Student Research Day Abstracts and Posters

Document Type

Poster

Publication Date

Spring 5-14-2015

Faculty Advisor(s)

Warren de Bruyn

Abstract

Oxygenated hydrocarbons are ubiquitous in the atmosphere with levels ranging from low ppt (acetaldehyde) to low ppb(methanol). As an OH sink and an atmospheric HOx source, oxygenated hydrocarbons have a direct impact on the oxidative capacity of the atmosphere. A better understanding of the processes that produce and destroy these species in natural water would improve our understanding of the role that these systems play in cycling these species into or out of the atmosphere. These species can be lost to chemical, photochemical, and partical mediated (abiotic and biotic) processes in natural waters. Chemical loss and photochemical loss are believed to be negligible. Chemical and particle mediated degradation rates of acetaldehyde were measured in a southern california coastal wetland over a 6 month period. Corrolation between partical mediated rates and bacteria levels suggest that loss is primarily due to bacterial consumption. All samples were collected in the coastal waters of Newport Back bay, the inland delta in Newport Beach, California. Degradation rates were determined by measuring concentrations of D-4 labeled acetaldehyde in seawater samples spiked to nM levels in 100-mL glass syringes over time. Isotope dilution purge and trap gas chromatography mass spectrometry using C-13 labeled acetaldehyde as an internal standard was used to determine concentrations. Degradation rates were not measurable for 0.2-µm filtered seawater samples.

Comments

Presented at the Spring 2015 Student Research Day at Chapman University.

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