Search Results - "Volkman, John K."

Acyclic isoprenoid biomarkers and evolution of biosynthetic pathways in green microalgae of the genus Botryococcus by Volkman, John K.

“…•The botryococcene and lycopadiene biosynthetic pathways appear to be no older than the Eocene.•Algae presently recognised as Botryococcus braunii are likely…”
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Sterols and other triterpenoids: source specificity and evolution of biosynthetic pathways by Volkman, John K.

“…The source specificity and biosynthesis of cyclic isoprenoids such as hopanoids, sterols and pentacyclic triterpenoids, which are commonly used as biomarkers…”
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Biomarker evidence for Botryococcus and a methane cycle in the Eocene Huadian oil shale, NE China by Volkman, John K., Zhang, Zhirong, Xie, Xiaomin, Qin, Jianzhong, Borjigin, Tenger

“…•The organic-rich Eocene Huadian oil shale contains abundant microalgal lipids.•Isotopically depleted δ13C values for hop-17(21)-enes and neohopenes indicated…”
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Archaeal ammonia oxidizers and nirS-type denitrifiers dominate sediment nitrifying and denitrifying populations in a subtropical macrotidal estuary by Abell, Guy C J, Revill, Andrew T, Smith, Craig, Bissett, Andrew P, Volkman, John K, Robert, Stanley S

“…Nitrification and denitrification are key steps in nitrogen (N) cycling. The coupling of these processes, which affects the flow of N in ecosystems, requires…”
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Degradation of sterols and terrigenous organic matter in waters of the Mackenzie Shelf, Canadian Arctic by Rontani, Jean-François, Charrière, Bruno, Sempéré, Richard, Doxaran, David, Vaultier, Frédéric, Vonk, Jorien E., Volkman, John K.

“…•Strong biotic and abiotic degradation of TOM on the Beaufort Shelf observed.•Autoxidation state of TOM appeared to correlate with salinity.•Contact of TOM…”
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Organic matter sources in an enclosed coastal inlet assessed using lipid biomarkers and stable isotopes by Volkman, John K., Revill, Andrew T., Holdsworth, Daniel G., Fredericks, David

“…The sources of organic matter (OM) in surface sediments from Wilson Inlet, an enclosed and seasonally barred inlet in Western Australia, have been determined…”
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Structural characterization and mass spectrometry fragmentation signatures of macrocyclic alkanes isolated from a Sydney Basin torbanite, Australia by Meng, Xianxin, Lu, Hong, Zhang, Zhirong, Peng, Ping’an, Volkman, John K.

“…Individual hydrocarbons identified to be macrocyclic alkanes in a torbanite from the Sydney Basin (Australia) were successfully isolated from its extracts…”
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High-throughput analysis of ammonia oxidiser community composition via a novel, amoA-based functional gene array by Abell, Guy C J, Robert, Stan S, Frampton, Dion M F, Volkman, John K, Rizwi, Farhan, Csontos, József, Bodrossy, Levente

“…Advances in microbial ecology research are more often than not limited by the capabilities of available methodologies. Aerobic autotrophic nitrification is one…”
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Sources for sedimentary bacteriohopanepolyols as revealed by 16S rDNA stratigraphy by Coolen, Marco J.L, Talbot, Helen M, Abbas, Ben A, Ward, Christopher, Schouten, Stefan, Volkman, John K, Damsté, Jaap S. Sinninghe

“…Bacteriohopanoids are widespread lipid biomarkers in the sedimentary record. Many aerobic and anaerobic bacteria are potential sources of these lipids which…”
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Phytol degradation products as biogeochemical tracers in aquatic environments by Rontani, Jean-François, Volkman, John K.

“…Phytol (the ester-linked side-chain of chlorophyll- a) is perhaps the most studied biomarker of those found in modern aquatic environments. This paper reviews…”
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Evolution of the methane cycle in Ace Lake (Antarctica) during the Holocene: response of methanogens and methanotrophs to environmental change by Coolen, Marco J.L., Hopmans, Ellen C., Rijpstra, W. Irene C., Muyzer, Gerard, Schouten, Stefan, Volkman, John K., Sinninghe Damsté, Jaap S.

“…Post-glacial Ace Lake (Vestfold Hills, Antarctica), which was initially a freshwater lake and then an open marine system, is currently a meromictic basin with…”
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Microalgal biomarkers: A review of recent research developments by Volkman, John K, Barrett, Stephanie M, Blackburn, Susan I, Mansour, Maged P, Sikes, Elisabeth L, Gelin, François

“…Microalgae are major sources of lipids in lacustrine and marine environments. This paper provides a review of some recent advances in our knowledge of the wide…”
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Lipid characterization of coastal hypersaline cyanobacterial mats from the Camargue (France) by Rontani, Jean-François, Volkman, John K.

“…A study of the sedimentary lipids of coastal hypersaline microbial mats sampled in the Camargue (France) allowed identification of the predominant inputs of…”
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Sources of organic matter in sediments from the Ord River in tropical northern Australia by Volkman, John K., Revill, Andrew T., Bonham, Pru I., Clementson, Lesley A.

“…The sources of organic matter in the sediments from the Ord River and estuary were assessed using stable carbon isotope values (δ 13C), lipid biomarkers and…”
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The effect of growth phase on the lipid class, fatty acid and sterol composition in the marine dinoflagellate, Gymnodinium sp. in batch culture by Mansour, Maged P, Volkman, John K, Blackburn, Susan I

“…We have studied the effects of growth phase on the lipid composition in batch cultures of Gymnodinium sp. CS-380/3 over 43 days of culturing. The lipid content…”
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Cryptophyceae and rhodophyceae; chemotaxonomy, phylogeny, and application by Dunstan, Graeme. A., Brown, Malcolm R., Volkman, John. K.

“…It is postulated that the primary endosymbiosis of a photosynthetic n − 3 C 18 PUFA-producing prokaryotic cyanobacteria and a eukaryotic host capable of chain…”
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Long-chain alkenones and related compounds in the benthic haptophyte Chrysotila lamellosa Anand HAP 17 by Rontani, J.F, Beker, B, Volkman, J.K

“…The neutral lipid compositions of the coastal haptophyte Chrysotila lamellosa HAP 17 grown in batch culture at 10 and 20 degrees C have been determined. A…”
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Widespread Sterol Methyltransferase Participates in the Biosynthesis of Both C4α- and C4β-Methyl Sterols by Zhou, Wenxu, Zhang, Xu, Wang, Aoqi, Yang, Lin, Gan, Qinhua, Yi, Liang, Summons, Roger E., Volkman, John K., Lu, Yandu

“…The 4-methyl steranes serve as molecular fossils and are used for studying both eukaryotic evolution and geological history. The occurrence of 4α-methyl…”
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Geochemical characterization and artificial thermal maturation of kerogen density fractions from the Eocene Huadian oil shale, NE China by Xie, Xiaomin, Li, Maowen, Xu, Jin, Snowdon, Lloyd R., Volkman, John K.

“…•Quantitative oil shale maceral concentrates were obtained from an Eocene Huadian oil shale.•Density separated maceral groups had different petroleum…”
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Occurrence of gorgosterol in diatoms of the genus Delphineis by Rampen, Sebastiaan W., Volkman, John K., Hur, Sung Bum, Abbas, Ben A., Schouten, Stefan, Jameson, Ian D., Holdsworth, Daniel G., Bae, Jean Hee, Sinninghe Damsté, Jaap S.

“…The presence of the C30 sterol gorgosterol (22,23-methylene-23,24-dimethylcholest-5-en-3ß-ol) and its analogues in some marine and freshwater environments is…”
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