The biomolecular paleontology of continental fossils

Paleobiology ◽  
2000 ◽  
Vol 26 (S4) ◽  
pp. 169-193 ◽  
Author(s):  
Derek E. G. Briggs ◽  
Richard P. Evershed ◽  
Matthew J. Lockheart
Keyword(s):  
Organic Matter ◽  
Organic Material ◽  
Structural Changes ◽  
Environmental Data ◽  
Time Slice ◽  
Final Time ◽  
Biological Origin ◽  
Rapid Degradation ◽  
Substantial Modification ◽  
Living Organisms

The preservation of compounds of biological origin (nucleic acids, proteins, carbohydrates, lipids, and resistant biopolymers) in terrigenous fossils and the chemical and structural changes that they undergo during fossilization are discussed over three critical stratigraphic levels or “time slices.” The youngest of these is the archeological record (e.g., <10 k.y. B.P.), when organic matter from living organisms undergoes the preliminary stages of fossilization (certain classes of biomolecule are selectively preserved while others undergo rapid degradation). The second time slice is the Tertiary. Well-preserved fossils of this age retain diagenetically modified biomarkers and biopolymers for which a product-precursor relationship with the original biological materials can still be identified. The final time slice is the Carboniferous. Organic material of this age has generally undergone such extensive diagenetic degradation that only the most resistant biopolymers remain and these have undergone substantial modification. Trends through time in the taphonomy and utility of ancient biomolecules in terrigenous fossils affect their potential for studies that involve chemosystematic and environmental data.

scholarly journals EVALUATION OF THREE SURFACE FRICTION TECHNIQUES FOR THE REMOVAL OF ORGANIC MATTER

2015 ◽  
Vol 24 (4) ◽  
pp. 1061-1070 ◽  
Author(s):  
Marcelo Alessandro Rigotti ◽  
Adriano Menis Ferreira ◽  
Mara Corrêa Lelles Nogueira ◽  
Margarete Teresa Gottardo de Almeida ◽  
Odanir Garcia Guerra ◽  
...  
Keyword(s):  
Organic Matter ◽  
Adenosine Triphosphate ◽  
Organic Material ◽  
Surface Friction ◽  
Disinfection Process ◽  
Significant Difference ◽  
Before And After ◽  
Quantitative Descriptive ◽  
The One ◽  
Cleaning And Disinfection

ABSTRACT The objective of this study was to assess the effectiveness of three surface friction techniques for the removal of organic material. A quantitative, descriptive and exploratory study was developed to evaluate the presence or not of organic material before and after the cleaning and disinfection process of surfaces of bedside tables of patients hospitalized at an Intensive Care Unit. Three friction techniques were executed in the one-way, two-way and centrifugal sense, individually, three times on each table, during alternate weeks. For each patient unit and friction technique, a single table and three sides of cloth were used, moistened with 70% (w/v) alcohol. The organic matter was detected through the presence of adenosine triphosphate by bioluminescence, using 3M(tm) Clean-Trace(tm) ATP Systems. For each technique, 13 samples were collected before and 13 after the cleaning/disinfection process, totaling 78 samples of adenosine triphosphate by bioluminescence. No statistically significant difference was found among the removal techniques of organic matter. This study demonstrated that none of the three surface friction methods was better than the other to remove organic matter. Nevertheless, further research is needed in which other cleaning/disinfection indicators and surfaces are considered.

scholarly journals On the chemical dynamics of extracellular polysaccharides in the high Arctic surface microlayer

Ocean Science ◽  
2012 ◽  
Vol 8 (4) ◽  
pp. 401-418 ◽  
Author(s):  
Q. Gao ◽  
C. Leck ◽  
C. Rauschenberg ◽  
P. A. Matrai
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Compositional Analysis ◽  
Physicochemical Characteristics ◽  
High Arctic ◽  
The Arctic ◽  
Extracellular Polysaccharides ◽  
Surface Microlayer ◽  
Biological Origin ◽  
Ocean Study

Abstract. The surface microlayer (SML) represents a unique system of which the physicochemical characteristics may differ from those of the underlying subsurface seawater (SSW). Within the Arctic pack ice area, the SML has been characterized as enriched in small colloids of biological origin, resulting from extracellular polymeric secretions (EPS). During the Arctic Summer Cloud Ocean Study (ASCOS) in August 2008, particulate organic matter (POM, with size range > 0.22 μm) and dissolved organic matter (DOM, < 0.22 μm, obtained after filtration) samples were collected and chemically characterized from the SML and the corresponding SSW at an open lead centered at 87.5° N and 5° E. Total organic carbon was persistently enriched in the SML with a mean enrichment factor (EF) of 1.45 ± 0.41, whereas sporadic depletions of dissolved carbohydrates and amino acids were observed. Monosaccharide compositional analysis reveals that EPS in the Arctic lead was formed mainly of distinctive heteropolysaccharides, enriched in xylose, fucose and glucose. The mean concentrations of total hydrolysable neutral sugars in SSW were 94.9 ± 37.5 nM in high molecular weight (HMW) DOM (> 5 kDa) and 64.4 ± 14.5 nM in POM. The enrichment of polysaccharides in the SML appeared to be a common feature, with EFs ranging from 1.7 to 7.0 for particulate polysaccharides and 3.5 to 12.1 for polysaccharides in the HMW DOM fraction. A calculated monosaccharide yield suggests that polymers in the HMW DOM fraction were scavenged, without substantial degradation, into the SML. Bubble scavenging experiments showed that newly aggregated particles could be formed abiotically by coagulation of low molecular weight nanometer-sized gels. Aerosol particles, artificially generated by bubbling experiments, were enriched in polysaccharides by factors of 22–70, relative to the source seawater. We propose that bubble scavenging of surface-active polysaccharides could be one of the possible mechanisms for the enrichment of polysaccharides in the high Arctic open lead SML.

Evaluating the interaction of biofilms, organic matter and soil structures at the pore scale

2021 ◽  
Author(s):  
Alexander Prechtel ◽  
Simon Zech ◽  
Alice Lieu ◽  
Raphael Schulz ◽  
Nadja Ray
Keyword(s):  
Organic Matter ◽  
Structural Changes ◽  
Effective Diffusivity ◽  
Computational Domain ◽  
Pore Scale ◽  
Gas Phases ◽  
Soil Structures ◽  
Ldg Method ◽  
Conventional Models ◽  
Diffusive Processes

&lt;div class=&quot;description js-mathjax&quot;&gt; &lt;p&gt;Key functions of soils, such as permeability or habitat for microorganisms, are determined by structures at the microaggregate scale. The evolution of elemental distributions and dynamic processes can often not be assessed experimentally. So mechanistic models operating at the pore scale are needed.&lt;br /&gt;We consider the complex coupling of biological, chemical, and physical processes in a hybrid discrete-continuum modeling approach. It integrates dynamic wetting (liquid) and non-wetting (gas) phases including biofilms, diffusive processes for solutes, mobile bacteria transforming into immobile biomass, and ions which are prescribed by means of partial differential equations. Furthermore the growth of biofilms as, e.g., mucilage exuded by roots, or the distribution of particulate organic matter in the system, is incorporated in a cellular automaton framework (CAM) presented in [1, 2]. It also allows for structural changes of the porous medium itself (see, e.g. [3]). As the evolving computational domain leads to discrete discontinuities, we apply the local discontinuous Galerkin (LDG) method for the transport part. Mathematical upscaling techniques incorporate the information from the pore to the macroscale [1,4].&lt;br /&gt;The model is applied for two research questions: We model the incorporation and turnover of particulate OM influencing soil aggregation, including &amp;#8216;gluing&amp;#8217; hotspots, and show scenarios varying of OM input, turnover, or particle size distribution. &lt;br /&gt;Second, we quantify the effective diffusivity on 3D geometries from CT scans of a loamy and a sandy soil. Conventional models cannot account for natural pore geometries and varying phase properties. Upscaling allows also to quantify how root exudates (mucilage) can significantly alter the macroscopic soil hydraulic properties.&lt;/p&gt; &lt;/div&gt; &lt;div id=&quot;field-23&quot;&gt; &lt;p&gt;[1]&amp;#160; Ray, Rupp, Prechtel (2017). AWR (107), 393-404.&lt;br /&gt;[2] Rupp, Totsche, Prechtel, Ray (2018). Front. Env. Sci. (6) 96.&lt;br /&gt;[3] Zech, Dultz, Guggenberger, Prechtel, Ray (2020). Appl. Clay Sci. 198, 105845.&lt;br /&gt;[4] Ray, Rupp, Schulz, Knabner (2018). TPM 124(3), 803-824.&lt;/p&gt; &lt;/div&gt;

A Reassessment of the Routine Pretreatment Protocol for Radiocarbon Dating Cremated Bones

Radiocarbon ◽  
2016 ◽  
Vol 58 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Christophe Snoeck ◽  
Richard A Staff ◽  
Fiona Brock
Keyword(s):  
Organic Matter ◽  
Acetic Acid ◽  
Sodium Hypochlorite ◽  
Organic Material ◽  
Radiocarbon Dating ◽  
Sodium Chlorite ◽  
Radiocarbon Dates ◽  
Calcined Bone

AbstractIn the late 1990s, it was demonstrated that reliable radiocarbon dates could be obtained directly from cremated bone. Many 14C laboratories have since used a protocol for pretreating cremated (calcined) bones that consists of consecutive treatments with bleach and acetic acid to remove organic matter and extraneous or diagenetic carbonate, respectively. In most instances, the bleach used is sodium hypochlorite, although in recent years the Oxford Radiocarbon Accelerator Unit (ORAU) has used acidified sodium chlorite instead. However, properly calcined (white) bones should not contain any organic material; hence, the bleach treatment is potentially unnecessary. This article describes studies investigating the effectiveness of bleach (and the specific bleach used) during pretreatment of calcined bone, and demonstrates that 14C dates on six cremated bone samples are statistically indistinguishable whether or not the initial bleach step is applied.

THE GEOCHEMICAL CHARACTERIZATION OF AUSTRALIAN CRUDE OILS

1972 ◽  
Vol 12 (1) ◽  
pp. 125
Author(s):  
T.G. Powell ◽  
D.M. McKirdy
Keyword(s):  
Organic Matter ◽  
Organic Material ◽  
Depositional Environment ◽  
Land Plant ◽  
Crude Oils ◽  
Geochemical Characterization ◽  
Marine Organic Matter ◽  
Show Evidence ◽  
Lower Palaeozoic

Australian oils are generally light by world standards. They have API gravities greater than 35°, low sulphur and asphalt contents, and are of paraffinic or naphthenic base. The geochemical similarity of oils from the Bowen-Surat Basin, with the notable exception of the Conloi crude, is most marked in the fraction boiling above 250 °C. Oils from the Cooper, Gippsland and Otway Basins are probably derived from terrestrial organic material, but differ in their degree of maturation as indicated by n-alkane patterns. Samples from the Perth Basin exhibit a similar variation in maturity. In the Carnarvon Basin, the Windalia crude differs from those in deeper reservoirs in containing a higher proportion of oxygen-bearing, nitrogen-bearing, and sulphur-bearing compounds, another sign of a less mature oil. The East Mereenie oil displays an odd-even predominance in its n-alkane distribution which is characteristic of some Lower Palaeozoic crudes. A Papuan Basin condensate is the only available sample produced from a limestone reservoir. This probably accounts for its higher sulphur content. Two seeps obtained from the Papuan Highlands are inspissated residues which may have suffered microbiological alteration.A major control of the composition of Australian crude oils appears to be the depositional environment of the source rock. Most of the oils show evidence of having been generated, at least in part, from terrestrial (as opposed to marine) organic matter. The location of all but one of the reservoirs within sequences dominated by the sandstone - shale association is consistent with the likely contribution of land plant detritus to their source environment. Likewise, low sulphur and asphalt values reflect the scarcity of favourable carbonate-evaporite source and reservoir situations in Australia.

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

Pedosphere ◽  
2012 ◽  
Vol 22 (3) ◽  
pp. 283-293 ◽  
Author(s):  
C. NICOLÁS ◽  
G. MASCIANDARO ◽  
T. HERNÁNDEZ ◽  
C. GARCIA
Keyword(s):  
Organic Matter ◽  
Structural Changes ◽  
Organic Amendment ◽  
Arid Soil ◽  
Semi Arid
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