scales - to ecosystems or larger scales remains challenging. Here we show that microbial physiological processes such as growth efficiency and growth rate regulate the accumulation of microbial products. These processes are also strongly regulated by ecosystem disturbance and can be readily incorporated into microbial-explicit global C cycling models. In our experiments with model artificial soils accruing SOM and field soils with varying soil C concentrations, the accumulation of SOM is closely related to microbial physiology. Further, the rate and efficiency that isotopically labelled C is converted to soil C depends strongly on microbial physiological characteristics. Given the sensitivity of microbial physiological characteristics to disturbance, these physiological traits can help explain ecosystem-scale SOM responses to environmental changes. Variation in microbial physiology can also be directly incorporated into models, allowing us to scale microbial processes that regulate SOM formation to regional and global scales. Here we demonstrate the incorporation of microbial processes into MIMICS, the MIcrobial MIneral Carbon Stabilization model. Moving from ecosystem to larger scales, we demonstrate that MIMICS, a microbial-explicit model with output strongly dependent on microbial physiology is able to predict large-scale soil C dynamics as well as or better than conventional models. Microbial physiology, which varies among microbial groups and is highly sensitive disturbance, can

  7. Effects of warming on stream biofilm organic matter use capabilities.

    Science.gov (United States)

    Ylla, Irene; Canhoto, Cristina; Romaní, Anna M

    2014-07-01

    The understanding of ecosystem responses to changing environmental conditions is becoming increasingly relevant in the context of global warming. Microbial biofilm communities in streams play a key role in organic matter cycling which might be modulated by shifts in flowing water temperature. In this study, we performed an experiment at the Candal stream (Portugal) longitudinally divided into two reaches: a control half and an experimental half where water temperature was 3 °C above that of the basal stream water. Biofilm colonization was monitored during 42 days in the two stream halves. Changes in biofilm function (extracellular enzyme activities and carbon substrate utilization profiles) as well as chlorophyll a and prokaryote densities were analyzed. The biofilm in the experimental half showed a higher capacity to decompose cellulose, hemicellulose, lignin, and peptidic compounds. Total leucine-aminopeptidase, cellobiohydrolase and β-xylosidase showed a respective 93, 66, and 61% increase in activity over the control; much higher than would be predicted by only the direct temperature physical effect. In contrast, phosphatase and lipase activity showed the lowest sensitivity to temperature. The biofilms from the experimental half also showed a distinct functional fingerprint and higher carbon usage diversity and richness, especially due to a wider use of polymers and carbohydrates. The changes in the biofilm functional capabilities might be indirectly affected by the higher prokaryote and chlorophyll density measured in the biofilm of the experimental half. The present study provides evidence that a realistic stream temperature increase by 3 °C changes the biofilm metabolism to a greater decomposition of polymeric complex compounds and peptides but lower decomposition of lipids. This might affect stream organic matter cycling and the transfer of carbon to higher trophic levels.

  8. Biochar effect on the mineralization of soil organic matter

    Directory of Open Access Journals (Sweden)

    Sander Bruun

    2012-05-01

    Full Text Available The objective of this work was to verify whether the addition of biochar to the soil affects the degradation of litter and of soil organic matter (SOM. In order to investigate the effect of biochar on the mineralization of barley straw, soil was incubated with 14C-labelled barley straw with or without unlabelled biochar. To investigate the effect of straw on the mineralization of biochar, soil was incubated with 14C-labelled biochar with or without straw. In addition, to investigate the effect of biochar on old SOM, a soil labelled by applying labelled straw 40 years ago was incubated with different levels of biochar. All experiments had a control treatment, without any soil amendment. The effect of biochar on the straw mineralization was small and nonsignificant. Without biochar, 48±0.2% of the straw carbon was mineralized within the 451 days of the experiment. In comparison, 45±1.6% of C was mineralized after biochar addition of 1.5 g kg-1. In the SOM-labelled soil, the organic matter mineralized more slowly with the increasing doses of biochar. Biochar addition at 7.7 g kg-1 reduced SOM mineralization from 6.6 to 6.3%, during the experimental period. The addition of 15.5 g kg-1 of biochar reduced the mineralized SOM to 5.7%. There is no evidence of increased degradation of either litter or SOM due to biochar addition; consequently, there is no evidence of decreased stability of SOM.

  9. Priming-induced Changes in Permafrost Soil Organic Matter Decomposition

    Science.gov (United States)

    Pegoraro, E.; Schuur, E.; Bracho, R. G.

    2015-12-01

    Warming of tundra ecosystems due to climate change is predicted to thaw permafrost and increase plant biomass and litter input to soil. Additional input of easily decomposable carbon can alter microbial activity by providing a much needed energy source, thereby accelerating soil organic matter decomposition. This phenomenon, known as the priming effect, can increase CO2 flux from soil to the atmosphere. However, the extent to which this mechanism can decrease soil carbon stocks in the Arctic is unknown. This project assessed priming effects on permafrost soil collected from a moist acidic tundra site in Healy, Alaska. We hypothesized that priming would increase microbial activity by providing microbes with a fresh source of carbon, thereby increasing decomposition of old and slowly decomposing carbon. Soil from surface and deep layers were amended with multiple pulses of uniformly 13C labeled glucose and cellulose, and samples were incubated at 15° C to quantify whether labile substrate addition increased carbon mineralization. We quantified the proportion of old carbon mineralization by measuring 14CO2. Data shows that substrate addition resulted in higher respiration rates in amended soils; however, priming was only observed in deep layers, where 30% more soil-derived carbon was respired compared to control samples. This suggests that microbes in deep layers are limited in energy, and the addition of labile carbon increases native soil organic matter decomposition, especially in soil with greater fractions of slowly decomposing carbon. Priming in permafrost could exacerbate the effects of climate change by increasing mineralization rates of carbon accumulated over the long-term in deep layers. Therefore, quantifying priming effect in permafrost soils is imperative to understanding the dynamics of carbon turnover in a warmer world.

  10. Ocean warming-acidification synergism undermines dissolved organic matter assembly.

    Directory of Open Access Journals (Sweden)

    Chi-Shuo Chen

    Full Text Available Understanding the influence of synergisms on natural processes is a critical step toward determining the full-extent of anthropogenic stressors. As carbon emissions continue unabated, two major stressors--warming and acidification--threaten marine systems on several scales. Here, we report that a moderate temperature increase (from 30°C to 32°C is sufficient to slow--even hinder--the ability of dissolved organic matter, a major carbon pool, to self-assemble to form marine microgels, which contribute to the particulate organic matter pool. Moreover, acidification lowers the temperature threshold at which we observe our results. These findings carry implications for the marine carbon cycle, as self-assembled marine microgels generate an estimated global seawater budget of ~1016 g C. We used laser scattering spectroscopy to test the influence of temperature and pH on spontaneous marine gel assembly. The results of independent experiments revealed that at a particular point, both pH and temperature block microgel formation (32°C, pH 8.2, and disperse existing gels (35°C. We then tested the hypothesis that temperature and pH have a synergistic influence on marine gel dispersion. We found that the dispersion temperature decreases concurrently with pH: from 32°C at pH 8.2, to 28°C at pH 7.5. If our laboratory observations can be extrapolated to complex marine environments, our results suggest that a warming-acidification synergism can decrease carbon and nutrient fluxes, disturbing marine trophic and trace element cycles, at rates faster than projected.

  11. Riverine organic matter composition and fluxes to Hudson Bay

    Science.gov (United States)

    Kuzyk, Z. Z. A.; Macdonald, R. W.; Goni, M. A.; Godin, P.; Stern, G. A.

    2016-12-01

    With warming in northern regions, many changes including permafrost degradation, vegetation alteration, and wildfire incidence will impact the carbon cycle. Organic carbon (OC) carried by river runoff to northern oceans has the potential to provide integrated evidence of these impacts. Here, concentrations of dissolved (DOC) and particulate (POC) OC are used to estimate terrestrial OC transport in 17 major rivers draining varied vegetative and permafrost conditions into Hudson Bay and compositional data (lignin and 14C) to infer OC sources. Hudson Bay lies just south of the Arctic Circle in Canada and is surrounded by a large drainage basin (3.9 × 106 km2) dominated by permafrost. Analysis of POC and DOC in the 17 rivers indicates that DOC dominates the total OC load. The southern rivers dominate. The Nelson and Churchill Rivers to the southwest are particularly important suppliers of OC partly because of large drainage basins but also perhaps because of impacts by hydroelectric development, as suggested by a 14C age of DOC in the Churchill River of 2800 years. Higher DOC and POC concentrations in the southern rivers, which have substantive areas only partially covered by permafrost, compared to northern rivers draining areas with complete permafrost cover, implies that warming - and hence permafrost thawing - will lead to progressively higher DOC and POC loads for these rivers. Lignin composition in the organic matter (S/V and C/V ratios) reveals mixed sources of OC consistent with the dominant vegetation in the river basins. This vegetation is organized by latitude with southern regions below the tree line enriched by woody gymnosperm sources (boreal forest) and northern regions enriched with organic matter from non-woody angiosperms (flowering shrubs, tundra). Acid/Aldehyde composition together with Δ14C data for selected DOC samples suggest that most of the lignin has undergone oxidative degradation, particularly the DOC component. However, high Δ14C ages

  12. Refining Soil Organic Matter Determination by Loss-on-Ignition

    Institute of Scientific and Technical Information of China (English)

    M. H. SALEHI; O. HASHEMI BENI; H. BEIGI HARCHEGANI; I. ESFANDIARPOUR BORUJENI; H. R. MOTAGHIAN

    2011-01-01

    Wet oxidation procedure,i.e.,Walkley-Black (WB) method,is a routine,relatively accurate,and popular method for the determination of soil organic matter (SOM) but it is time-consuming,costly and also has a high potential to cause environmental pollution because of disposal of chromium and strong acids used in this analysis.Therefore,loss-on-ignition (LOI) procedure,a simple and cheap method for SOM estimation,which also avoids chromic acid wastes,deserves more attention.The aims of this research were to study the statistical relationships between SOM determined with the LOI (SOMLoI) and WB (SOMWB) methods to compare the spatial variability of SOM in two major plains,Shahrekord and Koohrang plains,of Chaharmahal-va-Bakhtiari Province,Iran.Fifty surface soil samples (0-25 cm) were randomly collected in each plain to determine SOM using the WB method and the LOI procedure at 300,360,400,500 and 550 ℃ for 2 h. The samples covered wide ranges of soil texture and calcium carbonate equivalent (CCE).The general linear form of the regression equation was calculated to estimate SOMLOI from SOM obtained by the WB method for both overall samples and individual plains.Forty soil samples were also randomly selected to compare the SOM and CCE before and after ignition at each temperature.Overall accuracy of the continuous maps generated for the LOI and WB methods was considered to determine the accordance of two procedures.Results showed a significant positive linear relationship between SOMLOI and SOMWB.Coefficients of determination (R2) of the equations for individual plains were higher than that of the overall equation.Coefficients of determination and line slopes decreased and root mean square error (RMSE) increased with increasing ignition temperature,which may be due to the mineral structural water loss and destruction of carbonates at higher temperatures.A temperature around 360 ℃ was identified as optimum as it burnt most organic carbon,destroyed less inorganic carbon

  13. What bacteria leave behind: bacterial organic matter quality and biomarker signals

    DEFF Research Database (Denmark)

    Piil, Kristoffer; Schramm, Andreas; Niggemann, Jutta

    WHAT BACTERIA LEAVE BEHIND: BACTERIAL ORGANIC MATTER QUALITY AND BIOMARKER SIGNALS Knowledge of the cellular content of bacterial biomarkers (D-amino acids and muramic acid) provides us with a powerful tool to trace production and fate of bacterially derived organic matter. The biochemical...... negatives and Archaea, in relation to prokaryotic contribution to sediment organic matter pools. Poster presentation Session #:053 Date: 01-29-09 Time: 18:00 - 20:00 Presentation is given by student: Yes...

  14. Second Hydrocarbon—Generation from Organic Matter Trapped in Fluid Inclusions in Carbonate Rocks

    Institute of Scientific and Technical Information of China (English)

    施继锡; 余孝颖

    1999-01-01

    The mechanism and significance of second hydrocarbon-generation from organic matter trapped in fluid inclusions in carbonate rocks are discussed.The types of organic matter and the relationship between them are also reviewed.The organic matter trapped in inclusions and crystals,which account for more than 20%of the total organic matter in carbonate rocks,may be of great significance in the generation of hydrocarbons.High-temperature oil resulting from second hydrocarbon-generation should be an important target,in addition to natural gas,in oilgas prospecting in regions of high-maturity carbonate rocks.

  15. Significance of evolution features of organic matter in studying orogenic belt

    Energy Technology Data Exchange (ETDEWEB)

    Cao, D.; Zhang, S. [China University of Mining and Technology, Beijing (China). Dept of Resource Exploitation Engineering

    2000-07-01

    The evolution features of depositional organic matters in orogenic belt may reflect a lot of geological information such as temperature, confining pressure, stress, strain, and so on. Organic matters maybe coming into use as the sensitive temperature-pressure-meter for the reconstruction of orogenic process, especially at the stage of very low-grade metamorphism. The basic evolution law of organic matter and its controlling factors were introduced. Based on this, the possible uses of analysing the evolution features of organic matter in studying orogenic belt were discussed. 37 refs., 2 figs.

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

    Science.gov (United States)

    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.

  17. Controlled experimental soil organic matter modification for study of organic pollutant interactions in soil

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Ashour A., E-mail: ashour.ahmed@uni-rostock.de [University of Rostock, Institute of Physics, 18051 Rostock (Germany); University of Cairo, Faculty of Science, Department of Chemistry, 12613 Giza (Egypt); University of Rostock, Interdisciplinary Faculty, Department of Life, Light and Matter, 18051 Rostock (Germany); Kuehn, Oliver, E-mail: oliver.kuehn@uni-rostock.de [University of Rostock, Institute of Physics, 18051 Rostock (Germany); University of Rostock, Interdisciplinary Faculty, Department of Life, Light and Matter, 18051 Rostock (Germany); Leinweber, Peter, E-mail: peter.leinweber@uni-rostock.de [University of Rostock, Soil Science, 18051 Rostock (Germany); University of Rostock, Interdisciplinary Faculty, Department of Life, Light and Matter, 18051 Rostock (Germany)

    2012-12-15

    Interactions of organic pollutants with soil organic matter can be studied by adsorption of the pollutants on well-characterized soil samples with constant mineralogy but different organic matter compositions. Therefore, the objectives of the current study are establishing a set of different, well-characterized soil samples by systematic modifications of their organic matter content and molecular composition and prove these modifications by advanced complementary analytical techniques. Modifications were done by off-line pyrolysis and removal/addition of hot-water extracted organic fraction (HWE) from/to the original soil sample. Both pyrolysis-field ionization mass spectrometry (Py-FIMS) and synchrotron-based C- and N- X-ray absorption near-edge structure spectroscopy (XANES) were applied to investigate the composition of the soil organic matter. These complementary analytical methods in addition to elemental analysis agreed in showing the following order of organic matter contents: pyrolyzed soil < soil residue < original soil < soil + 3 HWE < soil + 6 HWE < HWE. The addition of HWE to the soil sample increases the relative proportions of carbohydrates, N-containing heterocyclic compounds and peptides, and decreases the relative proportions of phenols, lignin monomers and dimers, and lipids. The most abundant organic compound classes in the pyrolyzed sample are aromatics, aliphatic nitriles, aldehydes, five- and six-membered N-containing heterocyclic compounds, and aliphatic carboxylic acids. It can be expected that removal or addition of HWE, that mimic biomass inputs to soil or soil amendments, change the binding capacity for organic pollutants less intensively than heat impact, e.g. from vegetation burning. It will be possible to interpret kinetic data on the pollutants adsorption by these original and modified soil samples on the basis of the bond- and element-specific speciation data through C-XANES and N-XANES and the molecular-level characterization

  18. Chromophoric dissolved organic matter export from U.S. rivers

    Science.gov (United States)

    Spencer, Robert G. M.; Aiken, George R.; Dornblaser, Mark M.; Butler, Kenna D.; Holmes, R. Max; Fiske, Greg; Mann, Paul J.; Stubbins, Aron

    2013-01-01

    Chromophoric dissolved organic matter (CDOM) fluxes and yields from 15 major U.S. rivers draining an assortment of terrestrial biomes are presented. A robust relationship between CDOM and dissolved organic carbon (DOC) loads is established (e.g., a350 versus DOC; r2 = 0.96, p export from ungauged watersheds. A large variation in CDOM yields was found across the rivers. The two rivers in the north-eastern U.S. (Androscoggin and Penobscot), the Edisto draining into the South Atlantic Bight, and some rivers draining into the Gulf of Mexico (Atchafalaya and Mobile) exhibit the highest CDOM yields, linked to extensive wetlands in these watersheds. If the Edisto CDOM yield is representative of other rivers draining into the South Atlantic Bight, this would result in a CDOM load equivalent to that of the Mississippi from a region of approximately 10% of the Mississippi watershed, indicating the importance of certain regions with respect to the role of terrigenous CDOM in ocean color budgets.

  19. Hydrology controls dissolved organic matter (DOM) quality and dynamics

    Science.gov (United States)

    Fasching, Christina; Schelker, Jakob; Ulseth, Amber; Singer, Gabriel; Steniczka, Gertraud; Battin, Tom

    2014-05-01

    Headwater streams are major contributors to carbon cycling. It is therefore of utmost importance to understand the dynamics of dissolved organic matter (DOM) and its drivers in these ecosystems. Here we present data from more than 4,000 individual DOM measurements from Oberer Seebach, a 3rd-order stream draining a largely pristine alpine catchment (Lunz am See, Austria). We determined the concentration of streamwater and hyporheic dissolved organic carbon and a suite of optical properties of DOM based on a diurnal sampling design over almost three years; we also monitored various hydrological and climate parameters over that same time. Optical properties were determined from absorbance measurements and parallel factor analysis (PARAFAC) modelling of Excitation emission matrices. We also estimated DOM export fluxes from Oberer Seebach and the contributions of the various chromophoric and fluorescent components to these exports. Preliminary results suggest that DOM in Oberer Seebach was largely of terrigenous origin throughout the year. However during periods of low discharge autochthonous DOM export increased, indicating freshly produced DOM possibly from benthic algae. Hyphoreic and streamwater DOM composition and its dynamics were tightly coupled in time at baseflow, yet displaying higher variability as discharge increased. Our timeseries studies highlight the relevance of the flow regime on the dynamics, origin and composition of DOM in a headwater stream. We discuss these findings in the context of extreme hydrological events on carbon fluxes.

  20. Global effects of agriculture on fluvial dissolved organic matter.

    Science.gov (United States)

    Graeber, Daniel; Boëchat, Iola G; Encina-Montoya, Francisco; Esse, Carlos; Gelbrecht, Jörg; Goyenola, Guillermo; Gücker, Björn; Heinz, Marlen; Kronvang, Brian; Meerhoff, Mariana; Nimptsch, Jorge; Pusch, Martin T; Silva, Ricky C S; von Schiller, Daniel; Zwirnmann, Elke

    2015-11-06

    Agricultural land covers approximately 40% of Earth's land surface and affects hydromorphological, biogeochemical and ecological characteristics of fluvial networks. In the northern temperate region, agriculture also strongly affects the amount and molecular composition of dissolved organic matter (DOM), which constitutes the main vector of carbon transport from soils to fluvial networks and to the sea, and is involved in a large variety of biogeochemical processes. Here, we provide first evidence about the wider occurrence of agricultural impacts on the concentration and composition of fluvial DOM across climate zones of the northern and southern hemispheres. Both extensive and intensive farming altered fluvial DOM towards a more microbial and less plant-derived composition. Moreover, intensive farming significantly increased dissolved organic nitrogen (DON) concentrations. The DOM composition change and DON concentration increase differed among climate zones and could be related to the intensity of current and historical nitrogen fertilizer use. As a result of agriculture intensification, increased DON concentrations and a more microbial-like DOM composition likely will enhance the reactivity of catchment DOM emissions, thereby fuelling the biogeochemical processing in fluvial networks, and resulting in higher ecosystem productivity and CO2 outgassing.

  1. Natural Organic Matter and the Event Horizon of Mass Spectrometry

    Science.gov (United States)

    Hertkorn, N.; Frommberger, M.; Witt, M.; Koch, B. P.; Schmitt-Kopplin, P.; Perdue, E. M.

    2009-05-01

    Soils, sediments, freshwaters and marine waters contain natural organic matter (NOM) - an exceedingly complex mixture of organic compounds that collectively exhibit a nearly continuous range of properties (size- reactivity continuum). NOM is composed mainly of carbon, hydrogen and oxygen, with minor contributions from heteroatoms such as sulphur and phosphorus. Suwannee River fulvic acid (SuwFA) is a fraction of NOM that is relatively depleted in heteroatoms. Ultrahigh resolution Fourier transform ion cyclotron (FTICR) mass spectra of SuwFA reveal several thousand molecular formulae, corresponding in turn to several hundred thousand distinct chemical environments of carbon even without accountancy of isomers. The mass difference m among adjoining C,H,O-molecules between and within clusters of nominal mass is inversely related to molecular dissimilarity: any decrease of m imposes an ever growing mandatory difference in molecular composition. Molecular formulae that are expected for likely biochemical precursor molecules are notably absent from these spectra, indicating that SuwFA is the product of diagenetic reactions that have altered the major components of biomass beyond the point of recognition. The degree of complexity of SuwFA can be brought into sharp focus through comparison with the theoretical limits of chemical complexity, as constrained and quantized by the fundamentals of chemical binding. The theoretical C,H,O-compositional space denotes the isomer-filtered complement of the entire, very vast space of molecular structures composed solely of carbon, hydrogen and oxygen. The molecular formulae within SuwFA occupy a sizable proportion of the theoretical C,H,O-compositional space. A one-hundred percent coverage of the theoretically feasible C,H,O-compositional space by SuwFA molecules is attained throughout a sizable range of mass, H/C and O/C elemental ratios. The substantial differences between (and complementarity of) the SuwFA molecular formulae that

  2. Buried Craters of Utopia

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-365, 19 May 2003Beneath the northern plains of Mars are numerous buried meteor impact craters. One of the most heavily-cratered areas, although buried, occurs in Utopia Planitia, as shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. The history of Mars is complex; impact craters provide a tool by which to understand some of that history. In this case, a very ancient, cratered surface was thinly-buried by younger material that is not cratered at all. This area is near 48.1oN, 228.2oW; less than 180 km (112 mi) west of the Viking 2 lander site. Sunlight illuminates the scene from the lower left.

  3. Organic Coatings on Primitive Grains in IDPs: Implications for the Formation of Solar System Organic Matter

    Science.gov (United States)

    Flynn, G. J.; Wirick, S.; Keller, L. P.; Sandford, S.

    2009-12-01

    Chondritic, porous interplanetary dust particles (CP IDPs) are the most primitive samples of extraterrestrial material available for laboratory analysis [1]. These ~10 micron CP IDPs are unequilibrated aggregates of mostly submicron, anhy-drous grains of a diverse variety, including olivine, pyroxene, glass, and sulfide. We previously reported that CP IDPs contain a significant amount of organic matter, and concluded that parent body aqueous processing, which these IDPs never experienced, was not the mechanism that produced much of the pre-biotic organic matter of the early Solar System [2]. However, we were not able to establish either the time or mechanism of its production. The individual grains in these CP IDPs are coated by layers of carbonaceous material [3], typically ~100 nm thick, which holds the grains together. We have analyzed these grain coatings by X-ray Absorption Near-Edge Structure (XANES) spectroscopy using the Scanning Transmission X-Ray Microscope (STXM) on beamline X1A of the National Synchrotron Light Source. We have obtained C-XANES maps, using a 35 nm probe spot, of ultramicrotome sections from CP IDPs. Cluster analysis, which compares spectra from each pixel in the map and identifies groups of pixels exhibiting similar spectra [4], was used to analyze the data. Cluster analysis indicates most carbonaceous grain coatings have very similar C-XANES spectra, demonstrating that carbonaceous coatings on the individual grains in CP IDPs are organic, with the two strongest absorption features from C=C and C=O. This organic matter coats the individual grains, implying an assembly sequence beginning with grain formation, followed by the emplacement of the organic coating, and finally the assembly of the primitive dust particles. The organic grain coatings in the primitive CP IDPs appear to have formed prior to the aggregation of the most primitive dust particles currently available for laboratory analysis, indicating that these grain coatings are the

  4. Key soil functional properties affected by soil organic matter - evidence from published literature

    Science.gov (United States)

    Murphy, Brian

    2015-07-01

    The effect of varying the amount of soil organic matter on a range of individual soil properties was investigated using a literature search of published information largely from Australia, but also included relevant information from overseas. Based on published pedotransfer functions, soil organic matter was shown to increase plant available water by 2 to 3 mm per 10 cm for each 1% increase in soil organic carbon, with the largest increases being associated with sandy soils. Aggregate stability increased with increasing soil organic carbon, with aggregate stability decreasing rapidly when soil organic carbon fell below 1.2 to 1.5 5%. Soil compactibility, friability and soil erodibility were favourably improved by increasing the levels of soil organic carbon. Nutrient cycling was a major function of soil organic matter. Substantial amounts of N, P and S become available to plants when the soil organic matter is mineralised. Soil organic matter also provides a food source for the microorganisms involved in the nutrient cycling of N, P, S and K. In soils with lower clay contents, and less active clays such as kaolinites, soil organic matter can supply a significant amount of the cation exchange capacity and buffering capacity against acidification. Soil organic matter can have a cation exchange capacity of 172 to 297 cmol(+)/kg. As the cation exchange capacity of soil organic matter varies with pH, the effectiveness of soil organic matter to contribute to cation exchange capacity below pH 5.5 is often minimal. Overall soil organic matter has the potential to affect a range of functional soil properties.

  5. The flux of organic matter through a peatland ecosystem - evidence from thermogravimetric analysis

    Science.gov (United States)

    Worrall, Fred; Moody, Catherine; Clay, Gareth

    2016-04-01

    Carbon budgets of peatlands are now common and studies have considered nitrogen, oxygen and energy budgets, but no study has considered the whole composition of the organic matter as it transfers through and into a peatland. Organic matter samples were taken from each organic matter reservoir found in and each fluvial flux from a peatland and analysed the samples by thermogravimetric analysis. The samples analysed were: aboveground, belowground, heather, mosses and sedges, litter layer, a peat core, 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, humic acid and plant protein. Results showed that the thermogravimetric trace of the sampled organic matter were distinctive with the DOM traces being marked out by very low thermal stability relative other organic matter types. The peat profile shows a significant trend with depth from vegetation- to lignin-like composition. When all traces are weighted according to the observed dry matter and carbon budgets for the catchment then it is possible to judge what has been lost in the transition through and into the ecosystem. By plotting this "lost" trace it possible to assess its composition which is either 97% cellulose and 3% humic acid or 92% and 8% lignin. This has important implications for what controls the organic matter balance of peatlands and it suggests that the oxidation state (OR) of peatland is less than 1.

  6. Microbial community structure affects marine dissolved organic matter composition

    Directory of Open Access Journals (Sweden)

    Elizabeth B Kujawinski

    2016-04-01

    Full Text Available Marine microbes are critical players in the global carbon cycle, affecting both the reduction of inorganic carbon and the remineralization of reduced organic compounds back to carbon dioxide. Members of microbial consortia all depend on marine dissolved organic matter (DOM and in turn, affect the molecules present in this heterogeneous pool. Our understanding of DOM produced by marine microbes is biased towards single species laboratory cultures or simplified field incubations, which exclude large phototrophs and protozoan grazers. Here we explore the interdependence of DOM composition and bacterial diversity in two mixed microbial consortia from coastal seawater: a whole water community and a <1.0-μm community dominated by heterotrophic bacteria. Each consortium was incubated with isotopically-labeled glucose for 9 days. Using stable-isotope probing techniques and electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry, we show that the presence of organisms larger than 1.0-μm is the dominant factor affecting bacterial diversity and low-molecular-weight (<1000 Da DOM composition over this experiment. In the <1.0-μm community, DOM composition was dominated by compounds with lipid and peptide character at all time points, confirmed by fragmentation spectra with peptide-containing neutral losses. In contrast, DOM composition in the whole water community was nearly identical to that in the initial coastal seawater. These differences in DOM composition persisted throughout the experiment despite shifts in bacterial diversity, underscoring an unappreciated role for larger microorganisms in constraining DOM composition in the marine environment.

  7. Priming the Dissolved Organic Matter Breakdown in Urban Streams

    Science.gov (United States)

    Parr, T.; Cronan, C. S.; Ohno, T.; Simon, K. S.

    2014-12-01

    Land use and land cover change in the Anthropocene have altered the source, composition, and reactivity of dissolved organic matter (DOM) in aquatic ecosystems around the world. In particular, urbanization increases the abundance of bioavailable DOM in streams. This bioavailable DOM may increase the utilization of less bioavailable pools of DOM via the "priming effect." The priming effect is a phenomenon whereby the addition of a small amount of labile DOM can increase or decrease the breakdown rate of less bioavailable DOM - positive and negative priming respectively. Our research tests priming as one potential mechanism altering DOM composition and increasing its bioavailability in urban streams. We measured DOM degradation during 30-day incubations in samples from a small urban stream and two microbial DOM sources mixed with DOM from a small stream dominated by less microbial allochthonous sources. We assessed priming by looking at observed percent biodegradable dissolved organic carbon (BDOC) vs. endmember predicted BDOC. We also investigated the molecular dynamics of priming using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). Using bulk DOC concentration we found evidence that adding small amounts of DOM from an urban stream could increase BDOC by a factor of two to three. At the molecular level, FT-ICR/MS showed that addition of labile DOM may increase the bioavailability of a variety of compound classes including proteins, lipids, and "black carbon." Furthermore, we observed that what is frequently reported as positive or negative priming may be more accurately understood as the net balance of simultaneous positive and negative priming operating on different DOM pools. Our results highlight an important global mechanism by which human activities may alter the composition and reactivity of DOM in fresh waters. Priming the degradation of allochthonous DOM with autochthonous or novel anthropogenic DOM may alter the organic energy

  8. Plasmonics in buried structures.

    Science.gov (United States)

    Romero, I; García de Abajo, F J

    2009-10-12

    We describe plasmon propagation in silica-filled coupled nanovoids fully buried in gold. Propagation bands and band gaps are shown to be tunable through the degree of overlap and plasmon hybridization between contiguous voids. The effect of disorder and fabrication imperfections is thoroughly investigated. Our work explores a novel paradigm for plasmon photonics relying on plasmon modes in metal-buried structures, which can benefit from long propagation distances, cancelation of radiative losses, minimum crosstalk between neighboring waveguides, and maximum optical integration in three-dimensional arrangements.

  9. Fluorescence quantum yields of natural organic matter and organic compounds: Implications for the fluorescence-based interpretation of organic matter composition

    DEFF Research Database (Denmark)

    Wünsch, Urban; Murphy, Kathleen R.; Stedmon, Colin

    2015-01-01

    Absorbance and fluorescence spectroscopy are economical tools for tracing the supply, turnover and fate of dissolved organic matter (DOM). The colored and fluorescent fractions of DOM (CDOM and FDOM, respectively) are linked by the apparent fluorescence quantum yield (AQY) of DOM, which reflects ...... to confirm matches was limited due to multiple compounds exhibiting very similar spectra. This reiterates the fact that spectral similarity alone is insufficient evidence of the presence of particular compounds, and additional evidence is required...

  10. Vehicular emissions of organic particulate matter in Sao Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    B. S. Oyama

    2015-12-01

    Full Text Available Vehicular emissions have a strong impact on air pollution in big cities. Many factors affect these emissions: type of vehicle, type of fuel, cruising velocity, and brake use. This study focused on emissions of organic compounds by Light (LDV and Heavy (HDV duty vehicle exhaust. The study was performed in the city of Sao Paulo, Brazil, where vehicles run on different fuels: gasoline with 25 % ethanol (called gasohol, hydrated ethanol, and diesel (with 5 % of biodiesel. The vehicular emissions are an important source of pollutants and the principal contribution to fine particulate matter (smaller than 2.5 μm, PM2.5 in Sao Paulo. The experiments were performed in two tunnels: Janio Quadros (TJQ where 99 % of the vehicles are LDV, and Rodoanel Mario Covas (TRA where up to 30 % of the fleet was HDV. The PM2.5 samples were collected on quartz filters in May and July 2011 at TJQ and TRA, respectively, using two samplers operating in parallel. The samples were analyzed by Thermal-Desorption Proton-Transfer-Reaction Mass-Spectrometry (TD-PTR-MS, and by Thermal-Optical Transmittance (TOT. The organic aerosol (OA desorbed at TD-PTR-MS represented around 30 % of the OA estimated by the TOT method, mainly due to the different desorption temperatures, with a maximum of 870 and 350 °C for TOT and TD-PTR-MS, respectively. Average emission factors (EF organic aerosol (OA and organic carbon (OC were calculated for HDV and LDV fleet. We found that HDV emitted more OA and OC than LDV, and that OC emissions represented 36 and 43 % of total PM2.5 emissions from LDV and HDV, respectively. More than 700 ions were identified by TD-PTR-MS and the EF profiles obtained from HDV and LDV exhibited distinct features. Nitrogen-containing compounds measured in the desorbed material up to 350 °C contributed around 20 % to the EF values for both types of vehicles, possibly associated with incomplete fuel burning. Additionally, 70 % of the organic compounds measured from the

  11. Vehicular emissions of organic particulate matter in Sao Paulo, Brazil

    Science.gov (United States)

    Oyama, B. S.; Andrade, M. F.; Herckes, P.; Dusek, U.; Röckmann, T.; Holzinger, R.

    2015-12-01

    Vehicular emissions have a strong impact on air pollution in big cities. Many factors affect these emissions: type of vehicle, type of fuel, cruising velocity, and brake use. This study focused on emissions of organic compounds by Light (LDV) and Heavy (HDV) duty vehicle exhaust. The study was performed in the city of Sao Paulo, Brazil, where vehicles run on different fuels: gasoline with 25 % ethanol (called gasohol), hydrated ethanol, and diesel (with 5 % of biodiesel). The vehicular emissions are an important source of pollutants and the principal contribution to fine particulate matter (smaller than 2.5 μm, PM2.5) in Sao Paulo. The experiments were performed in two tunnels: Janio Quadros (TJQ) where 99 % of the vehicles are LDV, and Rodoanel Mario Covas (TRA) where up to 30 % of the fleet was HDV. The PM2.5 samples were collected on quartz filters in May and July 2011 at TJQ and TRA, respectively, using two samplers operating in parallel. The samples were analyzed by Thermal-Desorption Proton-Transfer-Reaction Mass-Spectrometry (TD-PTR-MS), and by Thermal-Optical Transmittance (TOT). The organic aerosol (OA) desorbed at TD-PTR-MS represented around 30 % of the OA estimated by the TOT method, mainly due to the different desorption temperatures, with a maximum of 870 and 350 °C for TOT and TD-PTR-MS, respectively. Average emission factors (EF) organic aerosol (OA) and organic carbon (OC) were calculated for HDV and LDV fleet. We found that HDV emitted more OA and OC than LDV, and that OC emissions represented 36 and 43 % of total PM2.5 emissions from LDV and HDV, respectively. More than 700 ions were identified by TD-PTR-MS and the EF profiles obtained from HDV and LDV exhibited distinct features. Nitrogen-containing compounds measured in the desorbed material up to 350 °C contributed around 20 % to the EF values for both types of vehicles, possibly associated with incomplete fuel burning. Additionally, 70 % of the organic compounds measured from the aerosol

  12. Do aggregate stability and soil organic matter content increase following organic inputs?

    Science.gov (United States)

    Lehtinen, Taru; Gísladóttir, Guðrún; van Leeuwen, Jeroen P.; Bloem, Jaap; Steffens, Markus; Vala Ragnarsdóttir, Kristin

    2014-05-01

    Agriculture is facing several challenges such as loss of soil organic matter (SOM); thus, sustainable farming management practices are needed. Organic farming is growing as an alternative to conventional farming; in Iceland approximately 1% and in Austria 16% of utilized agricultural area is under organic farming practice. We analyzed the effect of different farming practices (organic, and conventional) on soil physicochemical and microbiological properties in grassland soils in Iceland and cropland soils in Austria. Organic farms differed from conventional farms by absence of chemical fertilizers and pesticide use. At these farms, we investigated soil physicochemical (e.g. soil texture, pH, CAL-extractable P and K) and microbiological properties (fungal and bacterial biomass and activity). The effects of farming practices on soil macroaggregate stability and SOM quantity, quality and distribution between different fractions were studied following a density fractionation. In Iceland, we sampled six grassland sites on Brown (BA) and Histic (HA) Andosols; two sites on extensively managed grasslands, two sites under organic and two sites under conventional farming practice. In Austria, we sampled four cropland sites on Haplic Chernozems; two sites under organic and two sites under conventional farming practice. We found significantly higher macroaggregate stability in the organic compared to the conventional grasslands in Iceland. In contrast, slightly higher macroaggregation in conventional compared to the organic farming practice was found in croplands in Austria, although the difference was not significant. Macroaggregates were positively correlated with fungal biomass in Iceland, and with Feo and fungal activity in Austria. In Austria, SOM content and nutrient status (except for lower CAL-extractable P at one site) were similar between organic and conventional farms. Our results show that the organic inputs may have enhanced macroaggregation in organic farming

  13. CO2 mitigation potential in farmland of China by altering current organic matter amendment pattern

    Institute of Scientific and Technical Information of China (English)

    CADISCH; Georg

    2010-01-01

    The estimation of the global warming mitigation potential in terrestrial ecosystems is of great importance for decision makers to adopt measures to increase soil organic carbon (SOC) as well as to reduce greenhouse gas (GHGs) emissions. In this paper, we compiled data published in peer-reviewed journals, and conducted a holistic analysis of the effects of organic matter amendment on soil organic carbon sequestration, methane (CH4) and nitrous oxide (N2O) emissions in paddy and upland systems. Results showed that organic matter amendment increased soil organic carbon content, and apparent conversion rate of organic matter carbon to soil organic carbon in paddies was constant, while that in uplands decreased along with amendment years at 25 years time scale. Organic matter amendment during the rice season led to large CH4-C emissions, e.g on average 99.5 g CH4-C per kg organic carbon input under intermittent flood conditions, and 191.7 g CH4-C per kg organic carbon input under continuous flood conditions, respectively. By alteration of organic matter amendment from rice season to off-rice upland crop season, estimated CH4-C emissions in China could be cut by 3.5 Tg yr-1, accounting for 63% of current CH4-C emissions (5.5 Tg). If organic matter amendment percentage was increased from current 30% to future 50% of organic matter production and by alteration of organic matter amendment from rice season to off-rice upland crop season, the equivalent CO2-C mitigation potential in farmland of China would be 49.2 Tg yr-1 at the 10th year organic matter amendment and 36.0 Tg yr-1 at the 30th year amendment. These findings are important not only for China but also for the other rice production countries to increase farmland global warming mitigation.

  14. Formation and Water Stability of Aggregates in Red Soils as Affected by Organic Matter

    Institute of Scientific and Technical Information of China (English)

    ZHANGMINGKUI等; M.J.WILSON; 等

    1996-01-01

    The water stability of aggregates in various size classes separated from 18 samples of red soils under different managements,and the mechanisms responsible for the formation of waer-stable soil aggregates were studied.The results showed that the water stbility of soil aggregates declined with increasing size,especially for the low organic matter soils.Organic matter plays a key role in the formation of water-stable soil aggregates.The larger the soil aggregate size.the greater the impact of organic matter on the water stability of soil aggregates.Removal of organic matter markedly disintegrated the large water-stable aggregates(>2.0mm)and increased the small ones(2.0mm)were mainly glued up by organic mater,Both free oxides and organic matter contribute to the formation and water stability of aggregates in red soils.

  15. Cosorption study of organic pollutants and dissolved organic matter in a soil

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Cespedes, F. [Department of Inorganic Chemistry, University of Almeria, La Canada de San Urbano s/n, 04120 Almeria (Spain); Fernandez-Perez, M. [Department of Inorganic Chemistry, University of Almeria, La Canada de San Urbano s/n, 04120 Almeria (Spain)]. E-mail: mfernand@ual.es; Villafranca-Sanchez, M. [Department of Inorganic Chemistry, University of Almeria, La Canada de San Urbano s/n, 04120 Almeria (Spain); Gonzalez-Pradas, E. [Department of Inorganic Chemistry, University of Almeria, La Canada de San Urbano s/n, 04120 Almeria (Spain)

    2006-08-15

    In this study we have evaluated the effects of dissolved organic matter (DOM) on sorption of imidacloprid, 3,4-dichloroaniline (3,4-DCA) and 4-bromoaniline (4-BA) on a typical calcareous soil (Luvic Xerosol) from south-eastern Spain. Two different types of DOM were used, that is to say, dissolved natural organic matter extracts from a commercial peat (DNOM) and a high-purity tannic acid (TA) solution. The experiments were carried out in a 0.01 M CaCl{sub 2} aqueous medium at 25 deg. C. The results indicated that the presence of both DNOM and TA, over a concentration range of 15-100 mg L{sup -1}, produced an increase in the amount of 3,4-DCA and 4-BA sorbed and a decrease in the amount of imidacloprid retained on the soil studied. A modified distribution coefficient, K {sub doc}, has been proposed as a safer parameter for soil sorption predictions of organic pollutants and it could be of help to model the fate of these in the environment. - Cosorption of organic pollutants and DOM.

  16. Could organic matter have been preserved on Mars for 3.5 billion years?

    Science.gov (United States)

    Kanavarioti, Anastassia; Mancinelli, Rocco L.

    1990-01-01

    About 3.5 Gyr ago, when it is thought that Mars and earth had similar climates, biological evolution on earth had made considerable progress, such that life was abundant. It is therefore surmised that prior to this time period, the advent of chemical evolution and subsequent origin of life occurred on earth and may have occurred on Mars. Analysis for organic compounds in the soil buried beneath the Martian surface may yield useful information regarding the occurrence of chemical evolution and possibly biological evolution. Calculations based on the stability of amino acids lead to the conclusion that remnants of these compounds, if they existed on Mars 3.5 Gyr ago, might have been preserved buried beneath the surface oxidizing layer. For example, if phenylalanine, an amino acid of average stability, existed on Mars 3.5 Gyr ago, then 1.6 percent would remain buried today. Martian soil may exist from remnants of meteoritic and cometary bombardment, assuming that 1 percent of the organics survived impact.

  17. Microbially-mediated fluorescent organic matter transformations in the deep ocean. Do the chemical precursors matter?

    Directory of Open Access Journals (Sweden)

    Fran L. Aparicio

    2015-12-01

    Full Text Available The refractory nature of marine dissolved organic matter (DOM increases while it travels from surface waters to the deep ocean. This resistant fraction is in part composed of fluorescent humic-like material, which is relatively difficult to metabolize by deep water prokaryotes, and it can also be generated by microbial activity. It has been recently argued that microbial production of new fluorescent DOM (FDOM requires the presence of humic precursors in the surrounding environment. In order to experimentally test how the chemical quality of the available organic compounds influences the production of new FDOM, three experiments were performed with bathypelagic Atlantic waters. Microbial communities were incubated in three treatments which differed in the quality of the organic compounds added: i glucose and acetate; ii glucose, acetate, essential amino acids and humic acids; and iii humic acids alone. The response of the prokaryotes and the production of FDOM were simultaneously monitored. Prokaryotic abundance was highest in treatments where labile compounds were added. The rate of humic-like fluorescence production scaled to prokaryotic abundance varied depending on the quality of the additions. The precursor compounds affected the generation of new humic-like FDOM, and the cell-specific production of this material was higher in the incubations amended with humic precursors. Furthermore, we observed that the protein-like fluorescence decreased only when fresh amino acids were added. These findings contribute to the understanding of FDOM variability in deep waters and provide valuable information for studies where fluorescent compounds are used in order to track water masses and/or microbial processes.

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

    Science.gov (United States)

    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.

  19. Carbohydrates in size fractionated dissolved organic matter in a station of the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, L.; DeSouza, F.; Bhosle, N.B.

    of the dissolved organic matter (DOM) were collected using Amicon stirred Ultrafiltration Cell, and analysed for dissolved organic carbon (UDOC), total carbohydrates (UTCHO) and neutral sugars (UNS). UDOC concentrations were relatively higher in HMW fraction...

  20. Changes in functional organization and white matter integrity in the connectome in Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Sule Tinaz

    2017-01-01

    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.

  1. Planktonic organic matter in surficial sediments of the Banda Sea (Indonesia) : a palynological approach

    NARCIS (Netherlands)

    van Waveren, I.M.

    1993-01-01

    The acid resistant microscopic organic matter preserved in marine sediments (palynofacies) represents a small fraction of marine and terrestrial biomass that escaped rapid degradation and recycling to the atmospheric and hydrospheric carbon reservoirs. Palynofacies consists of (1) organic

  2. Biochemical composition of organic matter in UK Midlands catchments: implications for drinking water treatment

    Science.gov (United States)

    Bieroza, M.; Bridgeman, J.; Baker, A.

    2007-12-01

    Insufficient removal of natural organic matter at treatment works can lead to the formation of potentially carcinogenic disinfection by-products (mainly trihalomethanes and haloacetic acids, THMs and HAAs) due to reactions of residual organic matter with chlorine added at the disinfection stage of water treatment process. However, the total organic carbon (TOC) removal efficiency is controlled by the content and character of organic matter in treated water, spatially and temporally dependent (e.g. the ratio of hydrophylic and hydrophobic fractions). Thus, a better understanding of organic matter composition can affect the treatment process strategies, improving the THM formation prediction and the quantification of coagulant and disinfection dosages. Fluorescence analysis of organic matter composition and treatment efficiency has been carried out on raw and partially-treated water samples from catchments in the Midlands region of the UK. The catchments cover an area of different water sources, ranging from upland, peaty-rich subcatchments with coloured, young waters, to agriculturally transformed lowland subcatchments. From the spectrophotometric analysis of raw water it was found that, the abstraction from river with water storage in reservoirs corresponds with a hydrophilic character of organic matter, rather high microbial fraction and high TOC. Opposite properties (hydrophobic, low microbial and variable TOC) are specific for sites with abstraction and storage processes within reservoirs. For direct abstraction from rivers, without water storing in reservoir, a common pattern is intermediate character of organic matter. The fluorescence excitation-emission matrix (EEM) technique was used for the assessment of water treatment works performance (TOC removal) and organic matter characterization. The freshwater organic matter exhibits specific fluorescence properties, with increased intensities of fluorescence in some regions of the EEM, resulting from the water

  3. Chemodiversity of dissolved organic matter in the Amazon Basin

    Science.gov (United States)

    Gonsior, Michael; Valle, Juliana; Schmitt-Kopplin, Philippe; Hertkorn, Norbert; Bastviken, David; Luek, Jenna; Harir, Mourad; Bastos, Wanderley; Enrich-Prast, Alex

    2016-07-01

    Regions in the Amazon Basin have been associated with specific biogeochemical processes, but a detailed chemical classification of the abundant and ubiquitous dissolved organic matter (DOM), beyond specific indicator compounds and bulk measurements, has not yet been established. We sampled water from different locations in the Negro, Madeira/Jamari and Tapajós River areas to characterize the molecular DOM composition and distribution. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) combined with excitation emission matrix (EEM) fluorescence spectroscopy and parallel factor analysis (PARAFAC) revealed a large proportion of ubiquitous DOM but also unique area-specific molecular signatures. Unique to the DOM of the Rio Negro area was the large abundance of high molecular weight, diverse hydrogen-deficient and highly oxidized molecular ions deviating from known lignin or tannin compositions, indicating substantial oxidative processing of these ultimately plant-derived polyphenols indicative of these black waters. In contrast, unique signatures in the Madeira/Jamari area were defined by presumably labile sulfur- and nitrogen-containing molecules in this white water river system. Waters from the Tapajós main stem did not show any substantial unique molecular signatures relative to those present in the Rio Madeira and Rio Negro, which implied a lower organic molecular complexity in this clear water tributary, even after mixing with the main stem of the Amazon River. Beside ubiquitous DOM at average H / C and O / C elemental ratios, a distinct and significant unique DOM pool prevailed in the black, white and clear water areas that were also highly correlated with EEM-PARAFAC components and define the frameworks for primary production and other aspects of aquatic life.

  4. Chemotaxis toward phytoplankton drives organic matter partitioning among marine bacteria.

    Science.gov (United States)

    Smriga, Steven; Fernandez, Vicente I; Mitchell, James G; Stocker, Roman

    2016-02-09

    The microenvironment surrounding individual phytoplankton cells is often rich in dissolved organic matter (DOM), which can attract bacteria by chemotaxis. These "phycospheres" may be prominent sources of resource heterogeneity in the ocean, affecting the growth of bacterial populations and the fate of DOM. However, these effects remain poorly quantified due to a lack of quantitative ecological frameworks. Here, we used video microscopy to dissect with unprecedented resolution the chemotactic accumulation of marine bacteria around individual Chaetoceros affinis diatoms undergoing lysis. The observed spatiotemporal distribution of bacteria was used in a resource utilization model to map the conditions under which competition between different bacterial groups favors chemotaxis. The model predicts that chemotactic, copiotrophic populations outcompete nonmotile, oligotrophic populations during diatom blooms and bloom collapse conditions, resulting in an increase in the ratio of motile to nonmotile cells and in the succession of populations. Partitioning of DOM between the two populations is strongly dependent on the overall concentration of bacteria and the diffusivity of different DOM substances, and within each population, the growth benefit from phycospheres is experienced by only a small fraction of cells. By informing a DOM utilization model with highly resolved behavioral data, the hybrid approach used here represents a new path toward the elusive goal of predicting the consequences of microscale interactions in the ocean.

  5. Pyrolysis-combustion 14C dating of soil organic matter

    Science.gov (United States)

    Wang, Hong; Hackley, Keith C.; Panno, Samuel V.; Coleman, Dennis D.; Liu, Jack Chao-li; Brown, Johnie

    2003-11-01

    Radiocarbon ( 14C) dating of total soil organic matter (SOM) often yields results inconsistent with the stratigraphic sequence. The onerous chemical extractions for SOM fractions do not always produce satisfactory 14C dates. In an effort to develop an alternative method, the pyrolysis-combustion technique was investigated to partition SOM into pyrolysis volatile (Py-V) and pyrolysis residue (Py-R) fractions. The Py-V fractions obtained from a thick glacigenic loess succession in Illinois yielded 14C dates much younger but more reasonable than the counterpart Py-R fractions for the soil residence time. Carbon isotopic composition (δ 13C) was heavier in the Py-V fractions, suggesting a greater abundance of carbohydrate- and protein-related constituents, and δ 13C was lighter in the Py-R fractions, suggesting more lignin- and lipid-related constituents. The combination of 14C dates and δ 13C values indicates that the Py-V fractions are less biodegradation resistant and the Py-R fractions are more biodegradation resistant. The pyrolysis-combustion method provides a less cumbersome approach for 14C dating of SOM fractions. With further study, this method may become a useful tool for analyzing unlithified terrestrial sediments when macrofossils are absent.

  6. Soil microstructure and organic matter: keys for chlordecone sequestration.

    Science.gov (United States)

    Woignier, T; Fernandes, P; Soler, A; Clostre, F; Carles, C; Rangon, L; Lesueur-Jannoyer, M

    2013-11-15

    Past applications of chlordecone, a persistent organochlorine pesticide, have resulted in diffuse pollution of agricultural soils, and these have become sources of contamination of cultivated crops as well as terrestrial and marine ecosystems. Chlordecone is a very stable and recalcitrant molecule, mainly present in the solid phase, and has a strong affinity for organic matter. To prevent consumer and ecosystem exposure, factors that influence chlordecone migration in the environment need to be evaluated. In this study, we measured the impact of incorporating compost on chlordecone sequestration in andosols as a possible way to reduce plant contamination. We first characterized the transfer of chlordecone from soil to plants (radish, cucumber, and lettuce). Two months after incorporation of the compost, soil-plant transfers were reduced by a factor of 1.9-15 depending on the crop. Our results showed that adding compost modified the fractal microstructure of allophane clays thus favoring chlordecone retention in andosols. The complex structure of allophane and the associated low accessibility are important characteristics governing the fate of chlordecone. These results support our proposal for an alternative strategy that is quite the opposite of total soil decontamination: chlordecone sequestration.

  7. Temperature responses of individual soil organic matter components

    Science.gov (United States)

    Feng, Xiaojuan; Simpson, Myrna J.

    2008-09-01

    Temperature responses of soil organic matter (SOM) remain unclear partly due to its chemical and compositional heterogeneity. In this study, the decomposition of SOM from two grassland soils was investigated in a 1-year laboratory incubation at six different temperatures. SOM was separated into solvent extractable compounds, suberin- and cutin-derived compounds, and lignin-derived monomers by solvent extraction, base hydrolysis, and CuO oxidation, respectively. These SOM components have distinct chemical structures and stabilities and their decomposition patterns over the course of the experiment were fitted with a two-pool exponential decay model. The stability of SOM components was also assessed using geochemical parameters and kinetic parameters derived from model fitting. Compared with the solvent extractable compounds, a low percentage of lignin monomers partitioned into the labile SOM pool. Suberin- and cutin-derived compounds were poorly fitted by the decay model, and their recalcitrance was shown by the geochemical degradation parameter (ω - C16/∑C16), which was observed to stabilize during the incubation. The temperature sensitivity of decomposition, expressed as Q10, was derived from the relationship between temperature and SOM decay rates. SOM components exhibited varying temperature responses and the decomposition of lignin monomers exhibited higher Q10 values than the decomposition of solvent extractable compounds. Our study shows that Q10 values derived from soil respiration measurements may not be reliable indicators of temperature responses of individual SOM components.

  8. Dissolved organic matter reduces algal accumulation of methylmercury

    Science.gov (United States)

    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. Spectral Induced Polarization Signature of Soil Organic Matter

    Science.gov (United States)

    Schwartz, Nimrod; Furman, Alex

    2015-04-01

    Although often composing a non-negligible fraction of soil cation exchange capacity (CEC), the impact of soil organic matter (OM) on the electrical properties of soil has not been thoroughly investigated. In this research the impact of soil OM on the spectral induced polarization (SIP) signature of soil was investigated. Electrical and chemical measurements for two experiments using the same soil, one with calcium as the dominant cation and the other with sodium, with different concentration of OM were performed. Our results show that despite the high CEC of OM, a decrease in polarization and an increase in relaxation time with increasing concentration of OM is observed. For the soil with calcium as the dominant cation, the decreases in polarization and the increase in relaxation time were stronger. We explain these non-trivial results by accounting for the interactions between the OM and the soil minerals. We suggest that the formation of organo-mineral complexes reduce ionic mobility, explaining both the decrease in polarization and the increase in relaxation time. These results demonstrate the important role of OM on SIP response of soil, and call for a further research in order to establish a new polarization model that will include the impact of OM on soil polarization.

  10. On the spectral induced polarization signature of soil organic matter

    Science.gov (United States)

    Schwartz, N.; Furman, A.

    2015-01-01

    Although often composing a non-negligible fraction of soil cation exchange capacity (CEC), the impact of soil organic matter (OM) on the electrical properties of soil has not been thoroughly investigated. In this research the impact of soil OM on the spectral induced polarization (SIP) signature of soil was investigated. Electrical and chemical measurements for two experiments using the same soil, one with calcium as the dominant cation and the other with sodium, with different concentration of OM were performed. Our results show that despite the high CEC of OM, a decrease in polarization and an increase in relaxation time with increasing concentration of OM is observed. For the soil with calcium as the dominant cation, the decreases in polarization and the increase in relaxation time were stronger. We explain these non-trivial results by accounting for the interactions between the OM and the soil minerals. We suggest that the formation of organo-mineral complexes reduce ionic mobility, explaining both the decrease in polarization and the increase in relaxation time. These results demonstrate the important role of OM on SIP response of soil, and call for a further research in order to establish a new polarization model that will include the impact of OM on soil polarization.

  11. Priming and substrate quality interactions in soil organic matter models

    Directory of Open Access Journals (Sweden)

    T. Wutzler

    2012-12-01

    Full Text Available Interactions between different qualities of soil organic matter (SOM affecting their turnover are rarely represented in models. In this study we propose three mathematical strategies at different levels of abstraction for representing those interactions. Implementing these strategies into the Introductory Carbon Balance Model (ICBM and applying them to several scenarios of litter input show that the different levels of abstraction are applicable on different time scales. We present a simple one-parameter equation of substrate limitation applicable at decadal time scale that is straightforward to implement into other models of SOM dynamics. We show how substrate quality interactions can explain priming effects, acceleration of turnover times in FACE experiments, and the slowdown of decomposition in long-term bare fallow experiments as an effect of energy limitation of microbial biomass. The mechanisms of those interactions need to be further scrutinized empirically for a more complete understanding. Overall, substrate quality interactions offer a valuable way of understanding and quantitatively modelling SOM dynamics.

  12. Vulcanization of lipidic organic matter in reactive-iron deficient environments: a possible enhancement for the storage of hydrogen-rich organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Tribovillard, N.P.; Desprairies, A. (Paris-11 Univ., 91 - Orsay (France)); Lallier-Verges, E. (Orleans Univ., 45 (France)); Bertrand, P. (Bordeaux-1 Univ., 33 - Talence (France))

    1994-11-01

    Geochemists have highlighted an important mechanism for kerogen formation: the early, HS[sup -]/H[sub 2]S - induced, vulcanization which protects organic-sulfur compounds from bacterial degradation. We base our study on two formations in which organic-matter accumulation is thought to result principally from organic-walled-plankton productivity. When reactive iron was a limiting factor for Fe-sulfide formation, organic matter was enriched in sulfur, and TOC and HI values were higher. We suggest the lack of reactive iron could promote vulcanization of organic matter, helping its storage and keeping HI at high values. Bottom-water anoxia could promote this mechanism (positive feedback effect). (authors). 11 refs., 2 figs., 1 tab.

  13. Bioavailability and export of dissolved organic matter from a tropical river during base- and stormflow conditions

    Science.gov (United States)

    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...

  14. Origin and fate of organic matter in sandy soils along a primary vegetation succession

    NARCIS (Netherlands)

    Nierop, K.

    1999-01-01

    Until now little is known about the role vegetation plays in the organic matter formation, particularly at the molecular level. Most ecosystems have a long history, which is unknown or too complex to find distinct relations between vegetation and the chemical composition of soil organic matter. To g

  15. Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

    NARCIS (Netherlands)

    Sagrilo, E.

    2014-01-01

    Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns Edvaldo Sagrilo Summary Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There

  16. Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

    NARCIS (Netherlands)

    Sagrilo, E.

    2014-01-01

    Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns Edvaldo Sagrilo Summary Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There

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

    Science.gov (United States)

    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...

  18. Mean residence time of soil organic matter associated with kaolinite and smectite

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.; Buurman, P.; Plicht, J. van der; Wattel, E.; Breemen, N. van

    To gain insight into the effect of clay mineralogy on the turnover of organic matter, we analysed the C-14 activity of soil organic matter associated with clay in soils dominated by kaolinite and smectite in natural savanna systems in seven countries. Assuming that carbon inputs and outputs are in

  19. Processes controlling the production of aromatic water-soluble organic matter during litter decomposition

    NARCIS (Netherlands)

    Klotzbücher, T.; Kaiser, K.; Filley, T.R.; Kalbitz, K.

    2013-01-01

    Dissolved organic matter (DOM) plays a fundamental role for many soil processes. For instance, production, transport, and retention of DOM control properties and long-term storage of organic matter in mineral soils. Production of water-soluble compounds during the decomposition of plant litter is a

  20. Differential recycling of coral and algal dissolved organic matter via the sponge loop

    NARCIS (Netherlands)

    Rix, L.; de Goeij, J.M.; Van Oevelen, D.; Struck, U.; Al-Horani, F.A.; Wild, C.; Naumann, M.S.

    2016-01-01

    1. Corals and macroalgae release large quantities of dissolved organic matter (DOM), one ofthe largest sources of organic matter produced on coral reefs. By rapidly taking up DOM andtransforming it into particulate detritus, coral reef sponges are proposed to play a key role intransferring the energ

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

    Science.gov (United States)

    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...

  2. Dissolved organic matter and lake metabolism. Technical progress report, 1 July 1975--30 June 1976

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, R. G.

    1976-01-01

    Progress is reported in the following areas of research: interactions of dissolved organic matter with inorganic nutrient cycling; regulation of the photosynthetic and decompositional metabolism of micro- and macroflora; regulatory mechanisms of growth and rates of carbon cycling; and fate of detrital dissolved and particulate organic matter. (HLW)

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

    DEFF Research Database (Denmark)

    Catalá, Teresa Serrano; Reche, Isabel; Fuentes-Lema, Antonio;

    2015-01-01

    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 i...

  4. Mean residence time of soil organic matter associated with kaolinite and smectite

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.; Buurman, P.; Plicht, van der J.; Wattel, J.T.; Breemen, van N.

    2003-01-01

    To gain insight into the effect of clay mineralogy on the turnover of organic matter, we analysed the C-14 activity of soil organic matter associated with clay in soils dominated by kaolinite and smectite in natural savanna systems in seven countries. Assuming that carbon inputs and outputs are in e

  5. Occurrence and abundance of carbohydrates and amino compounds in sequentially extracted labile soil organic matter fractions.

    Science.gov (United States)

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

    Science.gov (United States)

    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...

  7. Characterization and beneficiation of the Egyptian black shale for possible extraction of organic matter

    Institute of Scientific and Technical Information of China (English)

    Abd El-Rahiem F.H.; Hassan M.S.; Selim K.A.; Abdel-Khalek N.A

    2014-01-01

    The present paper focuses on obtaining concentrate enriched with organic matter that could be suitable for a retorting process from black shale; this is black shale from the Safaga area on the Red Sea Coast. X-ray diffraction and optical polarising microscope are used in evaluating black shale minerals. Attrition scrubbing and flotation were conducted for enrichment of organic matter in the black shale sample. Mineralogical studies revealed that black shale samples contain bituminous calcareous clay stone, quartz, apatite and pyrite. Rabah mine black shale contains 28% organic matter. The results of the different separation techniques indicate that attrition and flotation techniques successively enriched the organic matter in the black shale. The organic matter could be enriched in the black shale and obtained a concen-trate with 59%assaying and 85%recovery.

  8. Abiotic emissions of methane and reduced organic compounds from organic matter

    Science.gov (United States)

    Roeckmann, T.; Keppler, F.; Vigano, I.; Derendorp, L.; Holzinger, R.

    2012-12-01

    Recent laboratory studies show that the important greenhouse gas methane, but also other reduced atmospheric trace gases, can be emitted by abiotic processes from organic matter, such as plants, pure organic compounds and soils. It is very difficult to distinguish abiotic from biotic emissions in field studies, but in laboratory experiments this is easier because it is possible to carefully prepare/sterilize samples, or to control external parameters. For example, the abiotic emissions always show a strong increase with temperature when temperatures are increased to 70C or higher, well above the temperature optimum for bacterial activity. UV radiation has also been clearly shown to lead to emission of methane and other reduced gases from organic matter. Interesting information on the production mechanism has been obtained from isotope studies, both at natural abundance and with isotope labeling. For example, the methoxyl groups of pectin were clearly identified to produce methane. However, analysis of the isotopic composition of methane from natural samples clearly indicates that there must be other molecular mechanisms that lead to methane production. Abiotic methane generation could be a ubiquitous process that occurs naturally at low rates from many different sources.

  9. Soil organic matter on citrus plantation in Eastern Spain

    Science.gov (United States)

    Cerdà, Artemi; Pereira, Paulo; Novara, Agata; Prosdocimi, Massimo

    2015-04-01

    Citrus plantations in Eastern Spain are the main crop and Valencia region is the largest world exporter. The traditional plantation are located on flood irrigated areas and the new plantation are located on slopes were drip irrigation is the source of the wetting. It has been demonstrate that the citrus plantations contribute to high erosion rates on slopes (Cerdà et al., 2009b) as it is usual on agriculture land (Cerdà et al., 2009a), but when organic farming is present the soil erosion is much lower (Cerdà and Jurgensen, 2008; Cerdà et al., 2009; Cerdà and Jurgensen, 2011). This is a worldwide phenomenon (Wu et al., 2007; Wu et al., 2011; Xu et al., 2010; Xu et al., 2012a; Xu et al., 2012b), which are a key factor of the high erosion rates in rural areas (García Orenes et al., 2009: García Orenes et al., 20010; García Orenes et al., 2012; Haregewyn et al., 2013; Zhao et al., 2013). The key factor of the contrasted response of soils to the rain in citrus is the organic matter cover. This is why the Soil Erosion and Degradation Research Team developed a survey to determine the soil erosion rates on citrus orchards under different managements. A hundred of samples were collected in a citrus plantation on slope under conventional management (Chemical management), one on organic farming, one on traditional flood irrigated organic farming and one on traditional chemical flooding farm. The organic farming soils were treated with 10000 Kg ha-1 of manure yearly. The results show that the mean soil organic matter content was 1.24 %, 3.54%, 5,43% and 2.1% respectively, which show a clear impact of organic farming in the recovery of the soil organic matter. meanwhile the on the slopes and the flood-irrigated soils are Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and PREVENTING AND REMEDIATING DEGRADATION OF SOILS IN EUROPE THROUGH LAND CARE (RECARE)FP7- ENV-2013- supported this research. References Cerdà, A., Flanagan, D.C., le Bissonnais

  10. Changes in dissolved organic matter during stream drying and rewetting

    Science.gov (United States)

    von Schiller, D.; Acuña, V.; Graeber, D.; Martí, E.; Ribot, M.; Sabater, S.; Timoner, X.; Tockner, K.

    2012-04-01

    Dissolved organic matter (DOM) is a complex mixture of organic compounds, which represents an essential source of carbon (C) and nutrients in aquatic ecosystems. In addition, DOM can play a key ecological role by modifying the optical properties of waters, mediating the availability of metals and influencing trophic food web structure. While the effects of drying and rewetting on DOM dynamics in terrestrial soils is a well studied subject, less is known about its effects in aquatic ecosystems, especially in streams. This is an important gap of knowledge since temporary streams that naturally cease to flow are found worldwide. Moreover, many streams with perennial flow are currently facing flow intermittency due to the effects of water extraction or changes in land-use and climate. The aim of this study was to evaluate the effects of stream flow intermittency on the spatial and temporal variability of DOM. The study was performed in a 300-m long reach of the Fuirosos stream (Catalonia, NE Spain) during the drying (June to July) and rewetting (October to November) phases. We sampled at several points along the study reach every 3 to 4 days. We assessed DOM amount by measuring the concentration of dissolved organic C and nitrogen (N). We characterized DOM composition using spectroscopic measurements, size-exclusion chromatography and C:N stoichiometry. Results showed two markedly distinct biogeochemical shifts between the drying and the rewetting phases. During the transition from continuous to fragmented flow we observed an increase in the magnitude and spatial variability of DOM concentrations and DOM was dominated by compounds from aquatic origin. After flow recovery, we also observed a pronounced increase in DOM concentration, but during this hydrologic phase DOM was dominated by compounds of terrestrial origin. Taken together, these results emphasize the relevance of flow intermittency in regulating stream DOM dynamics not only in terms of its availability but

  11. Where is DNA preserved in soil organic matter?

    Science.gov (United States)

    Zaccone, Claudio; Beneduce, Luciano; Plaza, César

    2015-04-01

    Deoxyribonucleic acid (DNA) consists of long chains of alternating sugar and phosphate residues twisted in the form of a helix. Upon decomposition of plant and animal debris, this nucleic acid is released into the soil, where its fate is still not completely understood. In fact, although DNA is one of the organic compounds from living cells that is apparently broken down rapidly in soils, it is also potentially capable of being incorporated in (or interact with) the precursors of humic molecules. In order to track DNA occurrence in soil organic matter (SOM) fractions, an experiment was set up as a randomized complete block design with two factors, namely biochar addition and organic amendment. In particular, biochar (BC), applied at a rate of 20 t/ha, was combined with municipal solid waste compost (BC+MC) at a rate equivalent to 75 kg/ha of potentially available N, and with sewage sludge (BC+SS) at a rate equivalent to 75 kg/ha of potentially available N. Using a physical fractionation method, free SOM located between aggregates (unprotected C pool; FR), SOM occluded within macroaggregates (C pool weakly protected by physical mechanisms; MA), SOM occluded within microaggregates (C pool strongly protected by physical mechanisms; MI), and SOM associated with the mineral fractions (chemically-protected C pool; MIN) were separated from soil samples. DNA was then isolated from each fraction of the two series, as well as from the unamended soil (C) and from the bulk soils (WS), using Powersoil DNA isolation kit (MoBio, CA, USA) with a modified protocol. Data clearly show that the DNA survived the SOM fractionation, thus suggesting that physical fractionation methods create less artifacts compared to the chemical ones. Moreover, in both BC+MC and BC+SS series, most of the isolated DNA was present in the FR fraction, followed by the MA and the MI fractions. No DNA was recovered from the MIN fraction. This finding supports the idea that most of the DNA occurring in the SOM

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

    Science.gov (United States)

    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. Fouling of nanofiltration membrane by effluent organic matter: characterization using different organic fractions in wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHANG Liqing; WANG Lei; ZHANG Gang; WANG Xudong

    2009-01-01

    The UF membrane with molecular weight cutoff (MWCO) ranging from 2 kDa to 100 kDa and XAD-8 resin were employed to identify the characteristic of molecular weight (MW) distribution of wastewater effluent organic matter (EfOM) in terms of TOC and UV254, as well as the amounts of the hydrophilic/hydrophobic organic fractions in different MW ranges. Then, the nanofiltration (NF) membrane fouling experiments were carried out using the above fractionated water to investigate the effect of MW distribution and hydrophilic/hydrophobic characteristics of EfOM on the membrane flux decline using the fractionated water samples above. The experimental results have shown that 45.61% of the total organics belongs to the low MW one, among which the percentage of the hydrophilic organics with low MW (less than 2 kDa) was up to 28.07%, while that of the hydrophobic organics was 17.54%. In particular, the hydrophilic fraction was found to be the most abundant fraction in the effluents. MW distribution has a significant effect on the membrane fouling. When the MW was less than 30 kDa, the lower the MW, the larger was the specific flux decline, while in the case of MW higher than 30 kDa, the higher the MW, the larger was the specific flux decline, and the decline degree of low MW organics was larger than the high MW one. With the same MW distribution range, specific flux decline of the hydrophilic organic was considerably slower than that of the hydrophobic organic, which indicated that the hydrophobic organic fractions dominantly contribute to the flux decline.

  14. Transport of organic contaminants in subsoil horizons and effects of dissolved organic matter related to organic waste recycling practices.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  16. Temperature Responses of Soil Organic Matter Components With Varying Recalcitrance

    Science.gov (United States)

    Simpson, M. J.; Feng, X.

    2007-12-01

    The response of soil organic matter (SOM) to global warming remains unclear partly due to the chemical heterogeneity of SOM composition. In this study, the decomposition of SOM from two grassland soils was investigated in a one-year laboratory incubation at six different temperatures. SOM was separated into solvent- extractable compounds, suberin- and cutin-derived compounds, and lignin monomers by solvent extraction, base hydrolysis, and CuO oxidation, respectively. These SOM components had distinct chemical structures and recalcitrance, and their decomposition was fitted by a two-pool exponential decay model. The stability of SOM components was assessed using geochemical parameters and kinetic parameters derived from model fitting. Lignin monomers exhibited much lower decay rates than solvent-extractable compounds and a relatively low percentage of lignin monomers partitioned into the labile SOM pool, which confirmed the generally accepted recalcitrance of lignin compounds. Suberin- and cutin-derived compounds had a poor fitting for the exponential decay model, and their recalcitrance was shown by the geochemical degradation parameter which stabilized during the incubation. The aliphatic components of suberin degraded faster than cutin-derived compounds, suggesting that cutin-derived compounds in the soil may be at a higher stage of degradation than suberin- derived compounds. The temperature sensitivity of decomposition, expressed as Q10, was derived from the relationship between temperature and SOM decay rates. SOM components exhibited varying temperature responses and the decomposition of the recalcitrant lignin monomers had much higher Q10 values than soil respiration or the solvent-extractable compounds decomposition. Our study shows that the decomposition of recalcitrant SOM is highly sensitive to temperature, more so than bulk soil mineralization. This observation suggests a potential acceleration in the degradation of the recalcitrant SOM pool with global

  17. Concurrent photolytic degradation of aqueous methylmercury and dissolved organic matter.

    Science.gov (United States)

    Fleck, Jacob A; Gill, Gary; Bergamaschi, Brian A; Kraus, Tamara E C; Downing, Bryan D; Alpers, Charles N

    2014-06-15

    Monomethyl mercury (MeHg) is a potent neurotoxin that threatens ecosystem viability and human health. In aquatic systems, the photolytic degradation of MeHg (photodemethylation) is an important component of the MeHg cycle. Dissolved organic matter (DOM) is also affected by exposure to solar radiation (light exposure) leading to changes in DOM composition that can affect its role in overall mercury (Hg) cycling. This study investigated changes in MeHg concentration, DOM concentration, and the optical signature of DOM caused by light exposure in a controlled field-based experiment using water samples collected from wetlands and rice fields. Filtered water from all sites showed a marked loss in MeHg concentration after light exposure. The rate of photodemethylation was 7.5×10(-3)m(2)mol(-1) (s.d. 3.5×10(-3)) across all sites despite marked differences in DOM concentration and composition. Light exposure also caused changes in the optical signature of the DOM despite there being no change in DOM concentration, indicating specific structures within the DOM were affected by light exposure at different rates. MeHg concentrations were related to optical signatures of labile DOM whereas the percent loss of MeHg was related to optical signatures of less labile, humic DOM. Relationships between the loss of MeHg and specific areas of the DOM optical signature indicated that aromatic and quinoid structures within the DOM were the likely contributors to MeHg degradation, perhaps within the sphere of the Hg-DOM bond. Because MeHg photodegradation rates are relatively constant across freshwater habitats with natural Hg-DOM ratios, physical characteristics such as shading and hydrologic residence time largely determine the relative importance of photolytic processes on the MeHg budget in these mixed vegetated and open-water systems. Published by Elsevier B.V.

  18. Nanoscale Structure of Organic Matter Could Explain Litter Decomposition

    Science.gov (United States)

    Papa, G.; Adani, F.

    2014-12-01

    According to the literature biochemical catalyses are limited in their actions because of the complex macroscopic and, above all, microscopic structures of cell wall that limit mass transportation (i.e. 3D structure). Our study on energy crop showed that plant digestibility increased by modifying the 3D cell wall microstructure. Results obtained were ascribed to the enlargement, such as effectively measured, of the pore spaces between cellulose fibrils. Therefore we postulated that 3 D structure of plant residues drives degradability in soil determining its recalcitrance in short time. Here we focused on the drivers of short-term decomposition of organic matter (plant residues) in soils evaluating the architecture of plant tissues, captured via measurements of the microporosiy of the cell walls. Decomposition rates of a wide variety of biomass types were studied conducting experiments in both aerobic and anaerobic environments. Different analytical approaches were applied in order to characterize biomass at both chemical and physical level. Combined statistical approaches were used to examine the relationships between carbon mineralization and chemical/physical characteristics. The results revealed that degradation was significantly and negatively correlated with the micro-porosity surface (MiS) (surface of pores of 0.3-1.5 nm of diameter). The multiple regressions performed by using partial least square model enabled describing biomass biodegradability under either aerobic and anaerobic condition by using micro-porosity and aromatic-C content (assumed to be representative of lignin) as independent variables (R2 =0.97, R2cv =0.95 for aerobic condition; R2 =0.99, R2cv =0.98 for anaerobic condition, respectively). These results corroborate the hypothesis that plant tissues are physically protected from enzymatic attack by a microporous "sheath" that limit penetration into cell wall, and demonstrate the key role played by aromatic carbon, because of its chemical

  19. Soil organic matter as sole indicator of soil degradation.

    Science.gov (United States)

    Obalum, S E; Chibuike, G U; Peth, S; Ouyang, Y

    2017-04-01

    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 soil that impairs its quality. This paper aims at providing a generalized assessment of the current state of knowledge on the usefulness of SOM in monitoring soil degradation, based on its influence on the physical, chemical and biological properties and processes of soils. Emphasis is placed particularly on the effect of SOM on soil structure and availability of plant nutrients. Although these properties are discussed separately, the soil system is of dynamic and interactive nature, and changes in one property will likely affect other soil properties as well. Thus, functions of SOM almost always affect various soil properties and processes and engage in multiple reactions. In view of its role in soil aggregation and erosion control, in availability of plant nutrients and in ameliorating other forms of soil degradation than erosion, SOM has proven to be an important indicator of soil degradation. It has been suggested, however, that rather than the absolute amount, temporal change and potential amount of SOM be considered in its use as indicator of soil degradation, and that SOM may not be an all-purpose indicator. Whilst SOM remains a candidate without substitute as long as a one-parameter indicator of soil degradation is needed, narrowing down to the use of its labile and microbial components could be more appropriate, since early detection is important in the control and management of soil degradation.

  20. Hydrological controls on rate of organic matter mineralization in peats

    Science.gov (United States)

    Ghezzehei, Teamrat; Arnold, Chelsea; Asefaw Berhe, Asmeret

    2016-04-01

    The predominant factor that ties together the formation and persistence of peat soils across regions is their dependence on localized hydrology. Hydrology also plays a dominant role in the relative strength of peatlands as sinks for atmospheric carbon dioxide and sources of methane, and thus on peatland net climate impact. Drying of peat soils by climate change and/or drainage is typically followed by reduction in methane emissions. However, this may easily be offset by the increase in carbon dioxide production. Therefore, mechanistic understanding of peatland hydrology and its association with carbon cycling is a prerequisite for assessing vulnerability of peats to disturbances and for incorporating the associated feedbacks in carbon-climate models. We will present physically based model that ties together the structure of peat soils (mainly pore size distribution and mechanical stability) to rates of aerobic and anaerobic decomposition over a wide range of soil water potentials. Peats consist of hierarchical structure with clear separation of the pores into a population of micropores within clumps of organic matter and/or soil aggregates and a group of macropores between clumps and/or aggregates. This essentially partitions the carbon stock in peat soils in to multiple pools that become mineralizable at disparate water potential ranges. While the carbon in macropores can readily be decomposed by aerobic microorganisms when the soil is only slightly drained, the carbon in fine pores remains largely protected from aerobic microbes until the water potential exceeds a threshold that lets in oxygen. In this presentation we will show the mathematical development of the model and illustrative examples that compare projections with data derived from the literature.

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

    Science.gov (United States)

    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

  2. Natural organic matter and the event horizon of mass spectrometry.

    Science.gov (United States)

    Hertkorn, N; Frommberger, M; Witt, M; Koch, B P; Schmitt-Kopplin, Ph; Perdue, E M

    2008-12-01

    Soils, sediments, freshwaters, and marine waters contain natural organic matter (NOM), an exceedingly complex mixture of organic compounds that collectively exhibit a nearly continuous range of properties (size-reactivity continuum). NOM is composed mainly of carbon, hydrogen, and oxygen, with minor contributions from heteroatoms such as nitrogen, sulfur, and phosphorus. Suwannee River fulvic acid (SuwFA) is a fraction of NOM that is relatively depleted in heteroatoms. Ultrahigh resolution Fourier transform ion cyclotron (FTICR) mass spectra of SuwFA reveal several thousand molecular formulas, corresponding in turn to several hundred thousand distinct chemical environments of carbon even without accountancy of isomers. The mass difference deltam among adjoining C,H,O-molecules between and within clusters of nominal mass is inversely related to molecular dissimilarity: any decrease of deltam imposes an ever growing mandatory difference in molecular composition. Molecular formulas that are expected for likely biochemical precursor molecules are notably absent from these spectra, indicating that SuwFA is the product of diagenetic reactions that have altered the major components of biomass beyond the point of recognition. The degree of complexity of SuwFA can be brought into sharp focus through comparison with the theoretical limits of chemical complexity, as constrained and quantized by the fundamentals of chemical binding. The theoretical C,H,O-compositional space denotes the isomer-filtered complement of the entire, very vast space of molecular structures composed solely of carbon, hydrogen, and oxygen. The molecular formulas within SuwFA occupy a sizable proportion of the theoretical C,H,O-compositional space. A 100 percent coverage of the theoretically feasible C,H,O-compositional space by SuwFA molecules is attained throughout a sizable range of mass and H/C and O/C elemental ratios. The substantial differences between (and complementarity of) the SuwFA molecular

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. Buried Waste Integrated Demonstration Plan

    Energy Technology Data Exchange (ETDEWEB)

    Kostelnik, K.M.

    1991-12-01

    This document presents the plan of activities for the Buried Waste Integrated Demonstration (BWID) program which supports the environmental restoration (ER) objectives of the Department of Energy (DOE) Complex. Discussed in this plan are the objectives, organization, roles and responsibilities, and the process for implementing and managing BWID. BWID is hosted at the Idaho National Engineering Laboratory (INEL), but involves participants from throughout the DOE Complex, private industry, universities, and the international community. These participants will support, demonstrate, and evaluate a suite of advanced technologies representing a comprehensive remediation system for the effective and efficient remediation of buried waste. The processes for identifying technological needs, screening candidate technologies for applicability and maturity, selecting appropriate technologies for demonstration, field demonstrating, evaluation of results and transferring technologies to environmental restoration programs are also presented. This document further describes the elements of project planning and control that apply to BWID. It addresses the management processes, operating procedures, programmatic and technical objectives, and schedules. Key functions in support of each demonstration such as regulatory coordination, safety analyses, risk evaluations, facility requirements, and data management are presented.

  6. Modeling Soil Organic Matter Dynamics Under Intensive Cropping Systems on the Huang-Huai-Hai Plain of China

    Institute of Scientific and Technical Information of China (English)

    LEI Hong-Jun; LI Bao-Guo; BAI You-Lu; HUANG Yuan-Fang; L(U) Yi-Zhong; LI Gui-Tong

    2006-01-01

    A modified CQESTR model, a simple yet useful model frequently used for estimating carbon sequestration in agricultural soils, was developed and applied to evaluate the effects of intensive cropping on soil organic matter (SOM)dynamics and mineralization as well as to estimate carbon dioxide emission from agricultural soils at seven sites on the Huang-Huai-Hai Plain of China. The model was modified using site-specific parameters from short- and mid-term buried organic material experiments at four stages of biomass decomposition. The predicted SOM results were validated using independent data from seven long-term (10- to 20-year) soil fertility experiments in this region. Regression analysis on1151 pairs of predicted and measured SOM data had an r2 of 0.91 (P ≤ 0.01). Therefore, the modified model was able to predict the mineralization of crop residues, organic amendments, and native SOM. Linear regression also showed that SOM mineralization rate (MR) in the plow layer increased by 0.22% when annual crop yield increased by 1 t ha-1 (P ≤ 0.01),suggesting an improvement in SOM quality. Apparently, not only did the annual soil respiration efflux merely reflect the intensity of soil organism and plant metabolism, but also the SOM MR in the plow layer. These results suggested that the modified model was simple yet valuable in predicting SOM trends at a single agricultural field and could be a powerful tool for estimating C-storage potential and reconstructing C storage on the Huang-Huai-Hai Plain of China.

  7. Organic matter quantity and source affects microbial community structure and function following volcanic eruption on Kasatochi Island, Alaska

    Science.gov (United States)

    Zeglin, Lydia H.; Wang, Bronwen; Waythomas, Christopher F.; Rainey, Frederick; Talbot, Sandra

    2016-01-01

    In August 2008, Kasatochi volcano erupted and buried a small island in pyroclastic deposits and fine ash; since then, microbes, plants and birds have begun to re-colonize the initially sterile surface. Five years post-eruption, bacterial 16S rRNA gene and fungal internal transcribed spacer (ITS) copy numbers and extracellular enzyme activity (EEA) potentials were one to two orders of magnitude greater in pyroclastic materials with organic matter (OM) inputs relative to those without, despite minimal accumulation of OM (plants versus birds as OM input vectors. Although soil pH ranged from 3.9 to 7.0, and %C ranged 100×, differentiation between plant- and bird-associated microbial communities suggested that cell dispersal or nutrient availability are more likely drivers of assembly than pH or OM content. This study exemplifies the complex relationship between microbial cell dispersal, soil geochemistry, and microbial structure and function; and illustrates the potential for soil microbiota to be resilient to disturbance.

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

    Science.gov (United States)

    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.

  9. NITROGEN DEPOSITION AND ORGANIC MATTER MANIPULATIONS AFFECT GROSS AND NET NITROGEN TRANSFORMATIONS IN TWO TEMPERATE FORESTS SOILS

    Science.gov (United States)

    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...

  10. Molecular composition of organic matter controls methylmercury formation in boreal lakes

    Science.gov (United States)

    Bravo, Andrea G.; Bouchet, Sylvain; Tolu, Julie; Björn, Erik; Mateos-Rivera, Alejandro; Bertilsson, Stefan

    2017-02-01

    A detailed understanding of the formation of the potent neurotoxic methylmercury is needed to explain the large observed variability in methylmercury levels in aquatic systems. While it is known that organic matter interacts strongly with mercury, the role of organic matter composition in the formation of methylmercury in aquatic systems remains poorly understood. Here we show that phytoplankton-derived organic compounds enhance mercury methylation rates in boreal lake sediments through an overall increase of bacterial activity. Accordingly, in situ mercury methylation defines methylmercury levels in lake sediments strongly influenced by planktonic blooms. In contrast, sediments dominated by terrigenous organic matter inputs have far lower methylation rates but higher concentrations of methylmercury, suggesting that methylmercury was formed in the catchment and imported into lakes. Our findings demonstrate that the origin and molecular composition of organic matter are critical parameters to understand and predict methylmercury formation and accumulation in boreal lake sediments.

  11. Sustainable Water Supplies:Reducing The Organic Matter Content of Potable Water

    Science.gov (United States)

    Sohn, Mary

    2009-07-01

    As freshwater becomes a limiting factor in sustainable development, water treatment processes which can efficiently oxidize both anthropogenic and natural sources of organic matter are becoming crucial. While many anthropogenic organic compounds found in freshwater pose a direct risk to human health, natural organic matter such as humic acids, pose an indirect risk through the production of disinfection byproducts resulting from chlorination. Removal of dissolved natural organic matter before disinfection of potable water is recommended for the production of potable water in water treatment facilities. Several promising developments in dissolved organic matter oxidation are described including hydroxyl radical, advanced oxidation processes and ferrate (VI). The feasibility of applying these processes to water treatment on a large scale is largely dependent on cost.

  12. Effect of organic matter amendment, arsenic amendment and water management regime on rice grain arsenic species.

    Science.gov (United States)

    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.

  13. Thermophilic anaerobes in arctic marine sediments induced to mineralize complex organic matter at high temperature

    DEFF Research Database (Denmark)

    Hubert, Casey; Arnosti, Carol; Brüchert, Volker

    2010-01-01

    , as well as with the addition of freeze-dried Spirulina or individual high-molecular-weight polysaccharides. During 50°C incubation experiments, Arctic thermophiles catalysed extensive mineralization of the organic matter via extracellular enzymatic hydrolysis, fermentation and sulfate reduction. This high...... temperature-induced food chain mirrors sediment microbial processes occurring at cold in situ temperatures (near 0°C), yet it is catalysed by a completely different set of microorganisms. Using sulfate reduction rates (SRR) as a proxy for organic matter mineralization showed that differences in organic matter...

  14. Challenges in modelling dissolved organic matter dynamics in agricultural soil using DAISY

    DEFF Research Database (Denmark)

    Gjettermann, Birgitte; Styczen, Merete; Hansen, Hans Christian Bruun

    2008-01-01

    Because dissolved organic matter (DOM) plays an important role is terrestrial C-, N- and P-balances and transport of these three components to aquatic environments, there is a need to include it in models. This paper presents the concept of the newly developed DOM modules implemented in the DAISY...... pedotransfer functions taking into account the soil content of organic matter, Al and Fe oxides. The turnover of several organic matter pools including one DOM pool are described by first-order kinetics. The DOM module was tested at field scale for three soil treatments applied after cultivating grass...

  15. Optimizing Hollow Fibre Nanofiltration for Organic Matter Rich Lake Water

    Directory of Open Access Journals (Sweden)

    Alexander Keucken

    2016-09-01

    Full Text Available Over the years, various technologies have been utilized for Natural Organic Matter (NOM removal with varying degrees of success. Conventional treatment methods comprising of coagulation, flocculation, sedimentation, or filtration are widely used to remove NOM. An alternative to these conventional methods is to use spiral wound membranes. These membranes tend to remove too much hardness whilst being ineffective in disinfection. They also have a low tolerance to chlorine and thus, have limited chemical cleaning options. In this study, we investigated how an alternative and new innovative filtration concept, based on capillary NF membranes from modified polyethersulfone (PES, may be used to treat soft but humus-rich surface waters. Comprehensive performance tests, with a fully automated membrane pilot equipped with a full-scale sized test module (40 m2 membrane surface, were conducted at WTP Görvälnverket, which is operated by the water utility Norrvatten, providing drinking water from Mälaren (SUVA = 2.7–3.3, TOC = 7.0–10.0 mg·L−1 for about 500,000 people in the northern part of the Swedish capital of Stockholm. The removal of both UV and DOC was modeled using a solution diffusion approach. The optimized parameters allow deducing optimal operation conditions with respect to energy, water consumption, and permeate water quality. Optimal cross flow velocity was determined to be 0.75 m·s−1 at 80% recovery and a flux of 12–18 L·m−2·h−1. Under these conditions, 80% of the UV, 75% of the Humic Substances (MW = 600 and 70% of TOC were removed (from 8 to below 2 mg·L−1. A higher cross flow velocity led to marginal improvement (+2% while both higher and lower membrane fluxes degraded permeate water quality. Apparent optimized diffusion coefficients for UV and TOC were around 1.2–2.4 × 10−10·m2·s−1 and were similar to values found in the literature. Due to their higher diffusion coefficients and higher permeability

  16. Analytical Determinations of the Phenolic Content of Dissolved Organic Matter

    Science.gov (United States)

    Pagano, T.; Kenny, J. E.

    2010-12-01

    Indicators suggest that the amount of dissolved organic matter (DOM) in natural waters is increasing. Climate Change has been proposed as a potential contributor to the trend, and under this mechanism, the phenolic content of DOM may also be increasing. We have explored the possibility of assessing the phenolic character of DOM using fluorescence spectroscopy as a more convenient alternative to wet chemistry methods. In this work, parallel factor analysis (PARAFAC) was applied to fluorescence excitation emission matrices (EEMs) of humic samples in an attempt to analyze their phenolic content. The PARAFAC results were correlated with phenol concentrations derived from the Folin-Ciocalteau reagent-based method. The reagent-based method showed that the phenolic content of five International Humic Substance Society (IHSS) DOM samples vary from approximately 5 to 22 ppm Tannic Acid Equivalents (TAE) in phenol concentration. A five-component PARAFAC fit was applied to the EEMs of the IHSS sample dataset and it was determined by PARAFAC score correlations with phenol concentrations from the reagent-based method that components C1 (R2=0.78), C4 (R2=0.82), and C5 (R2=0.88) have the highest probability of containing phenolic groups. Furthermore, when the scores of components C4 and C5 were summed, the correlation improved (R2=0.99). Likewise, when the scores of C1, C4, and C5 were summed, their correlations were stronger than their individual parts (R2=0.89). Since the reagent-based method is providing an indicator of “total phenol” amount, regardless of the exact molecular structure of C1, C4, and C5, it seems reasonable that each of these components individually contributes a portion to the summed “total phenol” profile, and that the sum of their phenol-related spectral parts represents a larger portion of the “total phenol” index. However, when the sum of all five components were plotted against the reagent-based phenol concentrations, due to the considerable

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

    Science.gov (United States)

    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

    2016-10-01

    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.

  18. Effect of oxygen on the degradability of organic matter in subtidal and intertidal sediments of the North Sea area

    NARCIS (Netherlands)

    Dauwe, B.; Middelburg, J.J.; Herman, P.M.J.

    2001-01-01

    The effect of oxygen on the degradation of sedimentary organic matter has been determined for 6 subtidal stations and 3 intertidal stations in the North Sea area. The stations were selected to cover a range of organic matter lability and sediment texture (and hence concentrations of organic matter).

  19. Process data descriptions for the production of synthetic organic materials : input data for the MATTER study

    NARCIS (Netherlands)

    Joosten, L.A.J.

    1998-01-01

    This report describes technologies for the production of synthetic organic materials. It is a result of the MATTER study (MATerials Technologies for CO2 Emission Reduction). The MATTER study focuses on reduction of CO2 emissions caused by the use of energy and materials. This report aims at providin

  20. Process data descriptions for the production of synthetic organic materials : input data for the MATTER study

    NARCIS (Netherlands)

    Joosten, L.A.J.

    This report describes technologies for the production of synthetic organic materials. It is a result of the MATTER study (MATerials Technologies for CO2 Emission Reduction). The MATTER study focuses on reduction of CO2 emissions caused by the use of energy and materials. This report aims at

  1. MONITORING OF ORGANIC POLLUTION AND MATURITY OF ORGANIC MATTER FROM SLUDGE LANDFILLING

    Directory of Open Access Journals (Sweden)

    SLIMANE LAHSAINI

    2016-07-01

    Full Text Available The biotransformation during the 3 years of sludge landfilling was evaluated by physicochemical analysis and phytotoxicity test. The final product exhibited a high degree of decomposition rate (51.06 % than the controls as shown by a decrease of C/N ratio of about 19.67. The results showed that the lipid, surfactant and polyphenol as main compound of the sludge were breakdown over time. The concentrations decreased from 29.9 to 11.8 mg·g-1 and 3.4 to 0.6 mg·g-1, respectively for surfactant and polyphenols after 3 years of landfilling. This corresponds to a reduction of 80.2 % for polyphenols and 60.4 % for surfactant, due to the microorganisms activity. Total lipids decrease from 16.5 to 6.27 mg·g-1 of dry matter, representing an abatement rate of about 62 %. The evolution of organic matter reflects the progress of the humification process, which judging by the increase in the polymerization degree, is about 20 %. The landfilling efficiency to reduce phytotoxicity of sludge was confirmed by the germination index, which reached 52 and 59 %, respectively for alfalfa and cress after 3 years of landfilling. These results are promising and pave the way for agricultural spreading of sludge.

  2. Effects of polar and nonpolar groups on the solubility of organic compounds in soil organic matter

    Science.gov (United States)

    Chiou, C.T.; Kile, D.E.

    1994-01-01

    Vapor sorption capacities on a high-organic-content peat, a model for soil organic matter (SOM), were determined at room temperature for the following liquids: n-hexane, 1,4-dioxane, nitroethane, acetone, acetonitrile, 1-propanol, ethanol, and methanol. The linear organic vapor sorption is in keeping with the dominance of vapor partition in peat SOM. These data and similar results of carbon tetrachloride (CT), trichloroethylene (TCE), benzene, ethylene glycol monoethyl ether (EGME), and water on the same peat from earlier studies are used to evaluate the effect of polarity on the vapor partition in SOM. The extrapolated liquid solubility from the vapor isotherm increases sharply from 3-6 wt % for low-polarity liquids (hexane, CT, and benzene) to 62 wt % for polar methanol and correlates positively with the liquid's component solubility parameters for polar interaction (??P) and hydrogen bonding (??h). The same polarity effect may be expected to influence the relative solubilities of a variety of contaminants in SOM and, therefore, the relative deviations between the SOM-water partition coefficients (Kom) and corresponding octanol-water partition coefficients (Kow) for different classes of compounds. The large solubility disparity in SOM between polar and nonpolar solutes suggests that the accurate prediction of Kom from Kow or Sw (solute water solubility) would be limited to compounds of similar polarity.

  3. Heterogeneity of the organic matter in the Guayuta group, Eastern Venezuelan Basin

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, M.; Gallango, O.; Ruggiero, A.; Jordan, N. (Intevep, S.A., Caracas (Venezuela)); Lefargue, E. (I.F.P., Rueil Malmaison (France))

    1993-02-01

    The purpose of this study is to evaluate the organic matter heterogeneities in the Guayuta Group as a principal hydrocarbon source rock in the Eastern Venezuelan Basin. In order to do this, thirteen wells and five work stations on outcrops of the Interior Mountain Belt were analyzed to study the regional and vertical variations in the geochemical characteristics of the organic matter. It is possible to detect significant differences in quality and quantity of the organic matter which could corroborate the regional development of two organic facies from North to South in the Maturin Subbasin. The northern organic facies show excellent characteristics as source rock. The study of vertical distribution of organic matter was carried out in a well of northern part of the Monagas state, which represents the southern organic facies. It shows an irregular input of continental organic matter, thermally immature. Besides the organic matter content was low (around 1.5%) without depth tendencies. These sediments are clastic and bioclastic in contrast with carbonates and pelagic shales of the Guayuta Group in the Interior Mountain Belt. The outcrop samples studied show a high total organic content (2-6%) despite the high maturity determined on kerogen. The systematic study of this geochemical parameter show pseudocyclic relationships with a general tendency to increase toward the bottom of the section. V, Ni, and S determinations could indicate that anoxic conditions were developing toward the North where the marine organic matter was sedimenting. The results of this study are in agreement with paleogeographic model of sedimentation during middle and late Cretaceous, with sources of sediments from South and a progressive depth of the basin toward the North.

  4. Variation of reactivity of particulate and sedimentary organic matter along the Zhujiang River Estuary

    Institute of Scientific and Technical Information of China (English)

    Chen Jianfang; Jin Haiyan; Yin Kedong; Li Yan

    2003-01-01

    To investigate organic matter source and reactivity in the Zhujiang River (Pearl River)Estuary and its adjacent areas, particulate organic carbon (POC), particulate hydrolysable amino acids (PHAA), and Chl a during two cruises in July 1999 and July 2000 were measured. The highest POC and PHAA concentration was observed in the waters with maximum Chl a. The spectra distribution,relative content (dry weight in milligram per gram), PHAA-C% POC and other indicators such as the ratios of amino acids vs. amino sugars (AA/AS) and glucosamine vs. galactosamine (Glum/Gal) suggested that particulate amino acids in the water column and sediments in the Zhujiang River Estuary were mainly derived from biogenic processes rather than transported from terrestrial erosion. In inner estuary where high turbidity was often observable, organic matter was mainly contributed by re-suspension of bottom sediments with revealed zooplankton, microbial reworked characteristics, which suggest that these organic matters were relatively "old". In the estuarine brackish region, organic matter in water column is mainly contributed by relatively fresh, easily degradable phytoplankton derived organic matter.During physical - biological processes within the eastuary, organic matter derived from phytoplankton was subjected to alteration by zooplankton grazing and bacterial reworking.

  5. Management of organic matter in the tropics: Translating theory into practice

    NARCIS (Netherlands)

    Palm, C.A.; Giller, K.E.; Mafongoya, P.L.; Swift, M.J.

    2001-01-01

    Inputs of organic materials play a central role in the productivity of many tropical farming systems by providing nutrients through decomposition and substrate for synthesis of soil organic matter (SOM). The organic inputs in many tropical farming systems such as crop residues, manures, and natural

  6. Long-term changes in organic matter of woodland soils cleared for arable cropping in Zimbabwe

    NARCIS (Netherlands)

    Zingore, S.; Manyame, C.; Nyamugafata, P.; Giller, K.E.

    2005-01-01

    Subsistence farmers in Africa depend largely on the soil organic matter to sustain crop productivity. Long-term changes in soil organic carbon and nitrogen were measured after woodland clearance for smallholder subsistence farming or for commercial farming. The contents of organic carbon and nitroge

  7. Long-term changes in organic matter of woodland soils cleared for arable cropping in Zimbabwe

    NARCIS (Netherlands)

    Zingore, S.; Manyame, C.; Nyamugafata, P.; Giller, K.E.

    2005-01-01

    Subsistence farmers in Africa depend largely on the soil organic matter to sustain crop productivity. Long-term changes in soil organic carbon and nitrogen were measured after woodland clearance for smallholder subsistence farming or for commercial farming. The contents of organic carbon and nitroge

  8. Lyophilization, Reconstitution, and DBP Formation in Reverse-Osmosis Concentrated Natural Organic Matter

    Science.gov (United States)

    Drinking water treatment and disinfection byproduct (DBP) research can be complicated by natural organic matter (NOM) temporal variability. NOM preservation by lyophilization (freeze-drying) has been long practiced to address this issue; however, its applicability for drinking w...

  9. Innovative process scheme for removal of organic matter, phosphorus and nitrogen from pig manure

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Schmidt, Jens Ejbye; Angelidaki, Irini

    2008-01-01

    Disposal of pig manure often requires treatment with respect to environmental legislations. In this study different processes for reduction of the organic matter (anaerobic digestion, effluent separation by decanter centrifugation, membrane microfiltration, post-digestion in upflow anaerobic sludge...

  10. Phosphate, carbonate and organic matter distribution in sediment cores off Bombay-Saurashtra coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Rao, Ch.M.

    Phosphate, organic matter and calcium carbonate content in five sediment cores (three from the outer shelf one from the slope and one from the basin) from the Arabian Sea have been determined. The distribution pattern indicates their close genetic...

  11. Intercropping affects the rate of decomposition of soil organic matter and root litter

    NARCIS (Netherlands)

    Cong, W.; Hoffland, E.; Li, L.; Janssen, B.H.; Werf, van der W.

    2015-01-01

    Aims - Intercropping increases aboveground and belowground crop productivity, suggesting potential for carbon sequestration. Here we determined whether intercropping affects decomposition of soil organic matter (SOM) and root litter. Methods - We measured in the laboratory and the field the

  12. Distribution and sources of organic matter in surface sediments of the eastern continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, M.S.; Naidu, S.A.; Subbaiah, Ch.V.; Sarma, V.V.S.S.; Reddy, N.P.C.

    The sources and distribution of organic matter (OM) in surface sediments of the eastern continental margin of India, including the region influenced by river discharge, were investigated using content, molar C:N ratios and stable isotopes of carbon...

  13. Lyophilization, Reconstitution, and DBP Formation in Reverse-Osmosis Concentrated Natural Organic Matter

    Science.gov (United States)

    Drinking water treatment and disinfection byproduct (DBP) research can be complicated by natural organic matter (NOM) temporal variability. NOM preservation by lyophilization (freeze-drying) has been long practiced to address this issue; however, its applicability for drinking w...

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

    Science.gov (United States)

    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 (pH 6.0. Possible mechanisms of dissolution include surface complexation of mercury and oxidation of surface sulfur species by the organic matter.

  15. Microphytobenthos and benthic macroalgae determine sediment organic matter composition in shallow photic sediments

    NARCIS (Netherlands)

    Hardison, A.K.; Canuel, E.A/; Anderson, I.C.; Tobias, C.R.; Veuger, B.; Waters, M.N.

    2013-01-01

    Microphytobenthos and benthic macroalgae play an important role in system metabolism within shallow coastal bays. However, their independent and interactive influences on sediment organic matter (SOM) are not well understood. We investigated the influence of macroalgae and microphytobenthos on SOM

  16. Organic-matter maturation and petroleum generation model in the Yinggehai and Qiongdongnan basins

    Institute of Scientific and Technical Information of China (English)

    郝芳; 李思田; 孙永传; 张启明

    1996-01-01

    The enhancement of organic-matter maturation and petroleum generation by the migration and accumulation of active hydrothermal fluids in the high thermal-gradient, strongly overpressured environments in the Yinggehai and Qiongdongnan basins is systematically demonstrated by combination of geological, geochemical analysis and basin modeling. The retardation of organic-matter thermal evolution by abnormal pore-pressure is recognized, its manifestation and dynamic mechanism are illustrated, and chemical kinetic modeling of the pressure retardation is carried out. On this basis, the model of organic-matter thermal evolution and petroleum generation in high thermal-gradient, strongly overpressured environments is summarized. A correct understanding of the effects of active hydrothermal fluids and abnormal pore-fluid pressures on organic-matter thermal evolution is of great theoretical and practical significance for thermal history analysis, basin modeling and petroleum resource evaluation.

  17. Photobleaching Kinetics of Chromophoric Dissolved Organic Matter Derived from Mangrove Leaf Litter and Floating Sargassum Colonies

    Science.gov (United States)

    We examined the photoreactivity of chromophoric dissolved organic matter (CDOM) derived from Rhizophora mangle (red mangrove) leaf litter and floating Sargassum colonies as these marine plants can be important contributors to coastal and open ocean CDOM pools, respectively. Mangr...

  18. Intercropping affects the rate of decomposition of soil organic matter and root litter

    NARCIS (Netherlands)

    Cong, W.; Hoffland, E.; Li, L.; Janssen, B.H.; Werf, van der W.

    2015-01-01

    Aims - Intercropping increases aboveground and belowground crop productivity, suggesting potential for carbon sequestration. Here we determined whether intercropping affects decomposition of soil organic matter (SOM) and root litter. Methods - We measured in the laboratory and the field the breakdow

  19. Pathways of anaerobic organic matter decomposition in tundra soils from Barrow, Alaska

    National Research Council Canada - National Science Library

    Herndon, Elizabeth M; Mann, Benjamin F; Roy Chowdhury, Taniya; Yang, Ziming; Wullschleger, Stan D; Graham, David; Liang, Liyuan; Gu, Baohua

    2015-01-01

    .... To predict releases of CO 2 and CH 4 from tundra soils, it is necessary to identify pathways of soil organic matter decomposition under the anoxic conditions that are prevalent in Arctic ecosystem...

  20. Biodestructive processes occurring in the organic matter of lowland peat in the arctic zone

    Science.gov (United States)

    Svarovskaya, L. I.; Altunina, L. K.; Serebrennikova, O. V.

    2016-11-01

    A model experiment was carried on in laboratory conditions. The biodestruction of organic matter was studied using lowland peat samples collected in Kolguev Island in Barents Sea. Here the purpose was to obtain information about the species range and the activity of bacterial complex involved in the destruction processes of lowland peat organic matter from the natural environment by simulating the Arctic zone climate. The species range is found to include bacteria dominant species, i.e. Rhodococcus, Arthrobacter, Bacillus and Pseudomonas. In order to stimulate the biodestruction of organic matter, inoculate was added to the culture medium containing peat; its composition and dose were determined by the trial-and-error method. The catalytic activity of bacterial ferments was initiated in the presence of inoculate; hence, the desired effect was achieved. The composition of the organic matter of bacterial biomass and peat was analyzed by the method of gas chromatography-mass spectrometry.

  1. Carbon Turnover in Alaskan Tundra Soils: Effects of Organic Matter Quality, Temperature, Moisture and Fertilizer

    National Research Council Canada - National Science Library

    Gaius R. Shaver; A. E. Giblin; K. J. Nadelhoffer; K. K. Thieler; M. R. Downs; J. A. Laundre; E. B. Rastetter

    2006-01-01

    .... This study describes how soil C loss is related to temperature, moisture and chemical composition of organic matter in Alaskan tundra soils, including soils that were fertilized annually for 8 years prior to the study...

  2. Hyperspectral analysis of soil nitrogen, carbon, carbonate, and organic matter using regression trees.

    Science.gov (United States)

    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 R(2) 0.91 (p organic matter R(2) 0.98 (p organic matter for upper soil horizons in a nondestructive method.

  3. Sorption of Enrofloxacin and Ciprofloxacin in Agricultural Soils: Effect of Organic Matter

    National Research Council Canada - National Science Library

    Teixidó, Marc; Medeiros, Joana; Beltrán, José L; Prat, Maria-Dolors; Granados, Mercè

    2014-01-01

    ...), an organic matter (OM) surrogate, to the sorption of FQs in natural soils. Sorption of enrofloxacin and ciprofloxacin was studied in two completely different Spanish agricultural soils with similar pH...

  4. Fluorescence characteristic changes of dissolved organic matter during municipal solid waste composting

    Institute of Scientific and Technical Information of China (English)

    WEI Zi-min; XI Bei-dou; WANG Shi-ping; XU Jing-gang; ZHOU Yu-yan; LIU Hong-liang

    2005-01-01

    Dissolved organic matter(DOM) of municipal solid waste(MSW) consists of minerals, water, ash and humic substances, and is known to enhance plant growth. In this study, inoculating microbes (Z J, MS) were used in municipal solid wastes composting, and composting implemented a industrialized technology. During composting, dissolved organic matter was extracted from the compost and purified. The spectral characteristics of dissolved organic matter was determined by fluorescence emission, excitation, and synchronous spectroscopy. Fluorescence emission, excitation, and synchronous spectra characterized by different relative fluorescent intensities and peaks over time. Fluorescence spectra were similar to that of fulvic acid in sewage sludge, indicating the presence of dissolved organic matter with aromatic structures and a high degree of molecular polymerization. Compared with the controls with no microbial inoculation,the microbe-inoculated treatments exhibited the increase of aromatic polycondensation, in the following order: MS + ZJ > ZJ > MS >CK.

  5. Role of iron deficiency in production and remineralization of organic matter in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    concentrations of macronutrients, especially nitrate and phosphate are rapidly transported by filaments and plumes over 1,000 km offshore Export of particulate organic matter (POM) produced by the resultant phytoplankton blooms and its remineralization below...

  6. [Spatial heterogeneity of soil organic matter and its response to disturbance in karst peak cluster depressions].

    Science.gov (United States)

    Ouyang, Zi-Wen; Peng, Wan-Xia; Song, Tong-Qing; Zeng, Fu-Ping; Wang, Ke-Lin; Guan, Xin; Wu, Hai-Yong

    2009-06-01

    By using geostatistic methods, this paper studied the spatial variation and distribution of soil organic matter as well as its ecological processes and related mechanisms in four typical disturbed areas (cropland, man-made forest, secondary forest, and primary forest) of karst peak cluster depressions in northwest Guangxi of China. Eighty soil samples (0-20 cm) were collected from an aligned grid of 10 m x 10 m for the analysis of soil organic matter. The soil organic matter content increased significantly (P disturbance and the vegetation succession from crop to man-made forest to secondary forest to primary forest. Soil organic matter content had good spatial autocorrelation in all of the four typical disturbed areas, but its spatial heterogeneity differed. Gaussian model fitted best to the semivariance functions of soil organic matter content in the study areas except secondary forest area where exponential model fitted well. In cropland area, the spatial autocorrelation of soil organic matter was at medium level, with the C0/(C0 + C) being 26.5%; while in the other three areas, the spatial autocorrelation was at high level, with the C0/(C0 + C) being 9.0%-22.6%. The range and scale of the spatial autocorrelation of soil organic matter in cropland and man-made forest areas were larger than those in the other two areas, possibly due to the strong human disturbance and the homogeneity of low energy. The range of the spatial autocorrelation of soil organic matter in primary forest area was large due to the high vegetation coverage, while that in secondary forest area was the lowest due to the diverse vegetation communities and their uneven distribution. The low fractal value (D) of semivariance functions of soil organic matter in man-made forest and primary forest areas suggested that a strong spatial dependence existed, while the high D in cropland and secondary forest areas suggested a great random variance of spatial distribution of soil organic matter occurred

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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 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)). 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 environmental conditions.

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

    Science.gov (United States)

    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.

  10. Influence of organic matters on AsIII oxidation by the microflora of polluted soils.

    Science.gov (United States)

    Lescure, T; Moreau, J; Charles, C; Ben Ali Saanda, T; Thouin, H; Pillas, N; Bauda, P; Lamy, I; Battaglia-Brunet, F

    2016-06-01

    The global AsIII-oxidizing activity of microorganisms in eight surface soils from polluted sites was quantified with and without addition of organic substrates. The organic substances provided differed by their nature: either yeast extract, commonly used in microbiological culture media, or a synthetic mixture of defined organic matters (SMOM) presenting some common features with natural soil organic matter. Correlations were sought between soil characteristics and both the AsIII-oxidizing rate constants and their evolution in accordance with inputs of organic substrates. In the absence of added substrate, the global AsIII oxidation rate constant correlated positively with the concentration of intrinsic organic matter in the soil, suggesting that AsIII-oxidizing activity was limited by organic substrate availability in nutrient-poor soils. This limitation was, however, removed by 0.08 g/L of added organic carbon. In most conditions, the AsIII oxidation rate constant decreased as organic carbon input increased from 0.08 to 0.4 g/L. Incubations of polluted soils in aerobic conditions, amended or not with SMOM, resulted in short-term As mobilization in the presence of SMOM and active microorganisms. In contrast, microbial AsIII oxidation seemed to stabilize As when no organic substrate was added. Results suggest that microbial speciation of arsenic driven by nature and concentration of organic matter exerts a major influence on the fate of this toxic element in surface soils.

  11. Reading the molecular signature of ecosystems in dissolved organic matter

    Science.gov (United States)

    Simon, Carsten; Roth, Vanessa-Nina; Dittmar, Thorsten; Gleixner, Gerd

    2017-04-01

    To make forecasts about the behavior, origin and fate of dissolved organic matter (DOM) in the environment, we need further insights into the molecular composition of this complex mixture. The development of soft ionization procedures and mass spectrometers capable of ultrahigh resolution (Fourier-Transform Mass Spectrometry, FTMS) have opened important new horizons in this regard. However, the application of such systems is restricted due to high purchase and maintenance costs. The introduction of the improved version of the Orbitrap FTMS analyzer ("Elite") in 2011 could open new perspectives for the molecular-level investigation of DOM, as it combines high performance with lower overall costs. We compared the Orbitrap with an established FT-ICR-MS (ion cyclotron resonance, 15 Tesla) to assess the potential of this analyzer on a broad set of 17 terrestrial and aquatic DOM samples prepared by solid phase extraction (SPE-DOM, Dittmar et al. 2008). The dataset included groundwater, soil water from different depths and vegetation covers (forests, grassland), as well as bog, river, lake and marine waters. We here show that the Orbitrap analyzer is able to detect hard-to-resolve nitrogen and sulfur containing compounds (triplet signal [CHO]N2O2, [CHO]C5, [CHO]C2H4S) up to a mass-to-charge ratio of 430 and well retrieves the intensity information of the FT-ICR-MS. Both points have been recently reported as major obstacles in the detailed molecular-level analyses of DOM by Orbitrap systems (Hawkes et al. 2016). In our data, slight deviations in intensity representation were only found in samples characterized by stronger aromaticity, and especially in the lower mass range (below m/z 250). A subset of > 6000 formulae detected in both sets was used to further characterize the sample set on a molecular level. The derived ecological information, as assessed by ordination and post-ordination gradient fitting, was highly consistent among both datasets. A dominating first

  12. Tracing organic matter sources and carbon burial in mangrove sediments over the past 160 years

    Science.gov (United States)

    Gonneea, Meagan Eagle; Paytan, Adina; Herrera-Silveira, Jorge A.

    2004-10-01

    Mangrove ecosystems may be a source of organic carbon and nutrients to adjacent coastal systems on one hand and provide a sedimentary sink for organic carbon on the other. The balance between these two functions may be sensitive to both natural and anthropogenically induced variability, yet these effects have not been thoroughly evaluated in mangrove ecosystems. We determine organic matter sources and carbon burial rates over the past 160 years in three lagoons on the Yucatan Peninsula, Mexico. Carbon isotopes and C/N elemental ratios are utilized to trace the three sources contributing to sedimentary organic matter, mangroves, seagrasses and phytoplankton, while nitrogen isotopes are used to elucidate potential post-depositional biogeochemical transformations in mangrove lagoon sediments. All three organic matter sources contribute to organic carbon burial. Phytoplankton and mangroves are the dominant sources of organic matter in lagoon bank sediments and seagrasses are a significant source to central lagoon sediments. Organic carbon burial rates are higher at the lagoon fringes, where mangrove vegetation dominates, than in seagrass-dominated mid-lagoon areas. A reduction in mangrove contribution to the sedimentary organic matter pool concurrent with reduced total organic carbon burial rates is observed in the recent past at all three lagoons studied. Natural cycles in sediment organic matter source over the past 160 years are observed in a high-resolution core. These fluctuations correspond to climatic variability in this region, as recorded in deep-sea foraminiferal assemblages. Additional work is required in order to differentiate between recent anthropogenic perturbations and natural variability in organic carbon sources and burial rates within these ecosystems.

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

    Science.gov (United States)

    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 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 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.

  14. Application of hybrid coagulation microfiltration with air backflushing to direct sewage concentration for organic matter recovery.

    Science.gov (United States)

    Jin, Zhengyu; Gong, Hui; Wang, Kaijun

    2015-01-01

    The idea of sewage concentration is gradually being accepted as a promising and sustainable way of wastewater resource recovery. In this study, Hybrid coagulation microfiltration (HCM) with air backflushing (AB) was investigated to effectively concentrate organic matter. Compared to direct sewage microfiltration, the addition of coagulation process improved the filtration performance with less fouling trends and better concentration efficiency. The use of AB exhibited even better performance within the same 7-h preliminary concentration period by reducing to one tenth of the resistance and collecting around four times as much organic matter into the product concentrate as in direct sewage microfiltration. During 93-h lab-scale continuous concentration by HCM with AB, a product concentrate with the COD concentration over 15,000 mg/L was achieved and around 70% of total influent organic matter could be recovered. Compared to Direct Membrane Filtration (DMF) with Chemically Enhanced Backwash (CEB), HCM with AB achieved better concentration efficiency with higher concentration extent and concentration velocity along with less organic matter mineralization and the more concentrated product despite with lower organic matter retention. HCM with AB could be a promising effective sewage organic matter concentration for resource recovery under optimization.

  15. Photochemical production of hydrogen peroxide from natural algicides: decomposition organic matter from straw.

    Science.gov (United States)

    Ma, Hua; Zhang, Jie; Tong, Liyin; Yang, Jixiang

    2015-08-01

    The ability of decomposition organic matter from three natural algicides (barley, rice, and wheat straw) and natural organic matter (NOM) isolates to generate hydrogen peroxide under simulated solar irradiation was evaluated in order to understand the mechanism of indirect algae inhibition through a photochemical pathway. Specific optical properties (higher phenolic hydroxyl group contents and lower E2/E3) of barley straw organic matter (BSOM) reveal its outstanding ability to produce H2O2 as a photosensitizer. The appearance of a protein-like structure in BSOM indicated that bacteria or fungi probably transformed the structure of BSOM and brought other organic matter, which may account for its distinct optical properties. The ΦH2O2 of BSOM obtained through aerobic decomposition is 14.73 × 10(-5), which is three times the value of SRHA, whereas the ΦH2O2 value of BSOM obtained for non-aerobic decomposition was 5.30 × 10(-5), still higher than that of SRHA. The ΦH2O2 of rice straw organic matter was slightly lower than those of SRHA and SRFA, but much higher than that of wheat straw organic matter. The superior ability of BSOM to generate H2O2 was partly responsible for the outstanding potential and prior choice of barley straw for cyanobacteria or algae inhibition in various plant decomposition products.

  16. Role of Organic Matter in Formation and Stability of Aggregates in Mulberry Plantation Soils

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The role of organic matter in the formation and stability of soil aggregates in mulberry plantation in the Hang-Jia-Hu Plain,northern Zhejiang Province,was evaluated in this study.A positive correlation was found between water-stable aggregate contents and organic matter contents in the mulberry plantation soils,which supported the hypothesis that organic matter was the main cementing agent in formation of aggregates.A close correlation was also found between stability of aggregate and organic matter contents.Regression analysis showed that total nitrogen content was also an indicator of water-stable aggregate content and stability.The aggregate size distribution indicated that the water-stable aggregates 1~0.25 mm in diameter were the major component of the aggregates in the mulberry plantation soils.The organic matter contents of aggregates ranging from 5 to 0.25 mm in diameter increased with the decrease of aggregate sizes,and the aggregates 1~0.25 mm in diameter had the maximum organic matter content.

  17. Chemical-Structural Changes of Organic Matter in a Semi-Arid Soil After Organic Amendment

    Institute of Scientific and Technical Information of China (English)

    C.NICOL(A)S; G.MASCIANDARO; T.HERN(A)NDEZ; C.GARCIA

    2012-01-01

    A 9-month incubation experiment using composted and non-composted amendments derived from vine pruning waste and sewage sludge was carried out to study the effects of the nature and stability of organic amendments on the structural composition of organic matter (OM) in a semi-arid soil. The changes of soil OM,both in the whole soil and in the extractable carbon with pyrophosphate,were evaluated by pyrolysis-gas chromatography and chemical analyses.By the end of the experiment,the soils amended with pruning waste exhibited less organic carbon loss than those receiving sewage sludge.The non-composted residues increased the aliphatic-pyrolytic products of the OM,both in the whole soil and also in the pyrophosphate extract,with the products derived from peptides and proteins being significantly higher.After 9 months,in the soils amended with pruning waste the relative abundance of phenolic-pyrolytic products derived from phenolic compounds,lignin and proteins in the whole soil tended to increase more than those in the soils amended with sewage sludge.However,the extractable OM with pyrophosphate in the soils amended with composted residues tended to have higher contents of these phenolic-pyrolytic products than that in non-composted ones.Thus,despite the stability of pruning waste,the composting of this material promoted the incorporation of phenolic compounds to the soil OM.The pyrolytic indices (furfural/pyrrole and aliphatic/aromatic ratios) showed the diminution of aliphatic compounds and the increase of aromatic compounds,indicating the stabilization of the OM in the amended soils after 9 months.In conclusion,the changes of soil OM depend on the nature and stability of the organic amendments,with composted vine pruning waste favouring humification.

  18. Towards the Quantification of Organic Matter Degradation in the Deep Biosphere

    Science.gov (United States)

    Larowe, D.; Amend, J. P.

    2011-12-01

    The oxidative degradation of organic matter is a key process in the biogeochemical functioning of the earth system. Quantitative models of organic matter degradation are therefore essential for understanding the chemical state and evolution of the Earth's near-surface environment. In order for these models to capture large-scale patterns of change, the underlying formulations in them must account for organic matter transformations throughout a range of environments characterized by differing temperatures, pressures and compositions over short and long time scales. However, the complex nature of biologically produced organic matter, and it's evolution in the deep biosphere, represent a major obstacle to the development of such models. Here, a new energetic description of organic matter is combined with bioenergetic theory to rationalize observed patterns in the decomposition of natural organic matter by comparing the energetics of the oxidative degradation of a large number of naturally occurring organic compounds. By relating the Gibbs energies of half reactions describing the complete mineralization of the compounds to their average nominal carbon oxidation state, it becomes possible to estimate the energetic potential of the compounds based on major element (C, H, N, O, P, S) ratios. Furthermore, a new thermodynamic limiting function is introduced that can be used to model microbial metabolism throughout the range of conditions in which they are known to be active. This formulation is based upon a comparison of the amount of energy available from any redox reaction to the energy required to a maintain membrane potential, a proxy for the minimum amount of energy a microbe requires in order to be considered active. This function does not require species- or metabolism-specific parameters, and can be used to model metabolisms that capture any amount of energy. The proposed approaches open the way for the inclusion of the thermodynamic properties of organic compounds

  19. Native soil organic matter conditions the response of microbial communities to organic inputs with different stability

    Science.gov (United States)

    Yanardaǧ, Ibrahim H.; Zornoza, Raúl; Bastida, Felipe; Büyükkiliç-Yanardaǧ, Asuman; Acosta, Jose A.; García, Carlos; Faz, Ángel; Mermut, Ahmet R.

    2017-04-01

    The response of soil microbial communities from soils with different soil organic matter (SOM) content to organic inputs with different stability is still poorly understood. Thus, an incubation experiment was designed to study how the addition of pig slurry (PS), its manure (M) and its biochar (BC) affect soil microbial community and activity in three soils differing in SOM content (Regosol, Luvisol and Kastanozem). The evolution of different C and N fractions, microbial biomass C and N, enzyme activities and microbial community structure by the use of phospholipid fatty acid (PLFA) analysis was assessed for 60 days. Results showed that the different amendments had different effect on microbial properties depending on the soil type. The addition of M caused the highest increase in all microbial properties in the three soils, followed by PS. These changes were more intense in the soil with the lowest SOM (Regosol). The addition of M and PS caused changes in the microbial community structure in all soils, which were more related to the presence of available sources of N than to the labile fractions of C. The addition of BC was followed by increases in the proportions of fungi and Gram positive bacteria in the Regosol, while enhanced the proportion of actinobacteria in all soil types, related to increments in pH and soil C recalcitrance. Thus, native SOM determined the response of microbial communities to external inputs with different stability, soils with low SOM being more prone to increase microbial biomass and activity and change microbial community structure.

  20. Carbon Mineralizability Determines Interactive Effects on Mineralization of Pyrogenic Organic Matter and Soil Organic Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Whitman, Thea L.; Zhu, Zihua; Lehmann, Johannes C.

    2014-10-31

    Soil organic carbon (SOC) is a critical and active pool in the global C cycle, and the addition of pyrogenic organic matter (PyOM) has been shown to change SOC cycling, increasing or decreasing mineralization rates (often referred to as priming). We adjusted the amount of easily mineralizable C in the soil, through 1-day and 6-month pre-incubations, and in PyOM made from maple wood at 350°C, through extraction. We investigated the impact of these adjustments on C mineralization interactions, excluding pH and nutrient effects and minimizing physical effects. We found short-term increases (+20-30%) in SOC mineralization with PyOM additions in the soil pre-incubated for 6 months. Over the longer term, both the 6-month and 1-day pre-incubated soils experienced net ~10% decreases in SOC mineralization with PyOM additions. This was possibly due to stabilization of SOC on PyOM surfaces, suggested by nanoscale secondary ion mass spectrometry. Additionally, the duration of pre-incubation affected priming interactions, indicating that there may be no optimal pre-incubation time for SOC mineralization studies. We show conclusively that relative mineralizability of SOC in relation to PyOM-24 C is an important determinant of the effect of PyOM additions on SOC mineralization.

  1. Long-term citrus organic farming strategy results in soil organic matter recovery

    Science.gov (United States)

    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

  2. Leaching of organic acids from macromolecular organic matter by non-supercritical CO2

    Science.gov (United States)

    Sauer, P.; Glombitza, C.; Kallmeyer, J.

    2012-04-01

    The storage of CO2 in underground reservoirs is discussed controversly in the scientific literature. The worldwide search for suitable storage formations also considers coal-bearing strata. CO2 is already injected into seams for enhanced recovery of coal bed methane. However, the effects of increased CO2 concentration, especially on organic matter rich formations, are rarely investigated. The injected CO2 will dissolve in the pore water, causing a decrease in pH and resulting in acidic formation waters. Huge amounts of low molecular weight organic acids (LMWOAs) are chemically bound to the macromolecular matrix of sedimentary organic matter and may be liberated by hydrolysis, which is enhanced by the acidic porewater. Recent investigations outlined the importance of LMWOAs as a feedstock for microbial life in the subsurface [1]. Therefore, injection of CO2 into coal formations may result in enhanced nutrient supply for subsurface microbes. To investigate the effect of high concentrations of dissolved CO2 on the release of LMWOAs from coal we developed an inexpensive high-pressure high temperature system that allows manipulating the partial pressure of dissolved gases at pressures and temperatures up to 60 MPa and 120° C, respectively. In a reservoir vessel, gases are added to saturate the extraction medium to the desired level. Inside the extraction vessel hangs a flexible and inert PVDF sleeve (polyvinylidene fluoride, almost impermeable for gases), holding the sample and separating it from the pressure fluid. The flexibility of the sleeve allows for subsampling without loss of pressure. Coal samples from the DEBITS-1 well, Waikato Basin, NZ (R0 = 0.29, TOC = 30%). were extracted at 90° C and 5 MPa, either with pure or CO2-saturated water. Subsamples were taken at different time points during the extraction. The extracted LMWOAs such as formate, acetate and oxalate were analysed by ion chromatography. Yields of LMWOAs were higher with pure water than with CO2

  3. Role of organic matter on aggregate stability and related mechanisms through organic amendments

    Science.gov (United States)

    Zaher, Hafida

    2010-05-01

    To date, only a few studies have tried to simultaneously compare the role of neutral and uronic sugars and lipids on soil structural stability. Moreover, evidence for the mechanisms involved has often been established following wetting of moist aggregates after various pre-treatments thus altering aggregate structure and resulting in manipulations on altered aggregates on which the rapid wetting process may not be involved anymore. To the best of our knowledge, the objective of this work was to study the role of neutral and uronic sugars and lipids in affecting key mechanisms (swelling rate, pressure evolution) involved in the stabilization of soil structure. A long-term incubation study (48-wk) was performed on a clay loam and a silty-clay loam amended with de-inking-secondary sludge mix at three rates (8, 16 and 24 Mg dry matter ha-1), primary-secondary sludge mix at one rate (18 Mg oven-dry ha-1) and composted de-inking sludge at one rate (24 Mg ha-1). Different structural stability indices (stability of moist and dry aggregates, the amount of dispersible clay and loss of soil material following sudden wetting) were measured on a regular basis during the incubation, along with CO2 evolved, neutral and uronic sugar, and lipid contents. During the course of the incubations, significant increases in all stability indices were measured for both soil types. In general, the improvements in stability were proportional to the amount of C added as organic amendments. These improvements were linked to a very intense phase of C mineralization and associated with increases in neutral and uronic sugars as well as lipid contents. The statistical relationships found between the different carbonaceous fractions and stability indices were all highly significant and indicated no clear superiority of one fraction over another. Paper sludge amendments also resulted in significant decreases in maximum internal pressure of aggregate and aggregate swelling following immersion in water

  4. The nature of particulate organic matter settled on solid substrata

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, M.O.; Wagh, A.B.

    of the particulate material recovered from these two surfaces. Highly significant correlations were observed between the bacterial numbers and the measured parameters. This probably suggests that bacteria were the major source of the particulate matter settled... immerges dans un estuaire a ete analysce: bacteries, chlorophylle a, poids sec, matiere organique, carbone organique, azote, proteines, glueides et lipides. Aucune difference n'a etc dccelee dans lacomposition de la matiere organique et dans les...

  5. Organic matter addition in organic farming – Impact on root development and yields in maize and cowpea over dry seasons

    OpenAIRE

    Sangakkara, Dr Ravi; Bandaranayake, Mr P; Dissanayake, Ms U; Gajanayake, Ms J

    2008-01-01

    Organic matter and its proper management are vital in tropical organic farming to maintain productivity. A field study thus placed rice straw or Gliricidia leaves on the soil surface or the material was incorporated into soil. The impact of these treatments on soil moisture, root development and yields of organically grown maize or cowpea were evaluated in an Asian dry season. Incorporation increased soil moisture retention in the soil and hence induced better root growth, culminating in high...

  6. Effects of weathering of organic matter in the La Luna Formation, Maracaibo Basin, Western Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, N.

    1986-01-01

    The effect of weathering of organic matter in the La Luna Formation, the main source rock of Cretaceous oil in Western Venezuela was studied by means of organic petrography. Two outcrop samples from zero to about 10 cm depth were studied microscopically, both in whole rock and kerogen extract mode. This permitted recognizing some characteristics and consequences of weathering, such as: increased porosity of huminite and solid bitumens and the decrease of its reflectance (% anti Ro); disappearance of micrinite, presence of exudation substances and lower fluorescence emission of liptinite under blue light excitation. The mass reduction of the organic matter was determined by the difference of total organic carbon values, and by the weight reduction of the sample before and after extraction, in both weathered and unweathered samples. The loss of organic matter by weathering is considerable, as much as 87% in the first 0.5 cm of the weathering halo are lost.

  7. Role of Natural Organic Matter in Regulating the Partitioning of Fe(II, III) in Seawater

    Science.gov (United States)

    Guo, L.; Chen, M.; Roberts, K.; Santschi, P. H.

    2008-12-01

    Iron (Fe) is an essential micronutrient and plays an important role in controlling ocean productivity and carbon cycling. Fe has been shown to be mostly complexed with dissolved organic matter in seawater. However, the interaction of Fe with natural organic matter and how the quality and quantity of organic matter affect the chemical speciation of Fe in seawater remain poorly understood. Controlled laboratory experiments have been conducted to examine the partitioning of Fe(II, III) between dissolved, colloidal and particulate phases using radiotracers, model organic compounds, and ultrafiltration. In natural seawater, Fe is mostly partitioned in the colloidal and particulate phases, resulting in a logKd value of 7.3 and a logKc of 6.1, respectively. On average, about 25% of dissolved Fe-55 was found in the complexation of Fe with DOM could depress the bioavailability of Fe in seawater, the resultant Fe reduction may significantly enhance its solubility and bioavailability to marine organisms.

  8. Total N, total P and organic matters content in floodplain soils of Xianghai Nature Reserve

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Soil sediment samples of 10 layers with a spacing of 10 cm each were collected in different floodplain zones adjacent to Huolin River in the Xianghai Nature Reserve, and contents of total N, total P and organic matters were analyzed. The results showed that contents of total N, total P and organic matters were generally decreasing with the increase of distance from sample locations to the river channel, and contents of the three items were generally higher in the upper soil layer than that in the lower soil layer. The content variations displayed how flooding functions influenced nutrient matter content variations in floodplain soils since the flood inundation frequencies of the sample locations varied. The correlation analysis displayed that there were remarkable relativities between total N, total P and organic matters within definite spatial distance from the Huolin River channel.

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

    Directory of Open Access Journals (Sweden)

    Hannah J Brocke

    Full Text Available 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.

  10. Changes in different organic matter fractions during conventional treatment and advanced treatment

    Institute of Scientific and Technical Information of China (English)

    Chao Chen; Xiaojian Zhang; Lingxia Zhu; Wenjie He; Hongda Han

    2011-01-01

    XAD-8 resin isolation of organic matter in water was used to divide organic matter into the hydrophobic and hydrophilic fractions.A pilot plant was used to investigate the change in both fractions during conventional and advanced treatment processes.The treatment of hydrophobic organics (HPO), rather than hydrophilic organicas (HPI), should carry greater emphasis due to HPO's higher trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP).The removal of hydrophobic matter and its transmission into hydrophilic matter reduced ultimate DBP yield during the disinfection process.The results showed that sand filtration, ozonation, and biological activated carbon (BAC) filtration had distinct influences on the removal of both organic fractions.Additionally, the combination of processes changed the organic fraction proportions present during treatment.The use of ozonation and BAC maximized organic matter removal efficiency, especially for the hydrophobic fraction.In sum, the combination of pre-ozonation,conventional treatment, and O3-BAC removed 48% of dissolved organic carbon (DOC), 60% of HPO, 30% of HPI, 63% of THMFP,and 85% of HAAFP.The use of conventional treatment and O3-BAC without pre-ozonation had a comparable performance, removing 51% of DOC, 56% of HPO, 45% of HPI, 61% of THMFP, and 72% of HAAFP.The effectiveness of this analysis method indicated that resin isolation and fractionation should be standardized as an applicable test to help assess water treatment process efficiency.

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

    Science.gov (United States)

    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.

  12. Interaction between inorganic nutrients and organic matter in controlling coral reef communities in Glovers Reef Belize.

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  14. The removal characteristics of natural organic matter in the recycling of drinking water treatment sludge: Role of solubilized organics.

    Science.gov (United States)

    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.

  15. Microbial Community Responses to Increased Water and Organic Matter in the Arid Soils of the McMurdo Dry Valleys, Antarctica

    Directory of Open Access Journals (Sweden)

    Heather N Buelow

    2016-07-01

    Full Text Available The soils of the McMurdo Dry Valleys, Antarctica are an extreme polar desert, inhabited exclusively by microscopic taxa. This region is on the threshold of anticipated climate change, with glacial melt, permafrost thaw, and the melting of massive buried ice increasing liquid water availability and mobilizing soil nutrients. Experimental water and organic matter (OM amendments were applied to investigate how these climate change effects may impact the soil communities. To identify active taxa and their functions, total community RNA transcripts were sequenced and annotated, and amended soils were compared with unamended control soils using differential abundance and expression analyses. Overall, taxonomic diversity declined with amendments of water and organic matter. The domain Bacteria increased with both amendments while Eukaryota declined from 38% of all taxa in control soils to 8% and 11% in water and OM amended soils, respectively. Among bacterial phyla, Actinobacteria (59% dominated water-amended soils and Firmicutes (45% dominated OM amended soils. Three bacterial phyla (Actinobacteria, Proteobacteria, and Firmicutes were primarily responsible for the observed positive functional responses, while eukaryotic taxa experienced the majority (27 of 34 of significant transcript losses. These results indicated that as climate changes in this region, a replacement of endemic taxa adapted to dry, oligotrophic conditions by generalist, copiotrophic taxa is likely.

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

    Science.gov (United States)

    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.

  17. On the nature of organic matter from natural and contaminated materials : isolation methods, characterisation and application to geochemical modelling

    NARCIS (Netherlands)

    Zomeren, van A.

    2008-01-01

    Natural organic matter (NOM) is the material that is formed after the natural decomposition and transformation of dead plant and animal matter. The fresh organic matter (e.g. plant leaves or animal debris) is decomposed and transformed by microbial activity. As such, NOM is found everywhere in

  18. On the nature of organic matter from natural and contaminated materials : isolation methods, characterisation and application to geochemical modelling

    NARCIS (Netherlands)

    Zomeren, van A.

    2008-01-01

    Natural organic matter (NOM) is the material that is formed after the natural decomposition and transformation of dead plant and animal matter. The fresh organic matter (e.g. plant leaves or animal debris) is decomposed and transformed by microbial activity. As such, NOM is found everywhere in th

  19. On the nature of organic matter from natural and contaminated materials : isolation methods, characterisation and application to geochemical modelling

    NARCIS (Netherlands)

    Zomeren, van A.

    2008-01-01

    Natural organic matter (NOM) is the material that is formed after the natural decomposition and transformation of dead plant and animal matter. The fresh organic matter (e.g. plant leaves or animal debris) is decomposed and transformed by microbial activity. As such, NOM is found everywhere in th

  20. Trophodynamics and organic matter assimilation pathways in the northeast Chukchi Sea, Alaska

    Science.gov (United States)

    McTigue, Nathan D.; Dunton, Kenneth H.

    2014-04-01

    We analyzed trophic linkages in the northeast Chukchi Sea shelf based on the stable carbon and nitrogen isotopic analysis of 39 species collected in 2009 and 2010. To decipher organic matter assimilation pathways, benthic fauna were first categorized into nine trophic guilds based on their physical location in the seabed (epibenthic, surface, or subsurface), feeding mode (suspension feeder, deposit feeder, predator, or scavenger), and food source (suspended particulate organic matter, phytoplankton, zooplankton, sediment, microflora, meiofauna, or macrofauna). A discriminant function analysis (DFA) determined that feeding modes were predicted by stable isotope values at an overall classification success rate of 42%, although classification success of each individual guild varied from 0 to 66%. In some instances, stable isotopes classified trophic guilds incorrectly more often than correctly, suggesting high trophic redundancy in the system. A striking pattern was observed where the δ13C values of individuals in some trophic guilds, ranging from about -23 to -17‰, were substantially more 13C-enriched than representative end-members, which includes phytoplankton (-24.0‰), suspended particulate organic matter (-24.3‰), and bulk sediment organic matter (-23.3‰). In contrast, near-seafloor suspended particulate organic matter was significantly 13C-enriched compared to suspended particulate organic matter of near surface waters (p<0.05), and bulk sedimentary organic matter was more 13C-enriched than overlying phytoplankton at seven of 10 stations. This suggests the presence of an unmeasured 13C-enriched end-member that is a product of biogeochemical alteration and reworking by the sediment microbial community. Although the microbial community is difficult to quantify using bulk stable isotope analytical techniques, these results indicate it cannot be overlooked as a critical component and avenue through which large amounts of reduced carbon are assimilated by a

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

    Science.gov (United States)

    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.

  2. Understanding soil organic matter formation and stabilization (Philippe Duchaufour Medal Lecture)

    Science.gov (United States)

    Kögel-Knabner, Ingrid

    2015-04-01

    During the biomass formation/decomposition cycle carbon dioxide (CO2), the main gas driving global warming, is either released from or stabilized in the organic matter of soils. One of the most fundamental functions of soil organic matter is the provision of metabolic energy which drives soil biological processes. In essence, it is the transformation of carbon by plant, micro- and macro-biological processes that provides energy and results in the establishment of a cycle that connects above- and belowground energy transformations. The amount and type of organic matter accumulated in soils is controlled, among other factors by intrinsic soil properties, specifically soil texture and the associated aggregate structures. Soil development leads to the formation of aggregated structures composed of a highly complex mixture of different mineral and organic constituents. The resulting soil type specific carbon sequestration can strongly be affected by soil management, varying greatly with the type and intensity of land use. The processes of formation and stabilization of organic matter through organo-mineral interactions in aggregated soil structures are controlled at the sub-µm scale. Understanding the binding of organic matter in these fine soil structures is thus key to elucidate the biogeochemical soil processes that are part of the carbon cycle as well as to evaluate the effects of soil management on the carbon cycle. I will discuss open questions for understanding these processes and how we can approach them by combining state-of-the-art analytical techniques with innovative experiments.

  3. Soil Organic Matter in Forest Ecosystems of the Forest-tundra zone of Central Siberia

    Science.gov (United States)

    Mukhortova, Liudmila

    2010-05-01

    Our study was conducted on 17 forest sample plots in the forest-tundra zone of Central Siberia, Krasnoyarsk region, Russia. They were covered by larch/feather moss/shrub and larch/grass forest types growing on cryozems and podburs (Cryosols). The investigation was aimed at estimating soil organic matter storage and structure in forest ecosystems growing along the northern tree line. Such ecosystems have low rates of exchange processes and biological productivity. Estimating soil carbon in these forest types is important for a deeper understanding of their role in biogeochemical cycles and forecasting consequences of climate changes. Soil organic matter was divided into pools by biodegradation resistance level and, hence, different roles of these pools in biological cycles. The soil organic matter was divided into an easily mineralizable (LMOM) fraction, which includes labile (insoluble) (LOM) and mobile (soluble) (MOM) organic compounds, and a stable organic matter fraction that is humus substances bound with soil matrix. The forest-tundra soil carbon was found to total 30.9 to 125.9 tons/ha. Plant residues were the main part of the soil easily mineralizable organic matter and contained from 13.3 to 62.4% of this carbon. Plant residue carbon was mainly allocated on the soil surface, in the forest litter. Plant residues in the soil (dead roots + other "mortmass") were calculated to contribute 10-30% of the plant residues carbon, or 2.5-15.1% of the total soil carbon. Soil surface and in-soil dead plant material included 60-95% of heavily decomposed residues that made up a forest litter fermentation subhorizon and an "other mortmass" fraction of the root detritus. Mobile organic matter (substances dissolved in water and 0.1N NaOH) of plant residues was found to allocate 15-25% of carbon. In soil humus, MOM contribution ranged 14 to 64%. Easily mineralizable organic matter carbon appeared to generally dominate forest-tundra soil carbon pool. It was measured to

  4. Radiocarbon dating of fluvial organic matter reveals land-use impacts in boreal peatlands

    DEFF Research Database (Denmark)

    Hulatt, Chris J.; Kaartokallio, Hermanni; Oinonen, Markku

    2014-01-01

    This study measured the effects of land use on organic matter released to surface waters in a boreal peat catchment using radiocarbon dating of particulate and dissolved organic carbon (POC and DOC), DOC concentration, stable carbon and nitrogen isotope composition, and optical measurements. Undi...

  5. Molecular and microscopic insights into the persistence of soil organic matter in a red pine rhizosphere

    Science.gov (United States)

    Microbially-derived carbon inputs to soils play an important role in stabilization of soil organic matter (SOM), but detailed knowledge of basic mechanisms of carbon (C) cycling, such as stabilization of organic C compounds originating from rhizodeposition, is lacking. This study aimed to investigat...

  6. Mean residence time of kaolinite and smectite-bound organic matter in mozambiquan soils

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.; Buurman, P.

    2004-01-01

    To gain understanding about the process of global warming, it is essential to study the global C cycle. In the global C cycle, soil organic matter (SOM) is a major source and sink of atmospheric C. Turnover times of C in these soil organic compounds vary from hours to thousands of years. Clay minera

  7. Soil organic matter dynamics after the conversion of arable land to pasture

    NARCIS (Netherlands)

    Römkens, Paul F.A.M.; Plicht, Johannes van der; Hassink, Jan

    1999-01-01

    Conversion of arable land (maize) to pasture will affect the soil organic matter (SOM) content. Changes in the SOM content were studied using a size- and density-fractionation method and C-13 analysis. Twenty-six years of maize cropping had resulted in a depletion of carbon stored in the macro-organ

  8. Mean residence time of kaolinite and smectite-bound organic matter in mozambiquan soils

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.; Buurman, P.

    2004-01-01

    To gain understanding about the process of global warming, it is essential to study the global C cycle. In the global C cycle, soil organic matter (SOM) is a major source and sink of atmospheric C. Turnover times of C in these soil organic compounds vary from hours to thousands of years. Clay minera

  9. Hypoxia causes preservation of labile organic matter and changes seafloor microbial community composition (Black Sea)

    Science.gov (United States)

    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

  10. Highly Pristine Organic Matter in a Xenolith Clast in the Zag H Chrondrite

    Science.gov (United States)

    Kebukawa, Y.; Ito, M.; Zolensky, M. E.; Nakato, A.; Suga, H.; Takahashi, Y.; Takeichi, Y.; Mase, K.; Chan, Q.; Fries, M.; Kobayashi, K.

    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.

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

    Science.gov (United States)

    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

    2011-01-01

    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.

  12. Thermal Evolution of Organic Matter in Source Rocks—Experimental and Scanning Electron Microscopic Studies

    Institute of Scientific and Technical Information of China (English)

    姜开侠; 潘小明

    1991-01-01

    Five major froms(lamellar,banded,crack-like,dissceminated and segregated encrustation(of organic matter distribution in sourc rocks have been revealed under scanning electron microscope by using the heavy metal staining technique.The degree of organic impregnation is related to the amount of liquied hydrocarbons in the rocks,and from this relationship a rough estimation of organic matter can be made on the basis of electron microscopic observations.In conjunction with experimental studies it has been found that the distribution forms of organic matter are a function of its maturity in the process of thermal evolution and accordingly some microscopic criteria can be developed for the assessment of source rocks.

  13. Trace Metals And Organic Matter Diagenesis At The Oman Margin

    Digital Repository Service at National Institute of Oceanography (India)

    Alagarsamy, R.

    Trace Metals (e.g. Mn and Fe) play an important role as secondary oxidants in the degradation of sedimentary OM under sub-oxic conditions. Hence the remineralisation of organic constituents of sediments in the marine environment may significantly...

  14. Global effects of agriculture on fluvial dissolved organic matter

    DEFF Research Database (Denmark)

    Graeber, Daniel; Boëchat, Iola; Encina, Francisco

    2015-01-01

    DOM across climate zones of the northern and southern hemispheres. Both extensive and intensive farming altered fluvial DOM towards a more microbial and less plant-derived composition. Moreover, intensive farming significantly increased dissolved organic nitrogen (DON) concentrations. The DOM...

  15. Connections matter: Updraft merging in organized tropical deep convection

    Science.gov (United States)

    Glenn, I. B.; Krueger, Steven K.

    2017-07-01

    When tropical cumulus convection is organized, the spacing between updrafts is reduced, and deep convective cloud tops are higher. The relative importance of various processes through which organization increases cloud top heights is not well understood. It is likely that decreased spacing between updrafts in organized convection increases the frequency of convective updraft merging. What is the relative importance of merging in determining an updraft parcel's detrainment height? We investigated updraft parcel merging in organized deep convection using results from a large eddy simulation. We used Lagrangian parcel trajectories (LPTs) to locate merging events. LPTs that merge reach detrainment heights 1.5 km higher on average than LPTs which do not merge. Merged LPTs are more buoyant than nonmerged LPTs, implying less dilution due to entrainment. Using mutual information analysis, we found that merging, cloud base vertical velocity, and cloud base area are about equally important in determining parcel detrainment height.

  16. Organic matter in carbonaceous meteorites: past, present and future research.

    Science.gov (United States)

    Sephton, Mark A

    2005-12-15

    Carbonaceous meteorites are fragments of ancient asteroids that have remained relatively unprocessed since the formation of the Solar System. These carbon-rich objects provide a record of prebiotic chemical evolution and a window on the early Solar System. Many compound classes are present reflecting a rich organic chemical environment during the formation of the planets. Recent theories suggest that similar extraterrestrial organic mixtures may have acted as the starting materials for life on Earth.

  17. Land-use Effect on Stream Organic Matter Composition in Two Metropolitan Areas in USA

    Science.gov (United States)

    Duan, S.; Kaushal, S.; Amon, R. M.; Brinkmeyer, R.

    2011-12-01

    Urbanization is a form of land-use change that is increasing in coastal watersheds and may affect the quantity and quality of organic carbon delivered to streams and coastal ocean. Here, we examine the changes in optical and isotopic characteristics of organic matter in streams (Gwynns Fall and Buffalo Bayou) draining Baltimore and Houston Metropolitan Areas (USA), relative to nearby less affected forested watersheds. A summer longitudinal sampling in Gwynns Fall along a rural-urban gradient showed increases in dissolved organic carbon (DOC) and fluorescent protein to humic ratio but a decrease in specific UV absorption (SUVA). Parallel Factor modeling shows dominance of terrestrial component of DOC, and the ratio of an unknown component to the component of humic substance was high in urban watersheds and it was positively correlated impervious surface cover (an index of urbanization). Incubation experiments with leaves and stream algae suggest origin of decayed leaf leachate of this component. Conversely, DOM in Buffalo Bayou showed higher intensity of protein-like fluorescence, and the intensity increased longitudinal along a rural-urban gradient but decreased from low-flows to a flooding event. The difference in fluorescent organic matter composition between the two streams probably reflected different management of wastewater in watersheds. Surface sediment collected at sites of sub-watersheds of Gwynns Fall showed changes in particle size, elemental and isotopic composition with land use. Sediment incubations showed that higher temperature (due to urban heat island effect) enhanced loss of labile organic matter and release of refractory organic matter into stream water. Release of reactive soluble phosphorus, loss of nitrogen and reduction of sulfate also occurred at high incubating temperatures, along with mineralization of sediment organic matter. Bed sediment collected along Buffalo Bayou displayed a longitudinal decrease in N-15, probably reflecting the

  18. Reconstruction of Late Glacial and Holocene landscape-climatic changes in the central Selenga Middle Mountains based on the isotopic composition of organic matter

    Science.gov (United States)

    Golubtsov, V. A.; Ryzhov, Yu. V.

    2017-02-01

    The results of investigation into the composition of stable carbon and nitrogen isotopes of organic matter in the soils developed within soil-sedimentary sequences in the central part of the Selenga Middle Mountains in the Late Glacial and Holocene are presented. In the past 15000 years, the organic matter of the investigated soils has only been formed from the biomass of C3 plants (without the participation of C4 plants). This is confirmed by the of δ13C values from-27.00 to-23.35‰. A combined analysis of the parameters of the organic matter (Corg, Ntotal, C/N, δ13C, and δ15N) of soils formed in different periods makes it possible to assume that the isotopic composition of carbon and nitrogen reflects changes in the climate humidity during the Late Glacial and Holocene periods. The specified intervals of soil formation correspond to the climate humidification and stabilization of the surface owing to the development of dense vegetation. Aridization periods were characterized by the accumulation of sediments that buried soil horizons. The most pronounced stages of climate aridization occurred at the transition from the Late Glacial to the Holocene, from the Boreal to the Atlantic, and from the Atlantic to the Subboreal periods. The optimum soil-forming conditions existed in the periods of 11700-11000, 8800-6900, and 4700-1000 years ago, which is confirmed by the published data on the landscape-climatic changes in the adjacent areas in the past 15000 years.

  19. Biodegradability of anthropogenic organic matter in polluted rivers using fluorescence, UV, and BDOC measurements.

    Science.gov (United States)

    Knapik, Heloise G; Fernandes, Cristovão V S; de Azevedo, Julio Cesar R; dos Santos, Mauricius M; Dall'Agnol, Patrícia; Fontane, Darrell G

    2015-03-01

    The presence of highly urbanized and polluted areas affects both the quantity and the composition of organic matter in rivers through effluent loads and urban runoff discharges in watersheds. In such context, this paper aims to evaluate the biodegradability of anthropogenic organic matter in polluted rivers. Stream water samples were collected in three different sites considering a non-impacted area, a highly urbanized site located after a sewage treatment plant, and a site downstream of the watershed. For the biodegradation experiment, two adaptations of biodegradable dissolved organic carbon (BDOC) essay were evaluated to assess the decomposition rates between 10 days, with added nutrients, in the dark at 20 °C. The organic matter biodegradation was monitored by distinct parameters such as dissolved organic carbon (DOC), total organic carbon (TOC), particulate organic carbon (POC), fluorescence excitation-emission matrix (EEM), and UV absorbance measurements. The measured BDOC ranged from 0.8 mg/L at site IG01 (low anthropogenic occupation) to 4.2 mg/L at site IG02 (high impacted area), with averaged percentage of initial DOC ranging from 20 to 56 %, while an average of 28 % up to 95 % of POC can be considered as biodegradable. This pattern of biodegradation of fluorescent components was also observed through a decrease of tryptophan-like and tyrosine-like fluorescence peak intensity during the incubation time. The results also showed a higher decrease of humic-like fluorescence peak intensity at polluted sites (IG02 and IG05). Our experimental approach and monitoring strategy suggests that the evaluation of the organic matter biodegradability is essential to understand the fate and transformation mechanism of organic matter in urbanized and polluted rivers. And, considering a water quality planning and management perspective, this approach is important to identify the presence and location of organic compounds potentially important for dissolved oxygen

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

    Science.gov (United States)

    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.

  1. Sources and preservation of organic matter in recent sediment from the Changjiang (Yangtze River Estuary, China

    Directory of Open Access Journals (Sweden)

    Lü Xiaoxia

    2006-03-01

    Full Text Available The vertical distributions of bulk and molecular biomarker compositions in the samples from four sediment cores of the Changjiang (Yangtze River Estuary were determined. The changes in the bulk and molecular compositions with depth suggest that there have been recent changes in the marine autogenic and terrigenous supply. In the site at the boundary of the turbidity maximum (Site 8 and the most southern site (Site 26, the autogenic and allochthonous inputs make almost the same contribution to sedimentary organic matter. In the site close to the river mouth (Site 11, the organic matter mainly comes from the terrestrial input carried by the Changjiang water, whereas, in the most eastern site (Site 17, the organic matter consists of a mixture of recent and ancient Changjiang delta sedimentary residues. Significant downcore fluctuations were observed in the patterns of the bulk and molecular compositions, as well as in several biomarker ratios, which also indicates the different anoxic conditions at different depths of the core besides the source variation. In addition, the distributions of molecular compounds show that the organic matter is a mixture of immature and mature in the sediments of the four cores, which further indicates that the microbial activity is active in anoxic conditions, especially in the surface sediment. The vertical distributions of molecular compounds also show that the autogenic marine organic matter is more easily degraded, and that the molecular compounds evolve from unstable steric configurations to stable ones in the early diagenetic processes.

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

    Science.gov (United States)

    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. Prebiotic Organic Matter from the Center of the Galaxy

    Science.gov (United States)

    Halfen, DeWayne; Ziurys, Lucy M.

    2016-06-01

    The origins of life on Earth must have begun with simple organic compounds. A plausible source of such prebiotic molecules was the interstellar medium (ISM). Of the over 160 molecules that have been identified in interstellar gas, about half have been discovered in one source, Sagittarius B2(N), located in the Galactic Center. This giant molecular cloud is also home to many large organic species observed in the ISM. How complex these species can become is unknown. In order to accurately establish an inventory of potentially, prebiotic organic molecules, we completed a continuous spectral-line survey of Sgr B2(N) at the confusion limit using the Arizona Radio Observatory facilities: the Kitt Peak 12 m and the Submillimeter Telescope. The survey covers the 1, 2, and 3 mm atmospheric windows in the range 68 - 280 GHz, and about 15,000 individual spectral lines have been observed. Seventy-four molecules have been identified in the data, including several potential prebiotic species, such as glycolaldehyde, acetamide, and methyl isocyanate. These molecules are relatively abundant in Sgr B2(N), with fractional abundances of f ~ 10-10 - 10-12 relative to H2. Current results of this survey will be presented, along with its implications for interstellar organic chemistry and prebiotic synthesis. A comparison with organics found in comets and meteorites will also be discussed.

  4. Natural process and use of natural matters in organic viticulture

    Directory of Open Access Journals (Sweden)

    Sivčev Branislava V.

    2010-01-01

    Full Text Available During recent years organic viticulture has been developing in the leading viticulture countries worldwide. The organic viticulture has been defined as the application of procedures of organic agriculture in view of increasing the production of top quality grape and wine. All the aspects of the organic viticulture such as cultivating and maintaining the soil, ground cover plants and weed control, balanced nutrition of grapevine, growing systems, disease and pest control are carried out in view of increasing the quality and health safety of wine and table varieties. When making a choice of a cultivar, there are two key factors: an economic indicator-market perspective and characteristics of a cultivar. Traditional varieties are in advantage in comparison to newly created ones, new preparations, improved computerised forecast models contribute to the efficient protection from disease and pests. New I.C./PIWI varieties must show tolerance to low winter temperatures and/or spring frosts, real commercial value through the quality of fruit, wine, juice or table grapes, tolerance to diseases and pests, balanced relationship between fruit and wood ripening. The aim of this paper is to present organic viticulture through integral agroecosystem and traditionally applied procedures in viticulture.

  5. Biodegradation of Kupferschiefer black shale organic matter (Fore-Sudetic Monocline, Poland) by indigenous microorganisms.

    Science.gov (United States)

    Matlakowska, Renata; Sklodowska, Aleksandra

    2011-05-01

    This study provides the first evidence for the direct biodegradation of persistent organic matter extracted from the organic-rich polymetallic black shale ore Kupferschiefer, one of the most important sources of metals in the world. It was demonstrated that an enriched community of indigenous heterotrophic microorganisms isolated from black shale grown under aerobic conditions could utilize shale organic matter as the sole carbon and energy source. Colonization of shale organic matter was observed. The main biodegradation intermediates and products such as phosphonic acid dioctadecyl ester and isoindole-1,3 were detected in the aqueous phase of cultures. The bacterial community showed the ability to PAH biodegradation, assimilation of organic acids and esters as well as lipase activity. The intracellular accumulation of phosphorus by bacteria during growth on organic matter was confirmed. Strains within the genus Pseudomonas were found to dominate the bacterial population at the end of the experiment. The results of this study confirm that indigenous bacteria are likely to play a role in the biotransformation of black shale and can influence the geochemical cycles of ancient organic carbon in the deep terrestrial subsurface. This process may also occur in tailings ponds containing black shale, and cause the mobilization of potentially toxic compounds to the soil and groundwater.

  6. Effect of Dissolved Organic Matter on Basalt Weathering Rates under Flow Conditions

    Science.gov (United States)

    Dontsova, K.; Steefel, C. I.; Chorover, J. D.

    2009-12-01

    Rock weathering is an important aspect of soil formation that is tightly coupled to the progressive colonization of grain surfaces by microorganisms and plant tissue, both of which are associated with the exudation of complexing ligands and reducing equivalents that are incorporated into dissolved organic matter. As part of a larger hillslope experimental study being designed for Biosphere 2 (Oracle, AZ), we seek to determine how the presence and concentration of dissolved organic matter affects the incongruent dissolution rates of basaltic tuff. Saturated flow column experiments are being conducted using plant-derived soluble organic matter solutions of variable concentrations, and comparisons are being made to experiments conducted with malic acid, a low-molecular weight organic acid commonly exuded into the rhizosphere. Dissolved organic matter was extracted from Ponderosa Pine forest floor and was characterized for aqueous geochemical parameters (pH, EC, ion balance, DOC/TN) and also for DOC composition (UV-Vis, FTIR spectroscopy). Column effluents are being analyzed for major and trace cations, anions, silica and organic solutes. Dissolution rates of primary minerals and precipitation rates of secondary phases will be estimated by fitting the data to a numerical reactive transport model, CrunchFlow2007. At the end of the fluid flow experiment, column materials will be analyzed for biogeochemical composition to detect preferential dissolution of specific phases, the precipitation of new ones, and to monitor the associated formation of biofilms. The influence of organic solutions on weathering patterns of basalt will be discussed.

  7. Impact of natural organic matter properties on the kinetics of suspended ion exchange process.

    Science.gov (United States)

    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.

  8. Mechanisms of Heavy Metal Sequestration in Soils: Plant-Microbe Interactions and Organic Matter Aging

    Energy Technology Data Exchange (ETDEWEB)

    Teresa W.-M. Fan; Richard M. Higashi; David Crowley; Andrew N. Lane: Teresa A. Cassel; Peter G. Green

    2004-12-31

    For stabilization of heavy metals at contaminated sites, the three way interaction among soil organic matter (OM)-microbes-plants, and their effect on heavy metal binding is critically important for long-term sustainability, a factor that is poorly understood at the molecular level. Using a soil aging system, the humification of plant matter such as wheat straw was probed along with the effect on microbial community on soil from the former McClellan Air Force Base.

  9. The Organization Man Still Matters: Sinclair Lewis's Babbitt

    Directory of Open Access Journals (Sweden)

    Hartig, Marcel

    2008-01-01

    Full Text Available Ever since its publication Sinclair Lewis’s Babbitt (1922 has been a thorn in the side of many businessmen and organizations. Debates ranging from its literary merit to its content caused a stir during the ‘Roaring Twenties.’ However, the novel could also be read as a starting point in a series of writings about the evolution of modern business and businessmen. The paper argues that Babbitt traces developments of the contemporary organization man and his estrangement from his personal culture due to a boosting consumer culture. Lewis’s Babbitt thus is an early predecessor of sociologist William H. Whyte’s organization man and of the yuppie of the 1980s.

  10. The Organization Man Still Matters: Sinclair Lewis's Babbitt

    OpenAIRE

    Hartig, Marcel

    2008-01-01

    Ever since its publication Sinclair Lewis’s Babbitt (1922) has been a thorn in the side of many businessmen and organizations. Debates ranging from its literary merit to its content caused a stir during the ‘Roaring Twenties.’ However, the novel could also be read as a starting point in a series of writings about the evolution of modern business and businessmen. The paper argues that Babbitt traces developments of the contemporary organization man and his estrangement from his personal cultur...

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

    Directory of Open Access Journals (Sweden)

    Y. Schindler Wildhaber

    2012-01-01

    Full Text Available 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.

  12. Organic Matter Enrichment and Aggregate Stabilization in a Severely Degraded Ultisol After Reforestation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bin; PENG Xin-Hua

    2006-01-01

    Three types of soils: an eroded barren soil under continuous fallow, an eroded soil transplanted with Lespedeza shrubs(Lespedeza bicolor), and an eroded soil transplanted with camphor tree (Cinnamomum camphora) were investigated to quantify organic matter pools and aggregates in reforested soils using physical fractionation techniques and to determine aggregate stability in relation to the enrichment of soil organic carbon (SOC). Soil organic matter (SOM) was physically fractionalized into free particulate organic matter (fPOM), occluded particulate organic matter (oPOM), and mineralassociated organic matter (mOM). The SOM was concentrated on the surface soil (0-5 cm), with an average C sequestration rate of 20-25 g C m-2 year-1 over 14 years. As compared to the eroded barren land, organic C content of fPOM, oPOM,and mOM fractions of the soil under Lespedeza and under camphor tree increased 12-15, 45-54, and 3.1-3.5 times,respectively. A linear relationship was found between aggregate stability and organic C (r2 = 0.45, P < 0.01), oPOM(r2 = 0.34, P < 0.05), and mOM (r2 = 0.46, P < 0.01) of aggregates. The enrichment of organic C improved aggregate stability of the soil under Lespedeza but not that under camphor tree. However, further research is needed on the physical and biological processes involved in the interaction of soil aggregation and SOC sequestration in ecosystem.

  13. Relating hygroscopicity and composition of organic aerosol particulate matter

    CERN Document Server

    Duplissy, J; Prevot, A S H; Barmpadimos, I; Jimenez, J L; Gysel, M; Worsnop, D R; Aiken, A C; Tritscher, T; Canagaratna, M R; Collins, D R; Alfarra, M R; Metzger, A; Tomlinson, J; DeCarlo, P F; Weingartner, E; Baltensperger, U

    2011-01-01

    A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f(44)). m/z 44 is due mostly to the ion fragment CO(2)(+) for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfrau-joch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation b...

  14. Rethinking the Dutch Innovation Agenda: Management and Organization Matter Most

    NARCIS (Netherlands)

    H.W. Volberda (Henk); F.A.J. van den Bosch (Frans)

    2004-01-01

    textabstractIn this essay, we challenge the present dominant emphasis in the Dutch Innovation Debate on the creation of technological innovations, the focus on a few core technologies, and the allocation of more financial resources. We argue that managerial capabilities and organizing principles for

  15. Entrepreneurial behavior in organizations: Does job design matter?

    NARCIS (Netherlands)

    de Jong, J.P.J.; Parker, S.K.; Wennekers, A.R.M.; Wu, C.W.

    2015-01-01

    We take a first step to explore how organizational factors influence individual entrepreneurial behavior at work, by investigating the role of job design variables. Drawing on multiple-source survey data of 179 workers in a Dutch research and consultancy organization, we find that entrepreneurial be

  16. Evaluation of the toxicity of organic matter in marine sediments

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    The inhibitory effects of the organics from the sediment along the east coast of India on acetylcholinesterase (AChE) in-vitro were evaluated. Sediment samples collected from the surface layers at various depths were extracted. Each of the extracts...

  17. Distribution of particulate organic matter in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.C.; Rao, T.S.S.

    Particulate organic carbon (POC) of 161 water samples collected from 8 depths (surface to 1000 m) at 21 stations was measured The POC concentrations ranged from 154 to 554 mu g per litre at the surface and decreased in the upper 300 m water column...

  18. Potential uptake of dissolved organic matter by seagrasses and macroalgae

    NARCIS (Netherlands)

    Van Engeland, T.; Bouma, T.J.; Morris, E.P.; Brun Murillo, F.G.; Peralta, G.; Lara, M.; Hendriks, I.E.; Soetaert, K.E.R.; Middelburg, J.J.

    2011-01-01

    Dissolved organic nitrogen (DON) acts as a large reservoir of fixed nitrogen. Whereas DON utilization is common in the microbial community, little is known about utilization by macrophytes. We investigated the ability of the coexisting temperate marine macrophytes Zostera noltii, Cymodocea nodosa, a

  19. Entrepreneurial behavior in organizations: Does job design matter?

    NARCIS (Netherlands)

    de Jong, J.P.J.|info:eu-repo/dai/nl/168220849; Parker, S.K.; Wennekers, A.R.M.; Wu, C.W.

    2015-01-01

    We take a first step to explore how organizational factors influence individual entrepreneurial behavior at work, by investigating the role of job design variables. Drawing on multiple-source survey data of 179 workers in a Dutch research and consultancy organization, we find that entrepreneurial

  20. Degradation of Non-Diffusible Organic Matter in Biofilm Reactors

    DEFF Research Database (Denmark)

    Rohold, Lars Erik; Harremoës, Poul

    1993-01-01

    A simple laboratory test has been developed in order to demonstrate qualitatively, that the removal of non-diffusible organics in a biofilm reactor requires hydrolysis by extracellular enzymes in the bulk water of the reactor. The results demonstrate the effect of changing volume of bulk water...

  1. Rethinking the Dutch Innovation Agenda: Management and Organization Matter Most

    NARCIS (Netherlands)

    H.W. Volberda (Henk); F.A.J. van den Bosch (Frans)

    2004-01-01

    textabstractIn this essay, we challenge the present dominant emphasis in the Dutch Innovation Debate on the creation of technological innovations, the focus on a few core technologies, and the allocation of more financial resources. We argue that managerial capabilities and organizing principles for

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

    Science.gov (United States)

    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

  3. Stabilization of organic matter in the raised-bed soils of tidal swamplands is influenced by the types and the amounts of organic matter application

    Directory of Open Access Journals (Sweden)

    A R Saidy

    2015-05-01

    Full Text Available Farmers in tidal swamplands annually added organic matter (OM onto the raised beds to maintain organic matter contents and thereby maintain soil productivity of the raised beds. This experiment aimed to study the influence of the types and the amounts of OM on the stabilization of organic matter in the raised-bed soils. Four types of OM: rice straw, eceng gondok (Eichornia crassipes, purun tikus  (Eleocharis dulcis and mixed  rice straw-eceng gondok were added to a 27-year raised bed soil with 4 different rates: 0, 0.5, 1.0 and 2.0  of maximum sorption capacity (Qmax, and the OM stabilization was quantified after 10 weeks of OM addition.  Results of this study showed with the exception of rice straw, OM addition to soil resulted in increases in the mineralization of soil OM thereby inducing priming effect. Addition of rice straw at rate of 0.5 of Qmax resulted in stabilization of 46% added OM, while only 30% and 37% of added OM was stabilized when OM was added to soils at rates of 1.0 and 2.0 Qmax, respectively.  This study showed that the stabilization of OM in raised bed soils were influenced by the chemical composition of OM and the amount of added OM.

  4. Determining the spatial variability of wetland soil bulk density, organic matter, and the conversion factor between organic matter and organic carbon across coastal Louisiana, U.S.A.

    Science.gov (United States)

    Wang, Hongqing; Piazza, Sarai C.; Sharp, Leigh A.; Stagg, Camille L.; Couvillion, Brady R.; Steyer, Gregory D.; McGinnis, Thomas E.

    2016-01-01

    Soil bulk density (BD), soil organic matter (SOM) content, and a conversion factor between SOM and soil organic carbon (SOC) are often used in estimating SOC sequestration and storage. Spatial variability in BD, SOM, and the SOM–SOC conversion factor affects the ability to accurately estimate SOC sequestration, storage, and the benefits (e.g., land building area and vertical accretion) associated with wetland restoration efforts, such as marsh creation and sediment diversions. There are, however, only a few studies that have examined large-scale spatial variability in BD, SOM, and SOM–SOC conversion factors in coastal wetlands. In this study, soil cores, distributed across the entire coastal Louisiana (approximately 14,667 km2) were used to examine the regional-scale spatial variability in BD, SOM, and the SOM–SOC conversion factor. Soil cores for BD and SOM analyses were collected during 2006–09 from 331 spatially well-distributed sites in the Coastwide Reference Monitoring System network. Soil cores for the SOM–SOC conversion factor analysis were collected from 15 sites across coastal Louisiana during 2006–07. Results of a split-plot analysis of variance with incomplete block design indicated that BD and SOM varied significantly at a landscape level, defined by both hydrologic basins and vegetation types. Vertically, BD and SOM varied significantly among different vegetation types. The SOM–SOC conversion factor also varied significantly at the landscape level. This study provides critical information for the assessment of the role of coastal wetlands in large regional carbon budgets and the estimation of carbon credits from coastal restoration.

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

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, Kathryn L. [Univ. of Illinois, Chicago, IL (United States)

    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. 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, Colorado, (6

  6. Dissolved organic matter and lake metabolism. Technical progress report, 1 July 1976--30 June 1977

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, R.G.

    1977-01-01

    Progress is reported on investigations on the qualitative and quantitative cycling of particulate and dissolved organic matter within lakes and their drainage basins. Interactions of dissolved organic matter with inorganic nutrient cycling and regulation of the photosynthetic and decompositional metabolism of micro- and macroflora remain the focal point of these studies. Major efforts were directed towards the sources fates, pathways, and interactions of dissolved organic matter in inorganic chemical cycling; allochthonous sources, metabolism en route, and inputs to the lake systems of increasing stages of eutrophication; and the relationships of these compounds to the nutrient physiology and metabolism of phytoplankton, sessile algae, macrophytes, and bacterial populations. Results of studies carried out in a freshwater lake in Michigan (Lawrence Lake) are reported. 165 references.

  7. Enhanced rates of particulate organic matter remineralization by microzooplankton are diminished by added ballast minerals

    Directory of Open Access Journals (Sweden)

    F. A. C. Le Moigne

    2013-02-01

    Full Text Available To examine the potentially competing influences of microzooplankton and calcite mineral ballast on organic matter remineralization, we incubated diatoms in darkness in rolling tanks with and without added calcite minerals (coccoliths and microzooplankton (rotifers. Concentrations of particulate organic matter (POM, suspended or in aggregates, of dissolved organic matter (DOM, and of dissolved inorganic nutrients were monitored over 8 days. The presence of rotifers enhanced the remineralization of ammonium and phosphate, but not dissolved silicon, from the biogenic material, up to 40% of which became incorporated into aggregates early in the experiment. Added calcite resulted in rates of excretion of ammonium and phosphate by rotifers that were depressed by 67% and 36%, respectively, demonstrating the potential for minerals to inhibit the destruction of POM in the water column by zooplankton. Lastly, the presence of the rotifers and added calcite minerals resulted in more rapid kinetics of aggregation, although not a greater overall amount of aggregation during the experiment.

  8. Observed effects of soil organic matter content on the microwave emissivity of soils

    Science.gov (United States)

    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.

  9. Lattice Boltzmann prediction of transport properties in reconstructed nanostructures of organic matters in shales

    CERN Document Server

    Chen, Li; Zhang, Lei; Tao, Wenquan

    2014-01-01

    Size, morphology and distributions of pores in organic matters of shale matrix are discussed based on high resolution images from experiments in the literature. 150 nanoscale structures of the organic matters are then reconstructed by randomly placing pore spheres with different diameters and overlap tolerances. Effects of porosity, the mean diameter and the overlap tolerance on void space connectivity and pore size distribution are studied. Further, a pore-scale model based on the Lattice Boltzmann method is developed to predict the Knudsen diffusivity and permeability of the reconstructed organic matters. The simulation results show that the mean pore diameter and overlap tolerance significantly affect the transport properties. The predicted Knudsen effective diffusivity is compared with Bruggeman equation and it is found that this equation underestimate the tortuosity. A modified Bruggeman equation is proposed based on the simulation results. The predicted intrinsic permeability is in acceptable agreement ...

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

    Science.gov (United States)

    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.

  11. Distribution and sources of organic matter in surface marine sediments across the North American Arctic margin

    Science.gov (United States)

    Goñi, Miguel A.; O'Connor, Alison E.; Kuzyk, Zou Zou; Yunker, Mark B.; Gobeil, Charles; Macdonald, Robie W.

    2013-09-01

    As part of the International Polar Year research program, we conducted a survey of surface marine sediments from box cores along a section extending from the Bering Sea to Davis Strait via the Canadian Archipelago. We used bulk elemental and isotopic compositions, together with biomarkers and principal components analysis, to elucidate the distribution of marine and terrestrial organic matter in different regions of the North American Arctic margin. Marked regional contrasts were observed in organic carbon loadings, with the highest values (≥1 mg C m-2 sediment) found in sites along Barrow Canyon and the Chukchi and Bering shelves, all of which were characterized by sediments with low oxygen exposure, as inferred from thin layers (cutin acids) all indicate marked regional differences in the proportions of marine and terrigenous organic matter present in surface sediments. Regions such as Barrow Canyon and the Mackenzie River shelf were characterized by the highest contributions of land-derived organic matter, with compositional characteristics that suggested distinct sources and provenance. In contrast, sediments from the Canadian Archipelago and Davis Strait had the smallest contributions of terrigenous organic matter and the lowest organic carbon loadings indicative of a high degree of post-depositional oxidation.

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

    Science.gov (United States)

    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.

  13. Influence of Soil Organic Matter Content on Abundance and Biomass of Earthworm (Oligochaeta: Lumbricidae Populations

    Directory of Open Access Journals (Sweden)

    Hristo Valchovski

    2016-06-01

    Full Text Available The current study explores the influence of soil organic matter content on abundance and biomass of earthworm communities. The observation was carried out on three type of soils: PellicVertisols (very fine texture, Cromi-Vertic Luvisols (fine texture and Calcaric Fluvisols (mediumtexture from the Balkan Peninsula (Bulgaria. The field experiment was provided on uncultivatedplots. In the studied area earthworm fauna comprises of four species: Aporrectodea rosea,Aporrectodea caliginosa, Lumbricus terrestris and Octolasion lacteum. We found peregrine lumbricidtaxa, which are widely distributed in European soils. Our study demonstrated that soil organicmatter has a positive effect on lumbricid populations. It was revealed that augmentation of soilorganic matter favours characteristics of earthworm communities. The soil organic matter contentand earthworm abundance are in strong positive correlation (r > 0.981. The same relationship wasrevealed between the biomass of lumbricid fauna and amount of soil organic matter (r > 0.987. Insum, the soil organic matter could be used as an indicator for earthworm communities inuncultivated soils.

  14. [Spatial interpolation of soil organic matter using regression Kriging and geographically weighted regression Kriging].

    Science.gov (United States)

    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.

  15. Atmospheric fluxes of organic matter to the Mediterranean Sea: contribution to the elemental C: N: P ratios of surface dissolved organic matter

    Science.gov (United States)

    Djaoudi, Kahina; Barani, Aude; Hélias-Nunige, Sandra; Van Wambeke, France; Pulido-Villena, Elvira

    2016-04-01

    It has become increasingly apparent that atmospheric transport plays an important role in the supply of macro- and micro-nutrients to the surface ocean. This atmospheric input is especially important in oligotrophic regions where the vertical supply from the subsurface is low particularly during the stratification period. Compared to its inorganic counterpart, the organic fraction of atmospheric deposition and its impact on surface ocean biogeochemistry has been poorly explored. In the ocean, carbon export to depth (and therefore, its long term storage with presumed consequences on climate) occurs both through particle sedimentation and through the transfer of dissolved organic matter (DOM) via diffusion or convection. DOM export from the surface ocean represents up to 50% of total organic carbon flux to the deep ocean in oligotrophic regions such as the Mediterranean Sea. The efficiency of this C export pathway depends, among others, on the elemental C: N: P ratios of surface DOM which might be affected by the relative contribution of microbial processes and allochthonous sources. This work reports a one-year time-series (April 2015-April 2016) of simultaneous measurements of (1) total (dry + wet) atmospheric fluxes of organic carbon, organic nitrogen, and organic phosphorus and (2) concentration of dissolved organic carbon, dissolved organic nitrogen, and dissolved organic phosphate at the surface layer (0-200 m) in the NW Mediterranean Sea. Atmospheric and oceanic surveys were conducted at the Frioul and ANTARES sites, respectively, operated by the long-term observation network MOOSE (Mediterranean Oceanic Observation System for the Environment).

  16. How Decisions Can Be Organized - and Why It Matters

    Directory of Open Access Journals (Sweden)

    Michael Christensen

    2013-12-01

    Full Text Available Recent theoretical advances allow organizational designers and managers to better understand how decision processes can be improved. These advances allow managers to address a number of critical questions about the structure and process of decision making, issues that are relevant for any kind of organization be it social, political, or economic. Can we add another employee somewhere in the decision process to increase economic performance? Can we add or eliminate a channel of communication to raise the quality of decisions? What level of skill is worth paying for when we hire a decision maker? Is it a good idea to push decision makers beyond their current capacity if doing so increases their error rate by five percent? Where does the injection of inexperienced decision makers hurt the least? We describe an organizational design approach that provides answers to such questions, and we offer specific guidelines that managers can use to improve decision making in their organizations.

  17. Relating hygroscopicity and composition of organic aerosol particulate matter

    Directory of Open Access Journals (Sweden)

    J. Duplissy

    2010-08-01

    Full Text Available A hygroscopicity tandem differential mobility analyzer (HTDMA was used to measure the water uptake (hygroscopicity of secondary organic aerosol (SOA formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS, and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f44. m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF or "κorg" parameter, and f44 was determined and is given by κorg=2.2×f44−0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f44 is correlated with the photochemical age of an air mass.

  18. Relating hygroscopicity and composition of organic aerosol particulate matter

    Directory of Open Access Journals (Sweden)

    J. Duplissy

    2011-02-01

    Full Text Available A hygroscopicity tandem differential mobility analyzer (HTDMA was used to measure the water uptake (hygroscopicity of secondary organic aerosol (SOA formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS, and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f44. m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF or "ϰorg" parameter, and f44 was determined and is given by ϰorg = 2.2 × f44 − 0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f44 is correlated with the photochemical age of an air mass.

  19. Conventional crop management effects on soil organic matter characteristics

    OpenAIRE

    2003-01-01

    International audience; A Mediterranean soil affected by long-term crop management systems was evaluated to identify the best indicators of its quality. Selected characteristics included total soil organic carbon (TOC), light fraction carbon (LFC), acid hydrolyzable and water-soluble carbohydrates carbon (AHG-C and WSC-C), phenolic carbon (PC), mineralizable carbon (Q), microbial biomass carbon (MB-C) and metabolic quotients (qCO$_2$ and qD). Soil samples were taken under natural grass (NG), ...

  20. Role of effluent organic matter in the photochemical degradation of compounds of wastewater origin.

    Science.gov (United States)

    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)O2), 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)O2. In all water samples, cimetidine degraded by reaction with (1)O2 (>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)O2 pathways. Finally, compound degradation rate constants normalized to the rate of light absorption by water correlated with E2/E3 ratios (sample

  1. Do incentives matter? Providing benefits to families of organ donors.

    Science.gov (United States)

    Bryce, C L; Siminoff, L A; Ubel, P A; Nathan, H; Caplan, A; Arnold, R M

    2005-12-01

    Whether the number of organs available for transplant would be positively or negatively affected by providing benefits to families of organ donors has been debated by policymakers, ethicists and the transplant community at large. We designed a telephone survey to measure public opinion regarding the use of benefits in general and of five types in particular: funeral benefits, charitable contributions, travel/lodging expenses, direct payments and medical expenses. Of the 971 adults who completed the survey (response rate = 69%), all were from Pennsylvania households, 45.6% were registered organ donors, and 51.7% were nonwhite. Although 59% of respondents favored the general idea of incentives, support for specific incentives ranged from 53% (direct payment) to 84% (medical expenses). Among those registered as donors, more nonwhites than whites supported funeral benefits (88% vs. 81%; p = 0.038), direct payment (63% vs. 41%; p benefits would not influence their own behavior concerning donation but would influence the behavior of others. While benefits appear to be favored, their true impact can only be assessed through pilot programs.

  2. Accounting for microbial habitats in modeling soil organic matter dynamics

    Science.gov (United States)

    Chenu, Claire; Garnier, Patricia; Nunan, Naoise; Pot, Valérie; Raynaud, Xavier; Vieublé, Laure; Otten, Wilfred; Falconer, Ruth; Monga, Olivier

    2017-04-01

    The extreme heterogeneity of soils constituents, architecture and inhabitants at the microscopic scale is increasingly recognized. Microbial communities exist and are active in a complex 3-D physical framework of mineral and organic particles defining pores of various sizes, more or less inter-connected. This results in a frequent spatial disconnection between soil carbon, energy sources and the decomposer organisms and a variety of microhabitats that are more or less suitable for microbial growth and activity. However, current biogeochemical models account for C dynamics at the macroscale (cm, m) and consider time- and spatially averaged relationships between microbial activity and soil characteristics. Different modelling approaches have intended to account for this microscale heterogeneity, based either on considering aggregates as surrogates for microbial habitats, or pores. Innovative modelling approaches are based on an explicit representation of soil structure at the fine scale, i.e. at µm to mm scales: pore architecture and their saturation with water, localization of organic resources and of microorganisms. Three recent models are presented here, that describe the heterotrophic activity of either bacteria or fungi and are based upon different strategies to represent the complex soil pore system (Mosaic, LBios and µFun). These models allow to hierarchize factors of microbial activity in soil's heterogeneous architecture. Present limits of these approaches and challenges are presented, regarding the extensive information required on soils at the microscale and to up-scale microbial functioning from the pore to the core scale.

  3. Organic Matter Decomposition in Red Soil as Affected by Earthworms

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The earthworms Pheretima carnosa, Drawida gisti and Eisenia foetida were studied to compare their contributions to the decomposition of various organic materials surface-applied on red soil in a 165-day greenhouse experiment. The native species Pheretima carnosa and Drawida gisti were equally effective in accelerating the decomposition of maize residue, according to fresh body weight, while commercial species Eisenia foetida had no significant influence on dry mass loss of maize residue. Liming with CaCO3 or CaO showed little effect on maize residue breakdown involved by Pheretima carnosa, but it inhibited this process involved by Drawida gisti. The capability of Pheretima carnosa to the decomposition of five kinds of organic materials was thoroughly examined. The dry mass losses in worm treatments were in the order of soybean residue > maize residue > pig manure > semi-decayed maize > ryegrass. However, the relative contributions of the earthworm to dry mass loss were in the order of pig manure (89.8%) > semi-decayed maize residue (49.1%) > maize residue (29.4%) > soybean residue (20.9%) > ryegrass residue (16.5%). Pheretima carnosa consumed 20~120 mg dry weight of organic material per gram fresh weight of biomass per day.

  4. Pre-Biological Evolution of Organic Matter in the Universe

    Science.gov (United States)

    Wiebe, D. Z.

    2017-05-01

    Discovery of interstellar molecules has become one of the most prominent findings of 20th century. Initially (since late 1930-ies) only simple two-atom compounds have been known. However, the rapid development of radioastronomy during post-war years has allowed expanding this list significantly. Now, the number of known interstellar and circumstellar molecules approaches two hundred (not counting isomers and isotopologues). Among them we see both simple and quite complex molecules. The largest molecules with solid identification consist of 12 atoms (CH3OC2H5, C3H7CN). Nearly all molecules with more than five atoms represent are organic. More than once even discovery of the simplest amino acid (glycine) in the interstellar medium had been reported. While later all these reports has been refuted, there is no doubt that this is a purely technical problem, and there are no fundamental obstacles on a pathway to interstellar synthesis of simplest amino acids. Definitely, even more complex organic structures are present in the interstellar medium, like fullerenes and some kind of aromatic particles. Recently, this diversity quite often became an incentive to suggest that organic species might have arrived to Earth (and other forming planets) in a "ready-to-use" form. However, one has to remember that numerous factors causing effective molecule destruction are in action in the interstellar medium, in the vicinity of young stars, and in protoplanetary disks.

  5. Natural Organic Matter as Global Antennae for Primary Production

    Science.gov (United States)

    Van Trump, J. Ian; Rivera Vega, Fransheska J.

    2013-01-01

    Abstract Humic substances (HS) are high-molecular-weight complex refractory organics that are ubiquitous in terrestrial and aquatic environments. While resistant to microbial degradation, these compounds nevertheless support microbial metabolism via oxidation or reduction of their (hydro)quinone moieties. As such, they are known to be important electron sinks for respiratory and fermentative bacteria and electron sources for denitrifying and perchlorate-reducing bacteria. HS also strongly promote abiotic reduction of Fe(III) when irradiated with light. Here, we show that HS-enhanced Fe(III) photoreduction can also drive chemolithotrophic microbial respiration by producing Fe(II), which functions as a respiratory electron donor. Due to their molecular complexity, HS absorb most of the electromagnetic spectrum and can act as broad-spectrum antennae converting radiant energy into bioavailable chemical energy. The finding that chemolithotrophic organisms can utilize this energy has important implications for terrestrial, and possibly extraterrestrial, microbial processes and offers an alternative mechanism of radiation-driven primary productivity to that of phototrophy. Key Words: Deep subsurface biosphere—Chemolithotrophic microorganisms—Organic matter—Geochemistry—Iron-oxidizing bacteria. Astrobiology 13, 476–482. PMID:23683047

  6. Quantity and nature of water-extractable organic matter from sandy loam soils with potato cropping managements

    Science.gov (United States)

    Water-extractable organic matter (WEOM) is part of the soil labile organic matter components. In this work, we evaluated the level and nature of soil WEOM from a long-term (6-year) potato crop rotation field experiment. The contents of water-extractable organic C (WEOC) were higher in continuous pot...

  7. Detecting refractory organic matter on Mars: how derivatization will help

    Science.gov (United States)

    Freissinet, C.; Kashyap, S.; Glavin, D. P.; Buch, A.; Brault, A.; Mahaffy, P. R.

    2012-12-01

    The search for organic molecules on Mars can provide important first clues of extinct or extant biota on the planet. Gas Chromatography Mass Spectrometry (GC-MS) is currently the most relevant space-compatible analytical tool for the detection of organics. Nevertheless, GC separation is intrinsically restricted to volatile molecules, and a lot of the molecules of exobiological interest are refractory or polar. To analyze these organics such as amino acids, nucleobases and carboxylic acids, an additional derivatization step is required to transform them into volatile derivatives that are amenable to GC analysis. As part of the Sample Analysis at Mars (SAM) experiment onboard Mars Science Laboratory (MSL) Curiosity rover which successfully landed on Mars on August 5, 2012, a single-step protocol of extraction and chemical derivatization with the silylating reagent N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide MTBSTFA has been developed to reach a wide range of astrobiology-relevant refractory organic molecules. Seven cups on SAM are devoted to MTBSTFA derivatization. However, this chemical reaction adds a protective silyl group in place of each labile hydrogen, which make the molecule non-identifiable in common mass spectra libraries. We thus created an extended library of mass spectra of derivatized compounds of interest, considering their potential occurrence in Mars soils. We then looked specifically at these compounds using the existing and the newly created library, in various Mars analog soils. To enable a more accurate interpretation of the in situ derivatization GC-MS results that will be obtained by SAM, the lab experiments are performed in the restrictive conditions of the SAM flight instrument. First experiments display promising results, the system permitting an extraction and detection of several proteinic amino and carboxylic acids from Martian representative matrices. Preliminary results show a lack of derivatized organic molecules in

  8. Heavy metals and arsenic fixation into freshwater organic matter under Gammarus pulex L. influence.

    Science.gov (United States)

    Schaller, Joerg; Mkandawire, Martin; Gert Dudel, E

    2010-07-01

    Organic sediments are a main sink for metal pollutants in aquatic systems. However, factors that make sediments a sink of metals and metalloids are still not clear. Consequently, we investigate the role of invertebrate shredders (Gammarus pulex L.) on quality of metal and arsenic fixation into organic partitions of sediment in the course of litter decay with laboratory microcosm experiments. During the decomposition of leaf litter, G. pulex significantly facilitated the development of small particles of organic matter. The capacity of metal fixation was significantly higher in smaller particles than leaf litter and litter residuals. Thus, G. pulex enhanced metal fixation into the organic partition of sediments by virtue of increasing the amount smaller particles in the aquatic system. Furthermore, invertebrates have a significant effect on formation of dissolved organic matter and remobilization of cobalt, molybdenum and cesium, but no significant effect on remobilization of all other measured elements.

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

    Science.gov (United States)

    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.

  10. What bacteria leave behind: bacterial organic matter quality and biomarker signals

    DEFF Research Database (Denmark)

    Piil, Kristoffer; Schramm, Andreas; Niggemann, Jutta;

    WHAT BACTERIA LEAVE BEHIND: BACTERIAL ORGANIC MATTER QUALITY AND BIOMARKER SIGNALS Knowledge of the cellular content of bacterial biomarkers (D-amino acids and muramic acid) provides us with a powerful tool to trace production and fate of bacterially derived organic matter. The biochemical...... composition of prokaryotic cells was studied by re-growing a mixed community of native sediment bacteria in anoxic sediment pore water. Cellular concentrations of L- and D-amino acids and amino sugars were determined by high performance liquid chromatography (HPLC). The proportion of Archaea, Gram positive...

  11. Some features of soil organic matter in parks and adjacent residential areas of Moscow

    Science.gov (United States)

    Prokof'eva, T. V.; Rozanova, M. S.; Poputnikov, V. O.

    2013-03-01

    The humus-accumulative horizons of soils from two natural-historical parks of Moscow and the adjacent residential areas were studied. An increase in the concentration of organic matter was observed in the soils of the residential areas. A tendency toward the formation of fulvate humus typical for southern taiga soils persisted in the low-carbonate nongleyed humus-accumulative horizons. At the same time, the transformation rate, character, and content of organic matter in the urban soils were strongly affected by the contamination, calcareous invasion, and remediation of the soils and sediments.

  12. Thermal alteration of water extractable organic matter in climosequence soils from the Sierra Nevada, California

    Science.gov (United States)

    Santos, Fernanda; Russell, David; Berhe, Asmeret Asefaw

    2016-11-01

    In the next decades, the influence of wildfires in controlling the cycling and composition of soil organic matter (SOM) globally and in the western U.S. is expected to grow. While the impact of fires on bulk SOM has been extensively studied, the extent at which heating of soil affects the soluble component of SOM remains unclear. Here we investigated the thermal transformations of water-extractable organic matter (WEOM) by examining the changes in the distribution of carbon (C) functional groups in WEOM from soils heated at low and intermediate temperatures. WEOM (exported from soils to rivers in the Sierra Nevada and beyond.

  13. Effects of Manipulated Above- and Belowground Organic Matter Input on Soil Respiration in a Chinese Pine Plantation

    OpenAIRE

    Juan Fan; Jinsong Wang; Bo Zhao; Lianhai Wu; Chunyu Zhang; Xiuhai Zhao; Gadow, Klaus V.

    2015-01-01

    Alteration in the amount of soil organic matter input can have profound effect on carbon dynamics in forest soils. The objective of our research was to determine the response in soil respiration to above- and belowground organic matter manipulation in a Chinese pine (Pinus tabulaeformis) plantation. Five organic matter treatments were applied during a 2-year experiment: both litter removal and root trenching (LRRT), only litter removal (LR), control (CK), only root trenching (RT) and litter a...

  14. Soil organic matter stratification as an indicator of soil quality

    OpenAIRE

    Franzluebbers, A.J.

    2002-01-01

    Metadata only record This paper explores the potential for using a ration of the stratification of soil organic C and N pools by depth as an indicator of soil quality. Stratification ratios offer a more universal indicator of soil quality, allowing comparison of soils across different soil types and climates. The ratios calculated for Georgia, Texas, and Alberta/British Colombia were, respectively, 1.1, 1.2, and 1.9 under conventional tillage, and 3.0, 2.0, and 2.1 under no tillage. High s...

  15. How Decisions Can Be Organized - and Why It Matters

    DEFF Research Database (Denmark)

    Christensen, Michael; Knudsen, Thorbjørn

    2013-01-01

    of organization be it social, political, or economic. Can we add another employee somewhere in the decision process to increase economic performance? Can we add or eliminate a channel of communication to raise the quality of decisions? What level of skill is worth paying for when we hire a decision maker......Recent theoretical advances allow organizational designers and managers to better understand how decision processes can be improved. These advances allow managers to address a number of critical questions about the structure and process of decision making, issues that are relevant for any kind...

  16. Hypolithic Biocrust in the Larsemann Hills of East Antarctica: Spatial Patterns, Organic Matter Stabilization, Comparison with Endolithic Systems

    Science.gov (United States)

    Mergelov, Nikita; Dolgikh, Andrey; Shorkunov, Ilya; Zazovskaya, Elya; Shishkov, Vasily; Pochikalov, Alexander

    2017-04-01

    The survey conducted in the Larsemann Hills oasis of East Antarctica (69°24'S, 76°14'E) revealed that hypolithic and endolithic bio-abiotic systems occupy from 20 to 60% of the wet valleys floors and slopes area. As in many other parts of Antarctica a significant portion of organic matter in Larsemann Hills is produced in cryptic niches inside the fissure network of hard rocks or under the stone pavements on loose sediments. The dominant autotrophic components of such ecosystems are cyanobacteria and green algae, mainly in the form of biofilms. However moss dominated communities could form distinct patterns within hypolithic biocrust. The spatial distribution of various types of hypolithic biocrusts, its thickness, moisture content, carbon and nitrogen content/stocks, as well as C/N ratios were studied at a detailed scale at several key sites along the grid of 10x10 m with a step of 1 m (121 sampling points each). The data received are evident that microbial and cryptogamic photoautotrophs activity in hidden habitats under the stone pavements could lead to the substantial organic matter accumulation in extreme environment of East Antarctica - up to 5% of C and 0.4% of N. However the radiocarbon data indicate that in many cases the values of fraction modern (F14C) exceed "1" which means that organic matter in hypolithic biocrust is not preserved in a long-term period. This contrasts with 14C "ages" of endolithic systems on surrounding slopes of the valley exceeding 500 and sometimes 1000 yr BP. We found that once hypolithic organogenous material is buried under sand and gravel 2-5 cm deeper than common hypolithic biocrust it could preserve for a dramatically longer periods and have the 14C "age" up to 1100 yr BP. As evidenced by optical and scanning electron microscopy with EDX this old organogenous material of hypolithic origin still retains clear filamentous structure of cyanobacteria biofilm as well as remnants of EPS stabilized mainly by amorphous Si and Al

  17. CHEMICAL CLEANING OF NANOFILTRATION MEMBRANES FOULED BY ORGANIC MATTERS

    Directory of Open Access Journals (Sweden)

    CHARLENE C. H. KOO

    2016-07-01

    Full Text Available Membrane fouling is a term to describe non-integral substance on membrane surface which results in rapid decline of permeation flux and deteriorate the performance of membrane. Chemical cleaning agents especially like alkaline cleaners are most widely employed to restore the membrane performance. This research mainly investigated the potential use of sodium hydroxide (NaOH and sodium hypochlorite (NaOCl as the chemical cleaning agents to restore the permeate flux of organically fouled nanofiltration (NF membranes under varying applied pressure and flow condition. The performances of the cleaning protocols were quantified using flux recovery and resistance removal. The results demonstrated that NaOCl is more effective than NaOH. This observation is also in line with FTIR analysis in which the transmittance intensity showed by FTIR spectra of NaOCl is higher than that of NaOH. The results also reported that higher flux recovery and resistance removal were achieved when the fouled NF membranes were cleaned with higher concentration of chemical agents and applied pressure. However, the improvements of flux recovery and resistance removal by increasing the applied pressure were found insignificant at higher applied pressure range (16 to 18 bar than the lower applied pressure range (i.e. 12 to 14 bar. This research plays an important role by identifying the key parameters that could restore the flux of organically fouled NF membranes significantly.

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

    Science.gov (United States)

    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.

  19. Biological early diagenesis and insolation-paced paleoproductivity signified in deep core sediment organic matter.

    Science.gov (United States)

    Chen, Meilian; Kim, Ji-Hoon; Choi, Jiyoung; Lee, Yun Kyung; Hur, Jin

    2017-05-08

    The dynamics of a large stock of organic matter contained in deep sediments of marginal seas plays pivotal role in global carbon cycle, yet it is poorly constrained. Here, dissolved organic matter (DOM) in sediments was investigated for core sediment up to ~240 meters deep in the East/Japan Sea. The upper downcore profile (≤118 mbsf, or meters below seafloor) at a non-chimney site (U1) featured the exponential production of dissolved organic carbon (DOC) and optically active DOM with time in the pore water above sulfate-methane-transition-zone (SMTZ), concurrent with the increases of nutrients and alkalinity, and the reduction of sulfate. Such depth profiles signify a biological pathway of the DOM production during the early diagenesis of particulate organic matter presumably dominated by sulfate reduction. Below the SMTZ, an insolation-paced oscillation of DOM in a ~405-Kyr cycle of orbital eccentricity was observed at site U1, implying astronomically paced paleoproductivity stimulated by light availability. Furthermore, DOM dynamics of the deep sediments were likely governed by intensive humification as revealed by the less pronounced protein-like fluorescence and the lower H/C and O/C ratios below SMTZ among 15,281 formulas identified. Our findings here provide novel insights into organic matter dynamics in deep sediments.

  20. An invasive riparian tree reduces stream ecosystem efficiency via a recalcitrant organic matter subsidy.

    Science.gov (United States)

    Mineau, Madeleine M; Baxter, Golden V; Marcarelli, Amy M; Minshall, G Wayne

    2012-07-01

    A disturbance, such as species invasion, can alter the exchange of materials and organisms between ecosystems, with potential consequences for the function of both ecosystems. Russian olive (Elaeagnus angustifolia) is an exotic tree invading riparian corridors in the western United States, and may alter stream organic matter budgets by increasing allochthonous litter and by reducing light via shading, in turn decreasing in-stream primary production. We used a before-after invasion comparison spanning 35 years to show that Russian olive invasion increased allochthonous litter nearly 25-fold to an invaded vs. a control reach of a stream, and we found that this litter decayed more slowly than native willow. Despite a mean 50% increase in canopy cover by Russian olive and associated shading, there were no significant changes in gross primary production. Benthic organic matter storage increased fourfold after Russian olive invasion compared to pre-invasion conditions, but there were no associated changes in stream ecosystem respiration or organic matter export. Thus, estimated stream ecosystem efficiency (ratio of ecosystem respiration to organic matter input) decreased 14%. These findings show that invasions of nonnative plant species in terrestrial habitats can alter resource fluxes to streams with consequences for whole-ecosystem functions.

  1. The impact of vegetation on sedimentary organic matter composition and PAH desorption

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Elizabeth Guthrie [North Carolina State University, Department of Forestry and Environmental Resources, 2800 Faucette Drive, Raleigh, NC 27695 (United States)], E-mail: elizabeth_nichols@ncsu.edu; Gregory, Samuel T.; Musella, Jennifer S. [North Carolina State University, Department of Forestry and Environmental Resources, 2800 Faucette Drive, Raleigh, NC 27695 (United States)

    2008-12-15

    Relationships between sedimentary organic matter (SOM) composition and PAH desorption behavior were determined for vegetated and non-vegetated refinery distillate waste sediments. Sediments were fractionated into size, density, and humin fractions and analyzed for their organic matter content. Bulk sediment and humin fractions differed more in organic matter composition than size/density fractions. Vegetated humin and bulk sediments contained more polar organic carbon, black carbon, and modern (plant) carbon than non-vegetated sediment fractions. Desorption kinetics of phenanthrene, pyrene, chrysene, and C{sub 3}-phenanthrene/anthracenes from humin and bulk sediments were investigated using Tenax beads and a two-compartment, first-order kinetic model. PAH desorption from distillate waste sediments appeared to be controlled by the slow desorbing fractions of sediment; rate constants were similar to literature values for k{sub slow} and k{sub veryslow}. After several decades of plant colonization and growth (Phragmites australis), vegetated sediment fractions more extensively desorbed PAHs and had faster desorption kinetics than non-vegetated sediment fractions. - Plants alter sediment organic matter composition and PAH desorption behavior.

  2. Significance of organic matter in Eocene turbidite sediments (SE Pyrenees, Spain)

    Science.gov (United States)

    Caja, M. A.; Permanyer, A.

    2008-11-01

    Although turbidite deposits are classically considered to be good reservoir rocks for oil and gas, there are no reports concerning their source rock potential in the literature. The sediments from the Vallfogona Formation in the South-Eastern Pyrenees present numerous organic matter-rich levels interbedded in sandstones and coarse turbidite deposits. Two types of organic matter deposits were differentiated on the basis of organic geochemistry and petrography: type A and type B. Type A was deposited in a carbonate marine environment under hypersaline conditions as indicated mainly by even/odd n-alkane predominance, pristane and phytane ratio (Pr/Ph) 1. Type B was deposited in a more mud-rich marine environment evidenced by the predominance of odd n-alkane, Pr/Ph ≥ 1, Ts/Tm diasteranes. Turbidite facies can be regarded as an environment where organic matter sedimentation is heterogeneous in type and amount. This study suggests that turbidite deposits with interbedded organic matter-rich levels may act as a combined source reservoir system.

  3. The Changes in Guilin Paddy Soil Organic Matter and Rice Yield under Long-Term Fertilization

    Institute of Scientific and Technical Information of China (English)

    Qiuliang YU; Zheng TANG; Zhongfang LI; Chunlan CHEN; Xiaoxian TANG; Yanli LIN

    2016-01-01

    Rational fertilization is an important measure to increase crop yield and soil fertility. Through analysis,this paper aims to master the change characteristics of soil organic matter and rice yield under different fertilizer treatments,in order to provide an important reference for the sustainable use of soil and effective fertilization. Long-term( 19 years) rice crop rotation experiments in waterloggogenic paddy soil were conducted to investigate the change trend of crop grain yield and soil organic matter with time,reveal the dynamic characteristics and relationship between main fertility factors and crop yields using comparative analysis at three sites with conventional fertilization and non-fertilization in Guilin. The results showed that compared with previous years,the rice yield increased by 53% under the fertilization treatment and degreased by 66% under the control. Over the years,the average soil organic matter( SOM) content under fertilization treatment was 23% higher than under CK treatment. This indicates that chemical fertilizer and organic manure application can increase the rice yield and soil organic matter,and high rice yield can be attributed to the SOM increase.

  4. Organic matter heterogeneities in 2.72 Ga stromatolites: Alteration versus preservation by sulfur incorporation

    Science.gov (United States)

    Lepot, Kevin; Benzerara, Karim; Rividi, Nicolas; Cotte, Marine; Brown, Gordon E., Jr.; Philippot, Pascal

    2009-11-01

    The stromatolites of the weakly metamorphosed 2.72 Ga Tumbiana Formation present abundant organic globules that resemble in size, shape and distribution the microorganisms observed in modern stromatolites. In order to evaluate the significance of these cell-like organic materials, we characterized organic matter in-situ down to the nanoscale using a combination of Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), Raman microspectroscopy, scanning transmission X-ray microscopy (STXM) and transmission electron microscopy (TEM). These analyses revealed the occurrence of two distinct types of organic matter forming μm-scale textural and chemical heterogeneities distributed in distinct mineralogical laminae of the stromatolites. Type A organic matter, which is by far the most abundant, consists of sulfur-poor organic matter that is located in mud-type laminae at grain boundaries, mostly in association with silicate minerals. In contrast, Type B organic matter is rare and preserved as inclusions in the core of calcite grains forming laminates. It occurs as micrometer-sized cell-like globules containing variable amounts of organic sulfur likely in the form of thiophenes. Different scenarios may account for these compositional heterogeneities in the kerogen. Based on textural and compositional analogies with modern stromatolites, it is argued that Type B sulfur-rich globules may represent microbial cells protected by mineral encapsulation and selectively preserved through polymerization by early diagenetic sulfurization. In modern sediments, this reaction is fuelled by bacterial sulfate reduction (BSR). This metabolism has been widely considered as a major driver in modern stromatolites calcification and could thus have played an important role in the formation of the Tumbiana Formation stromatolites. In contrast, Type A sulfur-poor organic matter corresponds to either fossil extracellular polymer substances (EPS) or recondensed kerogen

  5. Effects of effluent organic matter characteristics on the removal of bulk organic matter and selected pharmaceutically active compounds during managed aquifer recharge: Column study

    Science.gov (United States)

    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.

  6. Impact of Urbanisation on Soil Organic Matter Content in chernozems in Vojvodina region

    Science.gov (United States)

    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.

  7. Interactions Between Prokaryotes and Dissolved Organic Matter in Marine Waters

    DEFF Research Database (Denmark)

    Traving, Sachia Jo

    the key to understanding the mechanisms controlling the cycling of DOM within marine waters. In the thesis presented here, the aim was to investigate the activity and composition of prokaryotes to determine their functional role in DOM utilization. The thesis incorporates a range of study systems...... organic bound carbon equal in size to atmospheric carbon dioxide. Prokaryotes mediate the fate of a large part of marine DOM, which is their principal source of energy and substrate. However, a large fraction is also left behind in the water column persisting for millennia, and prokaryotes may hold...... – ranging from bacterioplankton communities in seasonally variable coastal ecosystems, a manipulated pelagic food web, to a mathematical model of free-living prokaryotes and extracellular enzyme strategies. The results characterize links between community dynamics and function in prokaryotes, and emphasize...

  8. The microbe electric: conversion of organic matter to electricity.

    Science.gov (United States)

    Lovley, Derek R

    2008-12-01

    Broad application of microbial fuel cells will require substantial increases in current density. A better understanding of the microbiology of these systems may help. Recent studies have greatly expanded the range of microorganisms known to function either as electrode-reducing microorganisms at the anode or as electrode-oxidizing microorganisms at the cathode. Microorganisms that can completely oxidize organic compounds with an electrode serving as the sole electron acceptor are expected to be the primary contributors to power production. Several mechanisms for electron transfer to anodes have been proposed including: direct electron transfer via outer-surface c-type cytochromes, long-range electron transfer via microbial nanowires, electron flow through a conductive biofilm matrix containing cytochromes, and soluble electron shuttles. Which mechanisms are most important depend on the microorganisms and the thickness of the anode biofilm. Emerging systems biology approaches to the study, design, and evolution of microorganisms interacting with electrodes are expected to contribute to improved microbial fuel cells.

  9. Using thermal analysis to evaluate the fire effects on organic matter content of Andisols

    Directory of Open Access Journals (Sweden)

    J. Neris

    2013-09-01

    Full Text Available Soil organic compounds play a relevant role in aggregate stability and thus, in the susceptibility of soils to erosion. Thermal analysis (N2 and air and chemical oxidation techniques (dichromate and permanganate oxidation were used to evaluate the effects of a forest fire on the organic matter of Andisols. Both thermal analysis and chemical methods showed a decrease in the organic matter content and an increase in the recalcitrance of the remaining organic compounds in the burned zones. Thermal analysis indicated an increase in the thermal stability of the organic compounds of fire-affected soils and a lower content of both labile and recalcitrant pools as a consequence of the fire. However, this decrease was relatively higher in the labile pool and lower in the recalcitrant one, indicative of an increase in the recalcitrance of the remaining organic compounds. Apparently, black carbon did not burn under our experimental conditions. Under N2, the results showed a lower labile and a higher recalcitrant and refractory contents in burned and some unburned soils, possibly due to the lower decomposition rate under N2 flux. Thermal analysis using O2 and the chemical techniques showed a positive relation, but noticeable differences in the total amount of the labile pool. Thermal analysis methods provide direct quantitative information useful to characterize the soil organic matter quality and to evaluate the effects of fire on soils.

  10. Particulate organic matter in rivers of Fukushima: An unexpected carrier phase for radiocesiums.

    Science.gov (United States)

    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 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 lead to significant deliveries of bioavailable radiocesium for living organisms at Fukushima.

  11. Reduction of ferrihydrite with adsorbed and coprecipitated organic matter: microbial reduction by Geobacter bremensis vs. abiotic reduction by Na-dithionite

    Science.gov (United States)

    Eusterhues, K.; Hädrich, A.; Neidhardt, J.; Küsel, K.; Keller, T. F.; Jandt, K. D.; Totsche, K. U.

    2014-09-01

    Ferrihydrite is a widespread poorly crystalline Fe oxide which becomes easily coated by natural organic matter in the environment. This mineral-bound organic matter entirely changes the mineral surface properties and therefore the reactivity of the original mineral. Here, we investigated 2-line ferrihydrite, ferrihydrite with adsorbed organic matter, and ferrihydrite coprecipitated with organic matter for microbial and abiotic reduction of Fe(III). Ferrihydrite-organic matter associations with different organic matter loadings were reduced either by Geobacter bremensis or abiotically by Na-dithionite. Both types of experiments showed decreasing initial Fe-reduction rates and decreasing degrees of reduction with increasing amounts of mineral-bound organic matter. At similar organic matter loadings, coprecipitated ferrihydrites were more reactive than ferrihydrites with adsorbed organic matter. The difference can be explained by the smaller crystal size and poor crystallinity of such coprecipitates. At small organic matter loadings the poor crystallinity of coprecipitates led to even faster Fe-reduction rates than found for pure ferrihydrite. The amount of mineral-bound organic matter also affected the formation of secondary minerals: goethite was only found after reduction of organic matter-free ferrihydrite and siderite was only detected when ferrihydrites with relatively low amounts of mineral-bound organic matter were reduced. We conclude that direct contact of G. bremensis to the Fe oxide mineral surface was inhibited by attached organic matter. Consequently, mineral-bound organic matter shall be taken into account as a factor in slowing down reductive dissolution.

  12. Buried paleosols of the Upper Paleolithic multilayered site Kostenki-1

    Science.gov (United States)

    Aparin, B. F.; Platonova, N. I.; Sukhacheva, E. Yu.; Dudin, A. E.

    2016-12-01

    The morphology and chemical and physicochemical properties of paleosols buried at the Upper Paleolithic multilayered site Kostenki-1 in Kostenki-Borshchevo district of Voronezh oblast were studied. Four in situ paleosols formed 20-40(45) ka ago were separated in the archaeological excavation. Together with the surface soils, they characterized two different epochs of pedogenesis—the interstadial and interglacial (Holocene) epochs—and three shorter cycles of pedogenesis. The traces of human occupation in the studied hollow in the Late Paleolithic were found in the layers corresponding to the interstadial epoch. The buried paleosols had a simple horizonation: A(W)-C. A shallow thickness of the soil profiles could be due to relatively short periods of pedogenesis and to the shallow embedding by the carbonate geochemical barrier. The degree of the organic matter humification in the paleosols varied from 0.6 to 1.5, which corresponded to the mean duration of the period of biological activity of 60 to 150 days per year characterizing the climatic conditions of the tundra, taiga, forest-steppe, and steppe natural zones. In the excavation Kostenki-1 (2004-2005), soil-sediment sequences composed of five series of lithological layers with soil layers on top of them were found. Their deposition proceeded in two phases—the water phase and the aerial phase—that predetermined the morphology and composition of the soil-sediment sequences. The history of sediment accumulation in the studied hollow consisted of five stages. Similar morphologies and compositions of the soil-sediment sequences corresponding to these stages attest to the cyclic pattern of their development. The stages of sedimentation and soil formation corresponded to cyclic climate fluctuations with changes in the temperature and moisture conditions. A comparative analysis of the morphology and properties of the paleosols and soil-sediment sequences made it possible to characterize the environmental

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

    Science.gov (United States)

    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. Modeling the vertical soil organic matter profile using 210Pbex measurements and Bayesian inversion

    Directory of Open Access Journals (Sweden)

    B. Kruijt

    2011-07-01

    Full Text Available In view of its potential significance for soil organic matter (SOM cycling, the vertical SOM distribution in the profile should be considered in models. To mechanistically predict the SOM profile, three additional processes should be represented compared to bulk SOM models: (vertically distributed rhizodeposition, mixing due to bioturbation, and movement with the liquid phase as dissolved organic matter. However, the convolution of these processes complicates parameter estimation based on the vertical SOM distribution alone. Measurements of the atmospherically produced isotope 210Pbex may provide the additional information needed to constrain the processes. Since 210Pbex enters the soil at the surface and bind strongly to organic matter it is an effective tracer for SOM transport. In order to study the importance of root input, bioturbation, and liquid phase transport for SOM profile formation we performed Bayesian parameter estimation of the previously developed mechanistic SOM profile model SOMPROF. 13 parameters, related to decomposition and transport of organic matter, were estimated for the soils of two temperate forests with strongly contrasting SOM profiles: Loobos (the Netherlands and Hainich (Germany. Measurements of organic carbon stocks and concentrations, decomposition rates, and 210Pbex profiles were used in the optimization. For both sites, 3 optimizations were performed in which stepwise 210Pbex data and prior knowledge were added. The optimizations yielded posterior distributions with several cases (modes which were characterized by the dominant organic matter (OM pool: non-leachable slow OM, leachable slow OM, or root litter. For Loobos, the addition of 210Pbex data to the optimization clearly indicated which case was most likely. For Hainich, there is more uncertainty, but the most likely case produced by the optimization agrees well with other measurements. For both sites the most likely case of the final optimization was one

  15. Anammox for ammonia removal from pig manure effluents: Effect of organic matter content on process performance

    DEFF Research Database (Denmark)

    Salces, Beatriz Molinuevo; García, M. C.; Karakashev, Dimitar Borisov

    2009-01-01

    oxidation) diluted with synthetic wastewater. High ammonium removal was achieved, up to 92.1 +/- 4.9% for diluted UASB-post-digested effluent (95 mg COD L-1) and up to 98.5 +/- 0.8% for diluted partially oxidized effluent (121 mg COD L-1). Mass balance clearly showed that an increase in organic loading...... improved ammonium removal at high organic matter concentration. Up to threshold organic load concentration of 142 mg COD L-1 of UASB-post-digested effluent and 242 mg COD L-1 of partially oxidized effluent, no effect of organic loading on ammonia removal was registered (ammonium removal was above 80...

  16. Organic matter produced by algae and cyanobacteria: Quantitative and qualitative characterization

    Institute of Scientific and Technical Information of China (English)

    Maud Leloup; Rudy Nicolau; Virginie Pallier; Claude Yéprémian; Geneviève Feuillade-Cathalifaud

    2013-01-01

    This work aims at characterizing organic matter produced by an alga Euglena gracilis and a cyanobacteria Microcystis aeruginosa and assessing the evolution of its characteristics during growth.A culture medium was optimized.The species growth phases were monitored using both visible spectrophotometry and flow cytometry cell counting.Organic matter fractionation according to hydrophobicity and specific UV absorbance (SUVA) index were used to specifically characterize the produced algal organic matter (AOM).The AOM characteristics were both growth phase and species dependent.However,a similar evolution was observed.The hydrophilic fraction (HPI) was the major fraction whatever the growth phases and was almost the only one produced during lag and exponential phases.It represented around 75% of AOM during exponential phase and then decreased when the stationary phase appeared.It represented 46% and 60% of the AOM during late decline phase for the cyanobacteria and the alga respectively.The hydrophobic (HPO) and transphilic (TPH) fractions started to appear from the beginning of the stationary phase with more hydrophobic compounds coming from intracellular organic material of dying cells.HPO and TPH percentages still increased during the decline phase probably because of two additional processes:photo-dissolution and leaching of particulate organic matter from cells fragments.A comparison of AOM during late decline phase and natural organic matter (NOM) from Glane River (France) underlined that AOM was more hydrophilic and presented a lower SUVA for each fractions than NOM.However,the difference between NOM and AOM hydrophobicity narrowed during decline phase.

  17. Role of organic matter, clay, and iron contents in the sorption of oxytetracycline on river sediments

    Directory of Open Access Journals (Sweden)

    Mahmood Mahdi Barbooti

    2017-05-01

    Full Text Available Background: Oxytetracycline (OTC is a widely-used antibiotic; metabolism studies indicate only partial assimilation of it inside the body. Traditional wastewater treatment plants cannot remove OTC, and this results in the release of considerable amounts of the drug into aquatic environments. There is much concern over the role of residual antibiotics in the development of new generations of bacteria with modified resistance to the antibiotics. The present work investigated the possibility of OTC sorption on river sediments. Methods: Seven sediment samples were collected from various locations and depths of the Passaic River in New Jersey. The texture, clay, extractable iron, and organic matter contents of the sediments were determined. Pyrolysis-gas chromatography-mass spectrometric (Py GC-MS analysis indicated the presence of 3 categories of organic materials: petroleum hydrocarbons, anthropogenic, and plant residual materials. The sediment samples were equilibrated with OTC solutions for 24 hours followed by centrifugation and syringe filtration. The residual OTC contents were determined by high performance liquid chromatography. Results: It appeared that 35%-60% fractions of OTC were retained by the sediments. The sorption capacity values of the sediments were correlated with clay content, organic matter content, and available iron. A poor correlation was found between adsorption capacity and clay content in the presence of organic matter and iron. Meanwhile, a relatively strong correlation was found between adsorption capacity with the iron, R2 = 0.7499, and organic matter contents of the sediments, R2 = 0.7899. Thus, the sorption of OTC on sediments is governed by all constituents. Conclusion: It was concluded that the antibiotic-sediment interaction is controlled mainly by the organic matter and iron contents.

  18. Effect of aggregation on SOC transport: linking soil properties to sediment organic matter

    Science.gov (United States)

    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.

  19. Soil warming affects soil organic matter chemistry of all density fractions of a mountain forest soil

    Science.gov (United States)

    Schnecker, Jörg; Wanek, Wolfgang; Borken, Werner; Schindlbacher, Andreas

    2016-04-01

    Rising temperatures enhance microbial decomposition of soil organic matter (SOM) and increase thereby the soil CO2 efflux. Elevated microbial activity might differently affect distinct SOM pools, depending on their stability and accessibility. Soil fractions derived from density fractionation have been suggested to represent SOM pools with different turnover times and stability against microbial decomposition. We here investigated the chemical and isotopic composition of bulk soil and three different density fractions of forest soils from a long term warming experiment in the Austrian Alps. At the time of sampling the soils in this experiment had been warmed during the snow-free period for 8 consecutive years. During that time no thermal adaptation of the microbial community could be identified and CO2 release from the soil continued to be elevated by the warming treatment. Our results which included organic C content, total N content, δ13C, δ 14C, δ 15N and the chemical composition, identified by pyrolysis-GC/MS, showed no significant differences in bulk soil between warming treatment and control. The differences in the three individual fractions (free particulate organic matter, occluded particulate organic matter and mineral associated organic matter) were mostly small and the direction of warming induced change was variable with fraction and sampling depth. We did however find statistically significant effects of warming in all density fractions from 0-10 cm depth, 10-20 cm depth or both. Our results also including significant changes in the supposedly more stable mineral associated organic matter fraction where δ 13C values decreased at both sampling depths and the relative proportion of N-bearing compounds decreased at a sampling depth of 10-20 cm. All the observed changes can be attributed to an interplay of enhanced microbial decomposition of SOM and increased root litter input. This study suggests that soil warming destabilizes all density fractions of

  20. Effect of organic matter and Si liquid fertilizer on growth and yield of sugar cane

    Directory of Open Access Journals (Sweden)

    Djajadi Djajadi

    2017-02-01

    Full Text Available Sugarcane is known to absorb more Si than any other nutrient from the soil; therefore continuous cropping of the plant at the same soil would bring consequences of more Si and organic matter depletion. Silicon (Si is considered as a beneficial nutrient for sugarcane production while organic matter is well known as soil amendment. Field study was carried out to know the effect of organic and Si liquid fertilizer on growth, Si and N uptake, and yield of cane variety of PSBM 901. The study field was located at Kempleng village, Purwoasri, East Java and the study was done from May 2013 up to September 2014. Split plot design with three replicates was employed to arrange treatments. Organic matter types (no organic matter, Crotalaria juncea and manure were set as main plots while Si liquid fertilizer concentration (0, 15% Si and 30% S were arranged as sub plots. C juncea was planted at 15 days before planting of sugar cane, and after 35 days the C juncea were chopped and mixed into the soil. Manure was added one week before sugar cane was planted. Si liquid fertilizer was sprayed to the whole part of sugar cane plant at 30 and 50 days after sugar cane was planted. All treatments received basal fertilizer of 800 kg ZA/ha, 200 kg SP 36/ha and 300 kg KCl/ha. Results showed that interaction between organic matter and Si liquid fertilizer significantly affected on Si and N absorption, length of stem, yield and rendement of sugar cane. Addition of manure and followed by spraying of 30% Si liquid fertilizer gave the highest value of S and N absorption (869 g SiO2/plant and 720 g N/plant, cane yield (155.74 tons/ha and rendement (8.15%.

  1. Black carbon contributes to organic matter in young soils in the Morteratsch proglacial area (Switzerland

    Directory of Open Access Journals (Sweden)

    E. Eckmeier

    2013-03-01

    Full Text Available Most glacier forefields of the European Alps are being progressively exposed since the glaciers reached their maximum expansion in the 1850s. Global warming and climate changes additionally promote the exposure of sediments in previously glaciated areas. In these proglacial areas, initial soils have started to develop so that they may offer a continuous chronosequence from 0 to 150-yr-old soils. The build-up of organic matter is an important factor of soil formation, and not only autochthonous but also distant sources might contribute to its accumulation in young soils and surfaces of glacier forefields. Only little is known about black carbon in soils that develop in glacier forefields, although charred organic matter could be an important component of organic carbon in Alpine soils. The aim of our study was to examine whether black carbon (BC is present in the initial soils of a proglacial area, and to estimate its relative contribution to soil organic matter. We investigated soil samples from 35 sites distributed over the whole proglacial area of Morteratsch (Upper Engadine, Switzerland, covering a chronosequence from 0 to 150 yr. BC concentrations were determined in fine earth using the benzene polycarboxylic acid (BPCA marker method. We found that charred organic matter occurred in the whole area, and that it was a main compound of soil organic matter in the youngest soils, where total Corg concentrations were very low. The absolute concentrations of BC in fine earth were generally low but increased in soils that had been exposed for more than 40 yr. Specific initial microbial communities may profit from this additional C source during the first years of soil evolution and potentially promote soil development in its early stage.

  2. Spectrophotometry and organic matter on Iapetus. 1: Composition models

    Science.gov (United States)

    Wilson, Peter D.; Sagan, Carl

    1995-01-01

    Iapetus shows a greater hemispheric albedo asymmetry than any other body in the solar system. Hapke scattering theory and optical constants measured in the laboratory are used to identify possible compositions for the dark material on the leading hemisphere of Iapetus. The materials considered are poly-HCN, kerogen, Murchison organic residue, Titan tholin, ice tholin, and water ice. Three-component mixtures of these materials are modeled in intraparticle mixture of 25% poly-HCN, 10% Murchison residue, and 65% water ice is found to best fit the spectrum, albedo, and phase behavior of the dark material. The Murchison residue and/or water ice can be replaced by kerogen and ice tholin, respectively, and still produce very good fits. Areal and particle mixtures of poly-HCN, Titan tholin, and either ice tholin or Murchison residue are also possible models. Poly-HCN is a necessary component in almost all good models. The presence of poly-HCN can be further tested by high-resolution observations near 4.5 micrometers.

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

    Science.gov (United States)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Black carbon (BC) in ultrafiltered high-molecular-weight DOM (UDOM) was measured in surface waters of Delaware Bay, Chesapeake Bay and the adjacent Atlantic Ocean (USA) to ascertain the importance of riverine and estuarine DOM as a source of BC to the ocean. BC comprised 5-72% of UDOM-C (27+/-l7%) and on average 8.9+/-6.5% of dissolved organic carbon (DOC) with higher values in the turbid region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of Delaware Bay suggest that the higher levels of BC in surface water UDOM originated from localized sources, possibly from atmospheric deposition or released from resuspended sediments. Black carbon comprised 4 to 7% of the DOC in the coastal Atlantic Ocean, revealing that river-estuary systems are important exporters of colloidal BC to the ocean. The annual flux of BC from Delaware Bay UDOM to the Atlantic Ocean was estimated at 2.4x10(exp 10) g BC yr(exp -1). The global river flux of BC through DOM to the ocean could be on the order of 5.5x1O(exp 12)g BC yr (exp -1). These results support the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition.

  4. Processes and modeling of hydrolysis of particulate organic matter in aerobic wastewater tratment - A review

    DEFF Research Database (Denmark)

    Morgenroth, Eberhard Friedrich; Kommedal, Roald; Harremoës, Poul

    2002-01-01

    Carbon cycling and the availability of organic carbon for nutrient removal processes are in most wastewater treatment systems restricted by the rate of hydrolysis of slowly biodegradable (particulate) organic matter. To date, the mechanisms of hydrolysis are not well understood for complex...... substrates and mixed populations. Most mathematical models use a simple one-step process to describe hydrolysis. In this article, mechanisms of hydrolysis and mathematical models to describe these processes in wastewater treatment processes are reviewed. Experimental techniques to determine mechanisms...

  5. Microbial diversity and organic matter fractions under two arid soils in Algerian Sahara

    Science.gov (United States)

    Karabi, Mokhtar; Hamdi, Aissa Baelhadj; Zenkhri, Salah

    2016-07-01

    The Algerian Sahara is characterized by a heterogeneity of edaphic conditions and climatic dissimilarities; however, information on biological indicators of arid soils is weakly documented in this area. The researchers who have studied the biological activities of the soils of the arid regions have underlined their low organic matter content, particularly their very low rates of organic nitrogen; a low humification because seriously inhibited by a significant mineralization. The objective of the current work is to study the microbial biomass densities and organic matter fractions for different types of soil, under two arid soil in Algerian Sahara. The experiment was conducted in an alluvial soil in traditional palm grove of Guerrara, and in a saline soil in experimental field of university of Ouargla. Composite soil samples (10 subsamples each) were collected aseptically at 0-20 cm depth on two diagonal transects drawn over an area of 12 ha. The following germs densities were determined: Bacteria, Fungi and Actinomycetes. The soil organic matter fractions, the textural fractions, chemical attributes (organic C, total N, total limestone and gypsum) were also determined. The microbial groups count on both soils reveals that the bacterianmicroflora present a numerical superiority followed by the actinomycetes and finally fungi. The micro-organisms densities except fungal density, showed a prevalence of the bacterianmicroflora, and actinomycetes in alluvial soil compared to saline soil. Fractionation of soil organic matter show that all fractions are better represented in alluvial soil except non-extractable organic carbon (NEOC) which are better represented in saline soil. This confirms that alluvial soil has a relatively large biological activity than saline soil and that humification process is relatively pronounced by comparing it with the saline soil, which tends to contain little polycondenseshumic compounds.

  6. Tracing organic matter composition and distribution and its role on arsenic release in shallow Cambodian groundwaters

    Science.gov (United States)

    Lawson, Michael; Polya, David A.; Boyce, Adrian J.; Bryant, Charlotte; Ballentine, Christopher J.

    2016-04-01

    Biogeochemical processes that utilize dissolved organic carbon are widely thought to be responsible for the liberation of arsenic from sediments to shallow groundwater in south and southeast Asia. The accumulation of this known carcinogen to hazardously high concentrations has occurred in the primary source of drinking water in large parts of densely populated countries in this region. Both surface and sedimentary sources of organic matter have been suggested to contribute dissolved organic carbon in these aquifers. However, identification of the source of organic carbon responsible for driving arsenic release remains enigmatic and even controversial. Here, we provide the most extensive interrogation to date of the isotopic signature of ground and surface waters at a known arsenic hotspot in Cambodia. We present tritium and radiocarbon data that demonstrates that recharge through ponds and/or clay windows can transport young, surface derived organic matter into groundwater to depths of 44 m under natural flow conditions. Young organic matter dominates the dissolved organic carbon pool in groundwater that is in close proximity to these surface water sources and we suggest this is likely a regional relationship. In locations distal to surface water contact, dissolved organic carbon represents a mixture of both young surface and older sedimentary derived organic matter. Ground-surface water interaction therefore strongly influences the average dissolved organic carbon age and how this is distributed spatially across the field site. Arsenic mobilization rates appear to be controlled by the age of dissolved organic matter present in these groundwaters. Arsenic concentrations in shallow groundwaters (20 m) groundwaters. We suggest that, while the rate of arsenic release is greatest in shallow aquifer sediments, arsenic release also occurs in deeper aquifer sediments and as such remains an important process in controlling the spatial distribution of arsenic in the

  7. Exploratory analysis of excitation-emission matrix fluorescence spectra with self-organizing maps as a basis for determination of organic matter removal efficiency at water treatment works

    Science.gov (United States)

    Bieroza, Magdalena; Baker, Andy; Bridgeman, John

    2009-12-01

    In the paper, the self-organizing map (SOM) was employed for the exploratory analysis of fluorescence excitation-emission data characterizing organic matter removal efficiency at 16 water treatment works in the UK. Fluorescence spectroscopy was used to assess organic matter removal efficiency between raw and partially treated (clarified) water to provide an indication of the potential for disinfection by-products formation. Fluorescence spectroscopy was utilized to evaluate quantitative and qualitative properties of organic matter removal. However, the substantial amount of fluorescence data generated impeded the interpretation process. Therefore a robust SOM technique was used to examine the fluorescence data and to reveal patterns in data distribution and correlations between organic matter properties and fluorescence variables. It was found that the SOM provided a good discrimination between water treatment sites on the base of spectral properties of organic matter. The distances between the units of the SOM map were indicative of the similarity of the fluorescence samples and thus demonstrated the relative changes in organic matter content between raw and clarified water. The higher efficiency of organic matter removal was demonstrated for the larger distances between raw and clarified samples on the map. It was also shown that organic matter removal was highly dependent on the raw water fluorescence properties, with higher efficiencies for higher emission wavelengths in visible and UV humic-like fluorescence centers.