Showing papers in "Organic Geochemistry in 2004"

TL;DR: In this paper, the authors investigated the effect of 14 C-glucose addition on the mineralisation of charred maize and rye residues and oak wood (thermally altered at 800 C).

TL;DR: In this article, the surface properties of clay and metal oxide particles, and the electrified mineral-water interfaces play a major role in formation, structure and strength of aggregates, any surface modification, especially by polyanionic organic complexants such as humic substances, has a significant affect on particle interaction.

TL;DR: Turnover times for silage-maize cropped soil at steady state were on average 250 years for bulk SOC, 60 years for n-alkanes and 49 years for N-carboxylic acids as discussed by the authors.

TL;DR: It is shown that a variety of hopanoids occur in planctomycetes, including strictly anaerobic bacteria capable of anaerilic ammonium oxidation, which indicates that they may be an additional source for sedimentaryHopanoids.

TL;DR: In this paper, the authors evaluated the time dependence and efficacy of pretreatment by chemothermal oxidation for estimating black carbon (BC) content using 28 samples of wood char, soot, activated carbon, and sediment.

TL;DR: In this paper, the authors show that the rate of acetate decarboxylation is strongly pressure dependent with elevated pressure leading to a decreased rate of reaction, and that all organic breakdown processes that lead to a net volume increase, e.g. kerogen breakdown, will be relatively retarded in overpressured reservoirs.

TL;DR: Partially reversed order is common in gas samples from sedimentary basins in China, which can be attributed to one or several of the following mixing processes: mixing of biogenic and abiogenic gases; mixing of sapropelic and humic sourced gases; (c) mixing of gases from the same types of source rocks with different maturity; and (d) mixing gases from same source rock interval of varying maturity.

TL;DR: Ace Lake (Vestfold Hills, Antarctica) was initially a freshwater lake and then an open marine system, which is currently a meromictic basin with anoxic, sulfidic and methane-saturated bottom waters as discussed by the authors.

TL;DR: In this article, negative ion electrospray ionization (ESI) coupled with high field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is used to detect acidic NSO compounds in petroleum.

TL;DR: In this article, the authors examined the effect of oxic degradation and maturity on the TEX86 temperature proxy, and showed that oxic degrades did not appear to affect the tEX86 values within the analytical error.

TL;DR: In this paper, the adsorption selectivity for C 1 -C 6 hydrocarbons in a gas mixture on a variety of adsorbents was measured at 26 and 80°C at total pressures of 1, 2 and 3 atm.

TL;DR: Fulvic acids (6), humic acids (7) and natural organic matter (2) samples from the International Humic Substances Society Standards and Reference Collection were studied by total luminescence fluorescence spectroscopy (TLS) as mentioned in this paper.

TL;DR: In this article, a simple method for application in source potential mapping is used to assess the original oil and gas potentials in source rock horizons based upon Rock-Eval potential (S 2 ) and total organic carbon (TOC) values.

TL;DR: In this paper, a chemical oxidation method was used to remove lignin and then black carbon was estimated from solid-state 13C Nuclear Magnetic Resonance (NMR) spectroscopy, which may be a more accurate method for estimating black carbon in a range of natural organic matter samples from different environments.

TL;DR: In this paper, the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) has been studied in oil columns from the Liaohe basin, NE China, characterized by varied degrees of biodegradation.

TL;DR: It is reported that the ubiquitous soil mineral d-MnO2 significantly accelerated humification processes in a system containing glucose,glycine, and catechol, at temperatures and a pH typical of natural environments.

TL;DR: The mesopore protection hypothesis as discussed by the authors proposes that organic matter (OM) may be protected from enzymatic degradation by sequestration within mineral mesopores (2-50 nm diameter).

TL;DR: In this paper, the authors investigated the relationship between dissolved organic carbon (DOC) retention on mineral phase properties and the content of dithionite-extractable iron (Fed), specific surface area (SSA), and cation exchange capacity (CEC).

TL;DR: In this paper, hydrous pyrolysis experiments were conducted at 360°C for 72 h on Polish coals ranging in rank from lignite to semi-anthracite.

TL;DR: In this paper, the authors found that a wide range of autotrophic and heterotrophic microorganisms are involved and that anaplerotic reactions make a significant contribution in the transfer of the label into non-living soil organic matter.

TL;DR: It is hypothesized that degradation products (peptides) form high molecular mass fraction in deep water DOM, indicating that relatively fresh and large molecules become smaller in size along a degradation pathway.

TL;DR: A suite of petroleum reservoir extracts from the Liaohe basin, NE China, was analyzed to investigate the effects and controls of biodegradation on petroleum composition, seen as marked gradients in petroleum bulk composition, component concentrations and molecular indicators as discussed by the authors.

TL;DR: In this paper, soil lipids were investigated in three particle-size fractions of a forest soil, and the results indicated that different preservation mechanisms for lipids occur in this soil.

TL;DR: This paper measured the D/H ratios of terrestrially-sourced whole oils and their respective saturated, aromatic, and polar fractions, individual n-alkanes, formation waters and non-exchangeable hydrogen in kerogen in potential source rocks from seven Australian petroleum basins.

TL;DR: In this paper, a bulk humic acid (BHA) was extracted from Pahokee peat and was fractionated into eight fractions using an ultrafiltration apparatus with membranes having seven molecular cut-offs.

TL;DR: In this article, the elemental (concentration of organic carbon, atomic H/C and C/N ratios), isotopic ( δ 13 C values of organic matter) and molecular (predominant n -alkane chain length and carbon preference index (CPI)) organic components were measured for 600 samples taken from a 107m long core from the Padul Basin (Andalusia, Spain).

TL;DR: In this article, lipid biomarker distributions were used to assess changes in organic matter delivery and preservation processes in recent sediments of Lake Planina, a remote eutrophic lake situated in the Julian Alps, NW Slovenia.

TL;DR: The Corganic/Ntotal ratio and the hydrogen index (HI) are commonly used to describe the bulk composition, the sources and the post-depositional alteration of sedimentary organic matter as mentioned in this paper.

TL;DR: In this article, a reaction kinetic model is presented to differentiate individual complexes of reactions of the thermal decomposition of sedimentary organic matter during pyrolysis experiments, which is applied to methane generation from coal during open system pyrolys experiments with linear heating.

TL;DR: The results indicate that the acidic constituents in biodegraded oil are a product of the biodegradation, as the composition is very different from the non-biodegraded oils.