Abstract
Dissolved organic matter (DOM) plays a crucial role in the nutrient and carbon cycling in the coastal-shelf-ocean boundary. It is a major reservoir of reduced carbon and carries important information on how the sea and landscape have been modified. Due to the complexity of the biogeochemical processes in this boundary, its distribution is not well understood. This study evaluated the Excitation Emission Matrix (EEM) fluorescence method combined with Parallel Factorial Analysis (PARAFAC) modeling to resolve DOM fluorescence components, and their distribution from near-shore to off-shore. Results of this study demonstrated several advances in monitoring the temporal distribution of DOM on the continental shelf of Florida using EEM and PARAFAC, including the methods application in harmful algal bloom and oil spill studies. This study employed PARAFAC models that were able to: 1) resolve sources of individual components of the bulk DOM from nearshore to the continental margins of southwest Florida; 2) provide insight into the biological, chemical, and physical processes that control the DOM variabilities of each of the resolved DOM components on the Shelf; 3) develop and test the hypothesis that the protein-like fluorescence component supported the October 2011 K. brevis bloom; 4) observe relationship of brevetoxin incorporation in marine sediments enriched with terrestrial DOM; and, 5) simultaneously discriminate residues of the Macondo crude oil components, the dispersants, and dissociate signal related to CDOM in the water column after the Deepwater Horizon oil spill in the Gulf of Mexico.