HR: 16:00h
AN: PP14B-01    [Abstracts]
TI: Investigation of Molecular Marker Lipids in Alpine Ice Cores Via Stir Bar Sorptive Extraction
AU: * Makou, M C
EM: mmakou@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 United States
AU: Eglinton, T I
PP14B-01 AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 United States
AU: Thompson, L G
PP14B-01 AF: Byrd Polar Research Center, Ohio State University, 108 Scott Hall 1090 Carmack Road, Columbus, OH 43210 United States
AU: Hughen, K A
PP14B-01 AF: Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543 United States
AB: Recently developed analytical techniques were employed to identify and quantify organic molecular markers trapped in high-altitude ice. While various compounds represent potentially useful proxies for biomass burning, vegetation type, atmospheric circulation, and anthropogenic activity, prior attempts to measure organic compounds in ice cores have typically required large volumes of sample material that are incompatible with generation of high-resolution paleoclimate records. We employed stir bar sorptive extraction (SBSE) and thermal desorption (TD), coupled with gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS), to examine the organic content of small quantities (≤ 30 ml) of ice. To test the utility of the approach, post-industrial ice core samples from the Huascarán and Sajama sites (Andes), the Dasuopu and Puruogangri sites (Tibetan Plateau), and Mt. Kilimanjaro (east Africa) were tested. n-Alkanes, n-alkanoic acids, n-alkyl amides and nitriles, polycyclic aromatic hydrocarbons (PAHs), and various diterpenoids were identified in this suite of cores. These marker compounds suggest inputs from biomass burning, fresh vascular plant material, and anthropogenic activities such as fossil fuel combustion. Differences in distributions of the alkyl amide and nitrile homologues between the different sites suggest a predominantly local or regional supply of organic matter. Pre-industrial samples from the Sajama and Puruogangri ice cores were also analyzed in order to assess the character of biomarker assemblages in the absence of anthropogenic contributions and investigate changes in inputs over time. PAHs and diterpenoids, which may result from biomass burning and were observed in the modern Sajama samples, occurred in two Holocene Sajama samples, but not in a last glacial sample. Enhanced inputs of terrestrial vegetation combustion biomarkers were consistent with periods of enhanced aridity in both cores. This study demonstrates the utility of SBSE, TD, and GC/TOF-MS for isolating organic compounds from small amounts of alpine ice and paves the way for development of high-resolution molecular stratigraphic records from tropical ice cores.
DE: 4904 Atmospheric transport and circulation
DE: 4914 Continental climate records
DE: 4932 Ice cores (0724)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005