HR: 1340h
AN: PP43B-1288    [Abstracts]
TI: Molecular Markers in the Quelccaya Ice Cap, Peru Describe 20th Century Biomass Burning Variability
AU: * Makou, M C
EM: makou.1@osu.edu
AF: Byrd Polar Research Center, The Ohio State University 1090 Carmack Road Scott Hall 108, Columbus, OH 43210, United States
AU: Thompson, L G
EM: thompson.3@osu.edu
AF: Byrd Polar Research Center, The Ohio State University 1090 Carmack Road Scott Hall 108, Columbus, OH 43210, United States
AU: Eglinton, T I
EM: teglinton@whoi.edu
AF: Woods Hole Oceanographic Institution, Dept. of Marine Chemistry and Geochemistry 360 Woods Hole Road, Woods Hole, MA 02543, United States
AU: Montluçon, D B
EM: dmontlucon@whoi.edu
AF: Woods Hole Oceanographic Institution, Dept. of Marine Chemistry and Geochemistry 360 Woods Hole Road, Woods Hole, MA 02543, United States
AB: Organic geochemical analytical methods were applied to Andean ice core samples, resulting in a multi- molecular biomass burning record spanning 1915 to 2001 AD. The Quelccaya Ice Cap in Peru is situated on the eastern flank of the Andes at 14°S and is well situated to receive aeolian inputs of organic matter derived from Amazonian forest fire events. Compounds of interest, which occur in trace quantities in ice, were recovered by stir bar sorptive extraction and analyzed by gas chromatography/time-of-flight mass spectrometry coupled with thermal desorption. These methods permitted identification and quantitation of numerous biomarkers in sample volumes of as little as 10 ml. At least one wet and dry season sample was analyzed for every year. Observed biomarkers that may be derived from vegetation fires include several polycyclic aromatic hydrocarbons (PAHs), atraric acid, 2-ethylhexyl p-methoxycinnamate, and a range of other aromatic compounds. Abrupt changes in compound abundances were superimposed on decadal variability. Systematic offsets between wet and dry season abundances were not observed, suggesting that the biomass burning signal is not biased by seasonal depositional effects, such as dust delivery. Inputs likely reflect a combination of sources from anthropogenic burning of the Amazon rainforest as well as natural fires related to aridity, and include both high and low elevation vegetation. These compounds and techniques can be applied to older ice in this and other core locations as an independent estimate of aridity.
DE: 0724 Ice cores (4932)
DE: 1055 Organic and biogenic geochemistry
DE: 4902 Anthropogenic effects (1803, 4802)
DE: 4904 Atmospheric transport and circulation
DE: 4924 Geochemical tracers
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting