Title

Photochemistry and structure of environmental macromolecules

Date of Award

2003

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Oceanography

First Committee Member

Rod G. Zika, Committee Chair

Abstract

Presented is a novel combination of analytical techniques to make a direct determination of the molecular mass distribution of environmental macromolecules, focusing in particular on dissolved organic matter (DOM). Results from this new technique confirmed the presence of organic compounds in the 1000 to 2000 Da range that were indicated but not resolved using other methodologies. The application of a hydrophilic-lipophilic copolymer based extraction step reduced system bias due to variations in sample source, simplified extraction, and provided acceptable extraction efficiency. This combination of extraction and analysis allowed the determination of a correlation between absorbance and molecular mass distribution and abundance in river systems of southwestern Florida. A reduction in mean mass with environmental processing was observed. Investigation of an individual source of DOM, the degradation of the common seagrass Thalassia testudinum, revealed similar optical and mass spectral features as that observed in coastal DOM samples. A reduction in mean mass was observed during the photochemical processing of this material, which suggests that photochemistry may be responsible for the reduction in mean mass observed in coastal river samples. Implications for the calculation of mass distribution for DOM from satellite data and the need for future research into sources of DOM are discussed.

Keywords

Biology, Ecology; Biogeochemistry; Chemistry, Analytical; Environmental Sciences

Link to Full Text

http://access.library.miami.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3119915