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One of the defining characteristics of a biomarker is the retention, during diagenesis, of structural characteristics indicative of its original biogenic source (Peters and Moldowan, 1993). Since the 1960s an increasing interest has developed in the use of environmental biomarker compounds to monitor levels of human and animal waste introduced to marine and(More)
In an effort to understand the relationships between both the lipid content and δ13C values of Collembola and their diet, isotopically labelled (C3 and C4) bakers’ yeasts were cultured and fed to two Collembolan species, Folsomia candida and Proisotoma minuta. The fatty acid composition of Collembola generally reflected that of the diet with the addition of(More)
Well-drained non-agricultural soils mediate the oxidation of methane directly from the atmosphere, contributing 5 to 10% towards the global methane sink. Studies of methane oxidation kinetics in soil infer the activity of two methanotrophic populations: one that is only active at high methane concentrations (low affinity) and another that tolerates(More)
Lipid extracts from four long-term experiments (Broadbalk Wilderness, Geescroft Wilderness, Hoos®eld Spring Barley and Park Grass) were analysed using a combination of gas chromatography, gas chromatography±mass spectrometry and gas chromatography±combustion±isotope ratio mass spectrometry. The lipid content of the primary organic inputs for each soil were(More)
The introduction of (13)C-labelled substrates to soils, sediments or cultures followed by (13)C analysis of phospholipid fatty acids (PLFAs) provides quantitative and chemotaxonomic information for the groups of microorganisms utilizing a given substrate. Gas chromatography-combustion-isotope ratio mass spectrometry has provided the high precision necessary(More)
Today, insular Southeast Asia is important for both its remarkably rich biodiversity and globally significant roles in atmospheric and oceanic circulation. Despite the fundamental importance of environmental history for diversity and conservation, there is little primary evidence concerning the nature of vegetation in north equatorial Southeast Asia during(More)
The objective of this study was to assess archaeol, a membrane lipid present in methanogenic Archaea, in cattle feces as a molecular proxy for methanogenesis in the rumen. Feces from 16 heifers either in early lactation [71 d in milk (DIM)] or mid lactation (120 DIM), consuming a diet consisting of 30/70 grass silage/concentrates [dry matter (DM) basis],(More)
Total lipid extracts (TLEs) of grass (aerial and sub-aerial, Holcus lanatus ) from a plot on a long-term grassland experiment, and associated soil, along with the organic fraction of the TLE hydrolysates and the hydrolysates of the solvent extracted vegetation have been separated into fractions containing speci®c compound classes and analysed using gas(More)
Fatty acid ethyl esters are secondary metabolites that are produced during microbial fermentation, in fruiting plants and in higher organisms during ethanol stress. In particular, volatile medium-chain fatty acid ethyl esters are important flavour compounds that impart desirable fruit aromas to fermented beverages, including beer and wine. The biochemical(More)
The targeting of mcrA or 16S rRNA genes by quantitative PCR (qPCR) has become the dominant method for quantifying methanogens in rumen. There are considerable discrepancies between estimates based on different primer sets, and the literature is equivocal about the relationship with methane production. There are a number of problems with qPCR, including low(More)