Date of Award
Master of Science in Oceanography
Fluorophoric dissolved organic matter (FDOM) is an important component of the carbon cycle, factors in nutrient cycling, plays a role in determining the fates of trace metals and hydrophobic organic contaminants, and influences the inherent optical properties of water, affecting photosynthetic activities, productivity, and abundance of organisms in the area.
Fluorescence spectroscopy is a sensitive analytical method that can be used in conjunction with the canonical decomposition parallel factor analysis (PARAFAC) to separate component fluorescence signatures embedded in excitation-emission matrices (EEMs) of complex chemical mixtures. In this study, the methods of fluorescence spectroscopy and PARAFAC were used to determine the components of FDOM in Narragansett Bay. The PARAFAC model is input a 3-D array consisting of EEMs of unconcentrated samples from various locations in Narragansett Bay. The model deconvolves these natural mixture EEMs into individual EEM components and assigns relative concentrations for each component. Original component fluorescence signatures are not needed by the model but they improve the accuracy of the deconvolution. At least five FDOM components exist in Narragansett Bay samples. FDOM components 1, 2, 3, and 5 have been positively identified as humic substance, diesel, tryptophan and tyrosine respectively, using standards. A method was also developed to determine the concentration of identified components in mixed samples. The ability to decompose specific fluorescent signatures has the potential to allow the determination of the sources of FDOM in natural waters provided each source has a unique mix of fluorescent components. This work demonstrates that EEMs coupled
Dombroski, Jessica, "Determining Components of Fluorophoric DOM in Narragansett Bay Using Fluorescence EEMs and PARAFAC" (2004). Open Access Master's Theses. Paper 2078.