Collaborative Research: Nanoscale Investigations of Marine Organic Matter Diagenesis

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ABSTRACTOCE-0221295OCE-0221029OCE-0221336Investigation of the chemical structures of the uncharacterized fraction of marine dissolved organic matter remains an elusive goal for marine organic chemists. An approach to be used in this work is to directly address supramolecular size scales of marine organic matter structures by assessing their microheterogeneity on micro to nanoscales. Using Scanning Transmission X-ray Microscopy (STXM), a technique that allows the registration of Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra, will allow the quantification of the relative abundance of different functional groups and element bonding types. This spatial mapping of the chemistry of macromolecular assemblages at scales intermediate between bulk chemical analysis and analysis individual molecules or molecular classes offers the capabilities of a important new analytical tool to marine chemistry. In a survey mode, a range of organic materials collected and contributed by several researchers from different parts of the world's oceans will be examined using these techniques. This approach will be extended with additional samples of collected sediment and suspended (trapped) particulates. Laboratory experiments using whole phytoplankton and bacterial cultures will be used to provide materials appropriate to the earlier stages of organic matter diagenesis.