HR: 0830h
AN: B31E-0355    [PDF]
TI: Analysis of Southern African Aerosols Using Bulk Stable Isotope Analysis
AU: Macko, S A
EM: sam8f@virginia.edu
AF: University of Virginia, Department of Environmental Sciences Clark Hall Box 400123, Charlottesville, VA 22904-4123 United States
AU: * Billmark, K A
EM: kbillmark@virginia.edu
AF: University of Virginia, Department of Environmental Sciences Clark Hall Box 400123, Charlottesville, VA 22904-4123 United States
AU: Swap, R J
EM: swapper@virginia.edu
AF: University of Virginia, Department of Environmental Sciences Clark Hall Box 400123, Charlottesville, VA 22904-4123 United States
AB: In southern Africa, emissions from industrial fossil fuel combustion, extensive biomass burning, as well as eolian dust and marine aerosols affect biogeochemical processes. Chemical characterization of aerosols is crucial to understanding their role in nutrient cycling. This study analyzed the organic carbon, nitrogen and sulfur bulk stable isotope compositions of total suspended particulate aerosols as a function of geographical and diurnal differences for sites throughout southern Africa. A regional approach showed isotopic differences in the aerosols collected in different seasons, where primarily C$_{3}$ vegetation influenced dry season aerosol compositions and C$_{4}$ vegetation influenced wet season aerosol samples. Dry season samples showed a significant enrichment of $\delta$$^{13}$C and $\delta$$^{15}$N with increasing mean annual precipitation (MAP). Wet season samples showed a significant depletion in $^{15}$N with increasing MAP. These results were related to the relative contributions of C$_{3}$ and C$_{4}$ vegetation to aerosols at each site and to changes in the isotopic signature of nitrogen source pools. These results further suggest that location specific processes drive aerosol production in the wet season, whereas regional processes contribute more importantly in the dry season.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0345 Pollution--urban and regional (0305)
DE: 1040 Isotopic composition/chemistry
DE: 1615 Biogeochemical processes (4805)
DE: 9305 Africa
SC: Biogeosciences [B]
MN: 2003 Fall Meeting