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Showing 1 to 9 of 9 for “"Highly-Branched Isoprenoid"”.
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SOURCES AND STRUCTURES OF COMMONLY OCCURRING HIGHLY BRANCHED ISOPRENOID ALKENES
Highly branched isoprenoid (HBI) alkenes are ubiquitous lipids which have been identified in numerous geochemical samples, ranging from recent sediments to ancient oils. At the outset of the current investigation, the diatomaceous algae Haslea ostrearia (C25 alkenes) and Rhizosolenia setigera (C25 …
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STRUCTURAL CHARACTERISATION OF HIGHLY BRANCHED ISOPRENOID ALKENES FROM SEDIMENTS AND ALGAE
At least fourteen C25 highly branched isoprenoid (HBI) alkenes have been previously reported in estuarine and coastal sediments from locations worldwide. The parent alkane structure has been proven but only a few of the double bond positions established previously. A wide body of evidence suggests …
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Structural Characterisation and the Diagenetic Pathways of C25 Highly Branched Isoprenoid Hydrocarbons
Highly branched isoprenoid (HBI) hydrocarbons have been widely reported in recent sediments. It is known that two species of diatomaceous algae, the diatoms Haslea ostrearia and Rhizosolenia setigera are able to biosynthesise C25 HBI alkenes. Large scale cultures of H. ostrearia studied previously, …
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Reconstruction of recent and palaeo sea ice conditions in the Barents Sea
IP25 is a highly branched isoprenoid alkene derived from certain Arctic sea ice diatoms that, when detected in marine sediments, has been used as a proxy for past Arctic sea ice over the last decade. In the current study, the structure of this biomarker was determined following large-scale …
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Development of biomarker-based proxy methods for reconstructing the late Quaternary sea ice history in the Barents Sea
Application of the sympagic diatom-produced, C25 highly branched isoprenoid (HBI) termed IP25 to paleo-sea ice reconstruction has confirmed its utility as a qualitative seasonal sea ice proxy. Combination of IP25 and a pelagic biomarker into the Phytoplankton-IP25 index (PIP25) has facilitated more …
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ORIGINS AND SHORT-TERM SEDIMENTARY FATE OF GLOBALLY DISTRIBUTED BIOLOGICAL MARKER HYDROCARBONS
Nearly thirty C20, C25, and C30 highly branched isoprenoid (HBI) hydrocarbons have been detected, sometimes in high concentrations, in recent freshwater, estuarine, coastal and hypersaline sediments, and water column particulate matter from numerous locations worldwide. The parent structures have …
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Development of biomarker-based proxies for paleo sea-ice reconstructions
… diatom biomarker IP25 (a mono-unsaturated Highly Branched Isoprenoid (HBI) alkene) in Arctic marine sediments has previously been shown to provide a useful qualitative proxy measure for the past spring sea-ice occurrence. In the Southern Ocean the occurrence and variable abundance of a …
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Unravelling the impacts of palaeoecology, palaeoenvironment and lithofacies on sedimentary organic NSO compounds
… as signatures of protein-rich marine algae. The highly aliphatic algaenan of Botryococcus braunii sterically protects its oxygen-bearing groups leading to a great abundance of Ox compounds, furthermore, it characterizes the Botryococcus braunii source by substantial heteroatomic compounds …
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Aquatic macrophyte-derived biomarkers as palaeolimnological proxies on the Tibetan Plateau
… abundance in many Tibetan lakes. They can show highly 13C-enriched biomass because of their carbon metabolism and it is therefore crucial for the interpretation of δ13C values in sediment cores to understand to which extent aquatic macrophytes contribute to the isotopic signal of the sediments …