HR: 0800h
AN: B51C-0612    [Abstracts]
TI: Novel Penta-Unsaturated Alkenones From Lake Fryxell, Antarctica
AU: * Jaraula, C B
EM: cjarau1@uic.edu
AF: Department of Earth and Environmental Sciences, University of Illinois at Chicago, 845 W Taylor St., Chicago, IL 60607-7059, United States
AU: Brassell, S C
EM: simon@indiana.edu
AF: Department of Geological Sciences, Indiana University, 1001 East 10th St., Bloomington, IN 47405-1405, United States
AU: Kenig, F
EM: fkenig@uic.edu
AF: Department of Earth and Environmental Sciences, University of Illinois at Chicago, 845 W Taylor St., Chicago, IL 60607-7059, United States
AU: Doran, P T
EM: pdoran@uic.edu
AF: Department of Earth and Environmental Sciences, University of Illinois at Chicago, 845 W Taylor St., Chicago, IL 60607-7059, United States
AB: Novel methyl octatriaconta-pentaen-one (C_38:5m), methyl and ethyl nonatriaconta-pentaen-one (C_39:5m and C_39:5e, respectively) and methyl tetradec-pentaen-one (C_40:5m) are identified from chromatographic and mass spectrometric properties of a bottom sediment sample from perennially ice-covered Lake Fryxell in Antarctica. The pentaunsaturated alkenones comprise 15%, 28% and 12% of the total C₃₈, C₃₉ and C₄₀ homologous series. These alkenone biomarkers also consist of tetra , tri-, and diunsaturated methyl and ethyl ketones from C₃₇ to C₄₀. Low salinity and extremely cold conditions year round may have strongly influenced the number of unsaturations in the biomarkers and chain length of the alkenones. As also suggested by accompanying cholesterol and alkene biomarkers, these alkenones are key biomarkers of haptophycean algae of the Class Prymnesiophyceae, but the specific species that biosynthesizes these alkenones in the lake are still unknown.
DE: 0456 Life in extreme environments
DE: 0458 Limnology (1845, 4239, 4942)
DE: 0473 Paleoclimatology and paleoceanography (3344, 4900)
DE: 1055 Organic and biogenic geochemistry
DE: 4954 Sea surface temperature
SC: Biogeosciences [B]
MN: 2007 Fall Meeting