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Showing 1 to 9 of 9 for “"Alkenones"”.
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Determination of sediment provenance at drift sites using hydrogen isotopes in lipids
… We hypothesize that hydrogen isotope ratios of alkenones, a class of lipids from phytoplankton, may provide insight into the source of fine fraction sediment. Because of their restricted sources, broad geographic distribution, and excellent preservation properties, alkenones are of particular …
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Determination of sediment provenance at drift sites using hydrogen isotopes in lipids
… We hypothesize that hydrogen isotope ratios of alkenones, a class of lipids from phytoplankton, may provide insight into the source of fine fraction sediment. Because of their restricted sources, broad geographic distribution, and excellent preservation properties, alkenones are of particular …
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Refinement and application of a new paleotemperature estimation technique
… the unsaturation ratio of long chain C37 methyl alkenones (Uk37) produced by Prymnesiophyceae phytoplankton, has been applied to late Quaternary sediment cores. Previous studies have shown that the Uk37 ratio of these alkenones is linearly proportional to the sea-water temperature in which the …
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An organic geochemical approach to problems of glacial-interglacial climatic variability
… of total long chain (C37-C39) unsaturated alkenones and individual C27-C29 desmethyl sterols were determined to be useful proportional indicators of preserved marine and terrigenous organic carbon, respectively. The a1kenones, whose source is marine phytoplankton of the class …
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Palaeoenvironmental reconstruction of late Holocene climate dynamics in Southwest Africa using a multi-proxy characterization of Namaqualand mudbelt sediments
… an additional record of SST, independent of alkenones, which elicited a com- parative study between SST TEX86 and SST UK'37 . The comparison facilitated a review of the effectiveness of TEX 86 within the Benguela Upwelling System, and assisted in quantifying reasons for the observed …
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Sedimentary lipids as indicators of depositional conditions in the coastal Peruvian upwelling regime
… A variety of lipids (n-alkanes, n-alkanols, C37 alkenones, hopanoids, keto-ols, lycopane, phytol, stenols, stanols, sterenes, and tetrahymanol) were quantified in Peru margin sediments from both the oxygen minimum zone (OMZ) and several near-shore locations. I discuss the utility of the lipid …
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Glacial-Interglacial Variability of Eastern Pacific Hydroclimate
Unprecedented drought conditions in southwest North America (SWNA, defined as the region from southern California to southern Mexico, west of the continental divide) has raised alarms regarding water resource scarcity in a region with dense urban populations and vital agricultural industries. …
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Palaeoceanographic conditions and palaeoproductivity changes from the sub-Antarctic island South Georgia since the late deglacial, using marine micropalaeontology and geochemistry
This thesis presents a high-resolution multiproxy reconstruction of palaeoceanographic conditions and palaeoproductivity on the South Georgia shelf spanning the late deglacial through the Holocene. South Georgia lies within the path of the Antarctic Circumpolar Current (ACC) and the Southern …
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Investigations on rainfall variability during the late Quaternary based on geochemical analyses of lake sediments from tropical and subtropical southern Africa
This thesis presents investigations on sediments from two African lakes which have been recording changes in their surrounding environmental and climate conditions since more than 200,000 years. Focus of this work is the time of the last Glacial and the Holocene (the last ~100,000 years before …