scholarly journals Preservation of uropygial gland lipids in a 48-million-year-old bird

2017 ◽  
Vol 284 (1865) ◽  
pp. 20171050 ◽  
Author(s):  
Shane O'Reilly ◽  
Roger Summons ◽  
Gerald Mayr ◽  
Jakob Vinther
Keyword(s):  
Potential Role ◽  
Organic Molecules ◽  
Wax Ester ◽  
Uropygial Gland ◽  
Pyrolysis Gas ◽  
Exceptional Preservation ◽  
Modern Bird ◽  
Gas Chromatography Mass Spectroscopy ◽  
Chain Lengths ◽  
Host Sediment

Although various kinds of organic molecules are known to occur in fossils and rocks, most soft tissue preservation in animals is attributed to melanin or porphyrins. Lipids are particularly stable over time—as diagenetically altered ‘geolipids’ or as major molecular constituents of kerogen or fossil ‘geopolymers’—and may be expected to be preserved in certain vertebrate tissues. Here we analysed lipid residues from the uropygial gland of an early Eocene bird using pyrolysis gas chromatography mass spectroscopy. We found a pattern of aliphatic molecules in the fossil gland that was distinct from the host oil shale sediment matrix and from feathers of the same fossil. The fossil gland contained abundant n -alkenes, n -alkanes and alkylbenzenes with chain lengths greater than 20, as well as functionalized long-chain aldehydes, ketones, alkylnitriles and alkylthiophenes that were not detected in host sediment or fossil feathers. By comparison with modern bird uropygial gland wax esters, we show that these molecular fossils are likely derived from endogenous wax ester fatty alcohols and fatty acids that survived initial decay and underwent early diagenetic geopolymerization. These data demonstrate the high fidelity preservation of the uropygial gland waxes and showcase the resilience of lipids over geologic time and their potential role in the exceptional preservation of lipid-rich tissues of macrofossils.

Fire effects on soil organic matter content, composition, and nutrients in boreal interior Alaska

2005 ◽  
Vol 35 (9) ◽  
pp. 2178-2187 ◽  
Author(s):  
J C Neff ◽  
J W Harden ◽  
G Gleixner
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Matter Content ◽  
Fire Effects ◽  
Matter Content ◽  
Soil Horizon ◽  
Surface Soils ◽  
Pyrolysis Gas ◽  
Gas Chromatography Mass Spectroscopy ◽  
Potassium Magnesium

Boreal ecosystems contain a substantial fraction of the earth's soil carbon stores and are prone to frequent and severe wildfires. In this study, we examine changes in element and organic matter stocks due to a 1999 wildfire in Alaska. One year after the wildfire, burned soils contained between 1071 and 1420 g/m2 less carbon than unburned soils. Burned soils had lower nitrogen than unburned soils, higher calcium, and nearly unchanged potassium, magnesium, and phosphorus stocks. Burned surface soils tended to have higher concentrations of noncombustible elements such as calcium, potassium, magnesium, and phosphorus compared with unburned soils. Combustion losses of carbon were mostly limited to surface dead moss and fibric horizons, with no change in the underlying mineral horizons. Burning caused significant changes in soil organic matter structure, with a 12% higher ratio of carbon to combustible organic matter in surface burned horizons compared with unburned horizons. Pyrolysis gas chromatography – mass spectroscopy also shows preferential volatilization of polysaccharide-derived organic matter and enrichment of lignin- and lipid-derived compounds in surface soils. The chemistry of deeper soil layers in burned and unburned sites was similar, suggesting that immediate fire impacts were restricted to the surface soil horizon.

scholarly journals Better molecular preservation of organic matter in an oxic than in a sulphidic depositional environment: evidence from of <i>Thalassiphora pelagica</i> (Dinoflagellata, Eocene) cysts

2019 ◽  
Author(s):  
Gerard J. M. Versteegh ◽  
Alexander J. P. Houben ◽  
Karin A. F. Zonneveld
Keyword(s):  
Organic Matter ◽  
Depositional Environment ◽  
Kerguelen Plateau ◽  
Reactive Component ◽  
Pyrolysis Gas ◽  
Rhine Graben ◽  
Specific Morphology ◽  
Initial Hypothesis ◽  
Gas Chromatography Mass Spectroscopy ◽  
Species Specific

Abstract. Anoxic sediments as compared to oxic settings encompass a much higher proportion of relatively labile and thus more reactive organic matter, naturally giving rise to condensation reactions (such as vulcanisation) transforming the original biomolecules into geomolecules. For the oxic environment where the labile, reactive, component is rapidly removed, such transformation and condensation is much less likely so that one would expect a structurally much better preservation of the more refractory initial biomolecules. To test this hypothesis, initially identical biomolecules need to be compared between different preservational environments. Here, we use the species specific morphology of organic microfossils to assure a single initial biosynthetic product (the cysts of the fossil dinoflagellate species Thallasiphora pelagica) for comparison. We assess the macromolecular structures of cysts from the Eocene (~ 40 Ma) sulphidic Rhine Graben and the oxic Kerguelen Plateau and compare them with each other and the structures of recent cysts. While between the sites the T. pelagica cysts are morphologically identical, pyrolysis gas chromatography mass spectroscopy and micro Fourier transform infra red analyses show that their macromolecular characteristics are strongly different. The cysts deposited in the sulphidic Rhine Graben show a strong contribution of long-chain aliphatic moieties and organic sulphur, absent in the material deposited on the oxic Kerguelen Plateau. Comparison with recent cyst walls suggests a much better molecular preservation for the oxic depositional environment, confirming our initial hypothesis. This leads to the conclusion that the best preservation of molecular structure is not necessarily where most organic matter gets preserved, which, in turn, is important for understanding the nature and fate of sedimentary organic matter.

Analysis of the Antisapstain Chemical Didecyldimethylammonium Chloride (DDAC) on Wood Surfaces by Diffuse Reflectance Fourier Transform Infrared Spectroscopy

1997 ◽  
Vol 51 (5) ◽  
pp. 721-724 ◽  
Author(s):  
J. F. Manville ◽  
J. R. Nault
Keyword(s):  
Promising Technique ◽  
Pyrolysis Gas ◽  
Partial Least Squares Analysis ◽  
Industrial Setting ◽  
Didecyldimethylammonium Chloride ◽  
Ft Ir ◽  
Quantitative Analyses ◽  
Gas Chromatography Mass Spectroscopy ◽  
Wood Surfaces ◽  
Selection Of

Reflectance FT-IR has been shown to be a promising technique for rapid (≤2 seconds) quantitative determinations of the antisapstain chemical didecyldimethylammonium chloride (DDAC) on wood surfaces treated at 0 to 88 μg/cm2. Partial least-squares analysis allowed selection of a region of the infrared spectra which could be used for quantitative analyses of DDAC on the wood. The results obtained through this method were comparable to results obtained on the same samples by HPLC and pyrolysis–gas chromatography/mass spectroscopy. This outcome demonstrates the opportunity for applying this FT-IR technique in an industrial setting.

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