Changes In Organic Composition Research Articles

Substance flow analysis on the leachate DOM molecules along five typical membrane advanced treatment processes

The processes combining biological treatment with membrane separation technologies have been widely adopted for leachate treatment. However, dissolved organic matter (DOM) of leachate membrane concentrates generated from various membrane separation technologies has not been systematically investigated in field scale. Therefore, substance flow analysis based on DOM molecular information of leachate membrane concentrates from primary membrane systems (i.e. nanofiltration (NF) and reverse osmosis (RO)) and secondary membrane systems (i.e. disk-tube reverse osmosis (DTRO) and humic substance filtration system (HSF)) in five engineering-scale leachate treatment facilities, obtained via ultra-performance liquid chromatography coupled with hybrid quadrupole Orbitrap mass spectrometry, was given and simultaneously compared. In NF concentrates (NFC), 45.1–98.5% of DOM originated from raw leachate (L-DOM) was concentrated, showing poor biodegradability. The L-DOM interception characteristics of NFC-fed HSF were mainly based on volume reduction but concentration effect. L-DOM in RO concentrates (ROC) showed a higher proportion of peak intensity reduced components, accounting for 50.3–96.8%, and organic composition changes were more dependent on water quality characteristics than membrane types. ROC-fed DTRO intercepted 49.3–72.6% of L-DOM, but DTRO may be less effective at intercepting DOM molecules in landfill leachate with higher oxidation levels. Considering risks from feasible treatment technologies, the difficulty for the treatment of leachate membrane concentrates followed the order of DTRO concentrates > ROC > NFC. This study suggests that ROC-fed DTRO need to be controlled to avoid amplifying the treatment difficulty. Besides, treatment technologies for RO and DTRO concentrates with low-concentrated but refractory DOM and high salts should be explored.

Organic chemistry insights for the exceptional soil carbon storage of the seagrass Posidonia australis

The high organic carbon (OC) stores in seagrass meadows have led to their recognition as significant Blue Carbon sinks, though the diagenetic conditions that enable OC retention in seagrass soils remain poorly understood. In this study, seagrass soils were sampled from a Posidonia australis meadow in Oyster Harbour (Albany; south-western Australia) to investigate the preservation of sedimentary OC. We analysed soil characteristics (colour, grain size and redox potential), radiocarbon age, and characterised the soil organic matter (OM) using solid state CP/MAS 13C NMR spectroscopy to examine the preservation of OM down the soil profile. There was minimal change in organic composition over 1,700 years of accumulation, indicating long-term OM preservation. Primarily, this preservation appears to be driven by the recalcitrance of seagrass detritus buried in anoxic soils. The majority (70–83%) of total sedimentary OM comprised components directly attributable to seagrass origins (lignin, carbohydrate and black carbon-like matter), while the remainder consisted mostly of protein, some of which may have been present in seagrass biomass, along with likely contributions from algae and microbes. Although black carbon originates from organic matter combustion, here we provide evidence that the 13C NMR signal identified as black carbon-like matter in our soils is possibly associated with seagrass-derived organic matter consisting of degraded lignin products or other non-pyrogenic aromatics. The increase in the relative abundance of this black carbon-like matter with aging suggests its selective preservation. The relative abundances of carbohydrates significantly decreased with age down core (i.e. they appeared to be selectively decomposed), while lignin and protein did not show any quantitative changes in relative abundance (non-selective preservation). These findings demonstrate the exceptional preservation of P. australis derived OC, which contributes to our understanding of the higher OC storage capacity of Posidonia compared to other seagrass species.

Characterization of organic compounds from hydrogen peroxide-treated subbituminous coal and their composition changes during microbial methanogenesis

Natural gas burns cleaner than coal by reducing ∼50% of the carbon footprint and emission of toxic substances and particulates. Coalbed natural gas can be produced from coal by indigenous microorganisms. Hydrogen peroxide treatment to coal has been shown to enhance the production of biogenic coalbed natural gas. In this study, we investigated methane generation from a subbituminous coal pretreated by hydrogen peroxide and the changes of the organic composition during gas production. We demonstrate that there is a great potential to produce natural gas from hydrogen peroxide-treated coal by microorganisms. The organic composition of the coal-derived compounds and the bulk organic profiling were changed because of the microbial degradation. The liquid samples before and after gas production were characterized by fluorescence spectrometer, GC/MS, HPLC, GPC, and TOCs. The results indicated that the chemical treatment has produced both labile organic components and compounds that are recalcitrant to microbial degradation. Labile compounds including short-chain carboxylic acids (C1 to C6) were found to contribute to the gas production. HPSEC analysis has shown shifts of molecular weight distributions, confirming organic composition changes. In addition, the analyses suggested that the labile organic compounds were conducive to shorten the lag phase of the gas production, whereas the presumed-recalcitrant constituents were surprisingly slightly biodegraded. The analysis also showed that the chemical treatment and biotransformation could produce compounds that are toxic to the environment. Environmental impacts should be fully evaluated before field applications.

In situ characterization of change in superficial organic components of thermoacidophilic archaeon Acidianus manzaensis YN-25

For the first time, synchrotron radiation (SR) -based carbon K-edge X-ray absorption near edge structure (XANES) spectroscopy in-situ characterization was conducted to evaluate the evolution of superficial (about 10 nm) organic components of extracellular polymeric substances (EPS) of thermoacidophilic archaeon Acidianus manzaensis YN-25 acclimated with different energy substrates (FeS2, CuFeS2, S0, FeSO4). The atomic force microscopy (AFM) morphology scanning showed that the strain acclimated with different energy substrates varied a lot in EPS amount. XANES results showed clear associations between the energy substrates and the changes in organic composition in terms of typical function groups (CO, CO and CN). The chalcopyrite- and pyrite-acclimated cells contained higher proportion of proteins but less proportion of polysaccharides than the S0-acclimated cells. The FeSO4-acclimated cells contained the highest proportion of proteins, while the S0-acclimated cells contained more lipids and polysaccharides. The results of linear-combination and peak fitting of the K-edge XANES for the extracellular superficial organic component C is consistent with the trend in comparison with the results of FTIR and spectrophotometric determination, but there are significant differences in the values. These differences are caused by the inconsistencies of measurement depth between XANES and the latter two characterization methods.

<i>In Situ</i> Characterization of Superficial Organic Composition Changes of Thermoacidophilic Archaea <i>Acidianus manzaensis</i> YN-25 in Response to Energy Substrate

The differences of superficial (about 10 nm) extracellular polymeric substances (EPS) composition of thermoacidophilic archaea Acidianus manzaensis YN-25 acclimated with different energy substrates (FeS2, CuFeS2, S0, FeSO4) were analyzed in situ for the first time by synchrotron radiation (SR) based carbon K-edge X-ray absorption near edge structure (XANES) spectroscopy. The results showed that there are clear associations between the energy substrates and the changes in organic composition in terms of typical function groups (-C=O, -C-O and -C-N). The archaea acclimated with chalcopyrite and pyrite contain higher proportion of proteins but less polysaccharides compared to cells acclimated with S0.The archaea acclimated with FeSO4 contains the highest proportion of protein which is positively associated with the iron oxidation process, while archaea acclimated with S0 contains more lipids and polysaccharides, which may be favorable to the hydrophobic S0 adsorption and utilization processes.

Inorganic arsenic removal in rice bran by percolating cooking water

Rice bran, a by-product of milling rice, is highly nutritious but contains very high levels of the non-threshold carcinogen inorganic arsenic (i-As), at concentrations around 1mg/kg. This i-As content needs to be reduced to make rice bran a useful food ingredient. Evaluated here is a novel approach to minimizing rice bran i-As content which is also suitable for its stabilization namely, cooking bran in percolating arsenic-free boiling water. Up to 96% of i-As removal was observed for a range of rice bran products, with i-As removal related to the volume of cooking water used. This process reduced the copper, potassium, and phosphorus content, but had little effect on other trace- and macro-nutrient elements in the rice bran. There was little change in organic composition, as assayed by NIR, except for a decrease in the soluble sugar and an increase, due to biomass loss, in dietary fiber.

Flocculation performance of cationic polyacrylamide with high cationic degree in humic acid synthetic water treatment and effect of kaolin particles

Abstract In current research, the flocculation performance of cationic polyacrylamide flocculant PAMC with high cationic degree was investigated in HA synthetic water treatment, and the effect of kaolin particles was studied in kaolin-HA flocculation. Influencing factors, such as pH, PAMC dosage, initial HA concentration, cationic degree, stirring speed and stirring time, were investigated and optimized for HA removal efficiency. Two-dimensional fractal dimension of the flocs was analyzed based on flocs images, and FTIR analysis was accomplished to understand chemical structures of the flocs. Three-dimensional excitation emission matrix spectra was measured to analyze the changes in organic composition and concentraion. Finally, the HA and kaolin-HA synthetic water flocculation mechanism were studied and summarized based on analysis of zeta potential and pH. The results showed that 80.7% and 91.2% of HA removal efficiency was achieved in HA and kaolin-HA flocculation process by using 12.5 mg/L and 4–6 mg/L of PAMC, respectively. Moreover, partial colloidal HA was absorbed by kaolin particles before flocculation and was removed in flocculation through synergetic effect from kaolin particles. Charge neutralization and bridging effect was confirmed to be dominant in acidic and alkaline environment, respectively.

Decomposition and change in N and organic composition of small-diameter Douglas-fir woody debris over 23 years

Managing second-growth forests for multiple benefits requires enhanced information on decomposition of woody debris generated during forestry operations. Experimental thinning and biomass sampling at the Shawnigan Lake Research Forest on southern Vancouver Island facilitated retrospective sampling of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) stem sections (4.9–21.5 cm diameter) from 0 to 23 years after cutting. A sigmoidal pattern of density loss was observed, while a single-exponential fit gave a decay rate (k) of 0.058 year–1. Initial N concentrations were higher in bark than in sapwood and heartwood, and all increased during decay, while C/N ratios declined to around 175 for wood and 70 for bark. Nitrogen contents initially increased but tended to decline after about 50% C loss. Solid-state 13C nuclear magnetic resonance spectroscopy showed little change in organic composition, consistent with white-rot fungal decay, with only a few 19-year samples showing large increases in lignin typical of extensive brown-rot decay. Hydrolyzable monosaccharides of wood and bark were dominated by glucose followed by mannose, xylose, galactose, and arabinose. For wood, the mole fraction of mannose decreased with decomposition, whereas those of glucose, arabinose, and galactose increased slightly and that of xylose remained constant for both brown and white rot. Our results support indications that decomposition of smaller diameter woody debris from managed conifer forests will likely be dominated by white-rot fungi, leaving residues high in cellulose rather than in lignin.

Chemical Changes During 6 Years of Decomposition of 11 Litters in Some Canadian Forest Sites. Part 2. 13C Abundance, Solid-State 13C NMR Spectroscopy and the Meaning of “Lignin”

There is still a poor understanding of how changes in the organic composition of litter contribute to slowing or even cessation of decomposition. Using 13C nuclear magnetic resonance (NMR) spectroscopy of samples from the Canadian Intersite Decomposition Experiment (CIDET), we asked whether increasing lignin per se could account for the well-known increase in acid-unhydrolyzable residue (AUR), and secondly, using three litters from four sites with different mean annual temperatures, whether changes in organic composition would follow similar trajectories with C mass loss. At 6 years, there was 16–39% C remaining for 10 foliar litters and wood blocks at a site with rapid initial decomposition, and higher amounts remaining for three species at three colder sites. 13C NMR spectra obtained with rapid cross-polarization (CP) mainly showed increasing similarity among the foliar litters, although wood showed little change in composition. Foliage generally showed loss of O- and di-O-alkyl C, mainly from carbohydrate, and increase in alkyl, aromatic, phenolic and carboxyl C. However, O-alkyl C loss was limited, especially for litters with slow initial decomposition, and many litters showed relatively small changes in intensity distribution. Quantitative 13C (“BD”) spectra showed similar trends, but even smaller changes in C composition, and 6-year CP difference spectra showed that C was lost across the whole range of structures. Changes in δ13C were small and variable, but could be correlated to some extent with loss of carbohydrates versus tannins. Lignin was not selectively preserved, and the increase of resistant structures derived from lignin, tannins, and cutin collectively accounts for increasing AUR. Compositional changes of NMR C fractions across sites with different temperatures were small and inconsistent, likely due to the influence of other site factors; however, changes in their contents did largely follow consistent trajectories with %C remaining.

Implication of the compositional diversity of the soluble organic matrices of carbonate skeletons

Abstract The soluble organic matrices were extracted from carbonated shells of molluscs and a Scleractinia. The composition was analysed with UV spectrometry, HPLC with a dual detection and 2D electrophoresis. Few data are available on such components. However, the obtained results confirm the previous data: quantities but also properties of the matrices are characteristic of the taxa. Proteins/sugars ratios, molecular weights and acidities differ in all the studied samples. The diagenetic changes are different for different species. In a multilayered shell, each layer has a particular diagenetic evolution. Thus, some biases are induced in the faunal statistics used in palaeoecological studies. After the death of the animal, the rates of degradation of the skeletons are different. The soluble organic matrices are more or less rapidly dispersed in sea water, depending on the resistance of the skeletons. From this point of view, fragile shells contribute largely to the organic composition changes of surrounding water. The faunal composition and the biochemical characteristics of the skeletons are important for the evolution of the marine environment. Their soluble organic matrices are dispersed in the water and sediments, and their strong acidity plays a major role in the precipitation of carbonates. Moreover, these invisible matrices are permanently recycled in sedimentary processes.

Decomposition of plant residues used in no-tillage systems as revealed by flash pyrolysis

Changes in organic composition of crop residues (soybean, radish, white lupine, blue lupine, black oat and mucuna) that are utilized in crop rotations in no-tillage farming systems in the southern part of Brazil were evaluated by analytical flash pyrolysis. The pyrolysis allowed the identification of five groups of compounds in the residues: guaiacyl moieties in lignin (Lg), syringyl moities in lignin (Ls), polysaccharide (Ps), chlorophyll (Chl) and fatty acid (Fa) derivatives. The decomposition rates of the plant residues ranged from 4.7 to 5.9 g kg −1 day −1, with a mean value of 5.2 g kg −1 day −1, corresponding to a mean loss of 41% (37–47%) of the initial biomass after 80 days of incubation. The Ps and lignin contents were strongly affected by incubation; relative lignin content increased at the expense of polysaccharide derivatives. In the original samples, Ps was the principal group of organic compounds in green manure plant materials, with maximum values in blue and white lupine (67%); after incubation, Ps fractions decreased by 26–51% (average 40%), with the greatest value observed with mucuna and the lowest in white lupine. In soybean plant material the Ps fraction decreased only by 9%. Greater increases in relative lignin content were observed with Ls (156%) than with Lg (59%) derivatives, demonstrating that guaiacyl moieties are easier to biochemically degrade than syringyl moieties. A significant correlation between residue-weight loss and organic groups after 80 days incubation was only found with Ls. Plant materials showing a higher content of syringyl moieties after decomposition might aid in increasing soil organic matter. Flash pyrolysis was shown to be an adequate technique to follow the process of transformation of plant residues into stabilized soil organic matter.

Biomarkers as organic-carbon-source and environmental indicators in the Late Quaternary Arctic Ocean: problems and perspectives

In order to examine the variation in marine and terrigenous sources of the organic matter during the last 15,000 Cal. yr BP, hydrogen index values, C/N ratios, and specific biomolecules (short- and long-chain n -alkanes, short-chain fatty acids, sterols, alkenones , and pigments) were determined in three sediment cores from the Laptev Sea continental margin . The results show that the interpretation of the biomarker data is much more complicated and less definitive in comparison to similar data sets from low-latitude open-ocean environments. This is mainly caused by the complexity of the Arctic Ocean system, which is characterized by a high seasonality of sea-ice cover and primary productivity, sea-ice sediment transport and a high fluvial supply of freshwater (aquatic) organic matter. A combination of organic geochemical, organic petrographic and micropaleontological data may yield to a more precise identification of organic-carbon sources for these complex systems. On the Laptev Sea shelf (cores KD9502-14 and PS2725-5), terrigenous organic-carbon input controlled by river discharge seems to be predominant during the last about 10,000 Cal. yr BP. Maximum supply of terrigenous organic carbon was reached in the Early Holocene (i.e., about 9000–10,000 Cal. yr BP). Further offshore at the upper continental slope (core PS2458-4), a major change in organic-composition occurred near 10,000 Cal. yr BP. During this period hydrogen indices as well as the amounts of short-chain n -alkanes, short-chain fatty acids, dinosterol and brassicasterol significantly increased, indicating increased relative proportions of marine organic matter preserved in the later time interval.

Subaerial weathering of sedimentary organic matter

Small diameter core samples were taken from outcrops of the Permian Phosphoria Formation and the Cretaceous Pierre Shale of the Western United States to determine the effects of weathering on organic matter in shale outcrops. While the Pierre Shale core showed no evidence of weathering, the Phosphoria Formation showed significant reduction of overall organic content and pronounced changes in organic composition over the near-surface interval of the core. Total organic carbon is lower by as much as 60% over the upper 2 ft of the core. Chloroform-soluble organic matter and total hydrocarbon (C 15+) concentrations are 50% lower over this same interval. The ratio of saturated to aromatic hydrocarbons decreases steadily with core depth over the upper 2.6 ft of the core. Aromatic hydrocarbons are enriched in the stable carbon-13 isotope by an average of 1.7%. over this same interval. Shallow core samples also show a loss of n-paraffins relative to branched/cyclic compounds in the saturated C 15+ fraction. Although the extent of weathering is variable, certain characteristic effects are recognizable and can be applied to the interpretation of outcrop data in organic geochemical studies.

Effects of Starvation on Body Protein Utilization of Bluegill Sunfish (Lepomis macrochirus Rafinesque) with a Calculation of Caloric Requirements

Abstract Nitrogen excretion rates were measured for bluegill sunfish (Lepomis macrochirus) starved for periods of 7, 14, 21, and 28 days, and for glucose-fed controls. The starved fish had lower nitrogen excretion rates than controls, but there was no significant difference between average nitrogen excretion rates of starved fish from the four experimental periods. Body composition was analyzed. Protein and fat content decreased with starvation but ash content remained unchanged when compared to controls. The caloric requirement for starved bluegills was calculated on the basis of the change in organic composition of the body.

Evolution of Chazyan (Ordovician) Reefs of Eastern United States and Canada: ABSTRACT

Chazyan (lower middle Ordovician) reefs from the Virginias, Vermont and New York, and Quebec show changes in organic composition through time. In the evolution of reef communities, these Chazyan reefs represent assemblages or organisms which are transitional in taxonomic composition and ecologic setting between pre-Chazyan and Silurian reefs. Early Chazyan trepostome (Batostoma) and cyclostome (Cheiloporella) bryozoans built linearly aligned reefs up to 10 feet high in shallow, agitated waters. The reef matrix of carbonate mud and skeletal debris differs markedly from the cross-bedded, mud-free skeletal carbonates adjacent to the reefs. Middle Chazyan reefs shown an evolution of reef assemblages from a laminar stromatoporoid (Cystostroma)--algal (Anthracoporella) composition to an assemblage with a higher percentage of tabulate corals (Billingsaria), sponges (Zittelella), and a different stromatoporoid (Pseudostylodictyon). At the top of the Middle Chazyan, three separate assemblages (stromatolite-calcareous alga-nautiloid, trepostome and cyclostome bryozoans, and stromatoporoid-sponge-coral) are all in close lateral contact with each other and appear to have been contemporaneous. In the Upper Chazyan, the trepostome bryozoans replace the stromatoporoids of the early assemblages and combine with the alga (Anthracoporella) to form a different assemblage. This succession of assemblages takes place with no apparent chan e in habitat. The Lower Chazyan bryozoan reefs contain more detrital quartz and have more pronounced cross-bedding in adjacent sediments than the younger Chazyan reefs, indicating that the bryozoans existed in more agitated conditions closer to land than the later assemblages. However, close proximity of oolitic and oncolitic carbonates, dislodged and tumbled corals and stromatoporoids, erosional channels and margins cut into the reefs, and the presence of blue, green, and red algae suggest that the Middle and Upper Chazyan reefs also developed in shallow water. A spectrum of textures in the non-reef sediments, mudstones through well washed grainstones, represents most stages from restricted to open circulation, high energy conditions in their environments of deposition. The sequence of diagenetic events that affected the limestones is: formation of rim cement in grainstones before and concomitant with pore-filling drusy cementation, dolomitization, lithification of carbonate mud, and finally grain growth in the aragonite skeletons and carbonate mud. End_of_Article - Last_Page 542------------

UNEMPLOYMENT RELIEF WORK IN JAPAN

It is widely known that capitalistic accumulation or the development of productivity causes, through the process of high change in organic composition of the capital, relative surplus population or the unemployed labourers. Its inevitability can be explained by the law of disproportion in the capitalistic production. The labourers are at once attracted on the one hand and on the other repelled. In other words, employment and unemployment occur at the same time in the various enterprises of productive branches, and thus in the society as a whole relative surplus population or the unemployed labourers always exist and increase. Relative surplus population is thus the result of capitalistic accumulation and also a necessary condition for its development. The existence of the unemployed labourers plays a part of a lever for capitalistic accumulation. The fact has two aspects. In the first place, Capitalist production can by no means content itself with the quantity of disposable labour-power which the natural increase of population yields. It requires for its free play an industrial reserve army independent of these natural limits.'n) The unemployed are exactly what Marx called the human material always ready for use being independently of the limits of actual increase of population 2) and mean the existence of freely disposable labour power under the absolute control of the capital. Therefore, when the capital requires a greater amount of labour at the prosperous phase of economic cycle, relative surplus population answers that demand and supplies with labour power. The unemployed are produced as a result of multiplying in value of the capital in the process of progress of organic composition of the capital with disproportioned development, while the same factor causes them to function as a source of necessary additional labour power. Secondly, the existence of the unemployed lowers the various conditions

Stratigraphic Change in Organic Composition Demonstrated by Oil Specific Gravity-Depth Correlation in Tertiary Green River Oil Shales, Colorado

Specific gravity of oil retorted from oil shales of the Eocene Green River Formation, northwestern Colorado, decreases uniformly with increasing sample depth. Statistical evaluation of oil specific gravity-depth data from 18 sample sets representing 2,000 feet of the formation in an area of 325 square miles shows this correlation to be uniform stratigraphically and geographically. Mineral profiles did not correlate with this change. Decrease in oil specific gravity is associated with a progressive decrease in oxygen content of organic matter. This stratigraphic change probably resulted from the loss of carboxyl groups from the organic matter under heat and pressure of increasing depth of burial.