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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Polar organic compounds as tracers of environmental processes

Medeiros, Patricia Matheus de 01 June 2006 (has links)
Sources of polar/water-soluble organic compounds conjunctly with apolar biomarkers were characterized in natural organic matter. This multi-biomarker approach was accomplished by a simple analytical method consisting of extraction with dichloromethane:methanol (2:1, v/v), silylation and analysis by gaschromatography- mass spectrometry (GC-MS). Polar and apolar biomarkers, derived mainly from higher plants and microorganisms, were used as tracers of processes occurring in the environmental compartments and registered in aerosol, soil and sediment samples. Sugars (monosaccharides, disaccharides, anhydrosugars and sugar alcohols) were utilized to trace seasonal variation inputs of biogenic organic carbon to aerosols over a pristine forest and the passage of a smoke plume from the long-range transport wildfire emissions. Sugars and fatty acid methyl esters were target compounds used to better understand the plant-microorganism dynamics in a ryegrass soil over a one-year period. Distributions and abundances of straight chain homologous series (n-alkanes, n-alkanols, n-alkanoic acids), cyclic components (e.g., diterpenoids, triterpenoids, steroids) and polar biomakers (e.g., sugars) were determined for sediment and smoke samples. In the first study, the transport and alterations of major terrestrial biomarkers were assessed for small rivers draining the northwestern US. In the latter, biomarkers and their thermal alteration derivatives were identified in smoke emissions from known temperate and semi-arid green vegetation to be applied as tracers of wildfires. This work demonstrated that a multi-biomarker tracer analysis is a useful tool for describing and understanding the biogeochemistry occurring in various environmental compartments. / Graduation date: 2006

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