Collaborative Research: Nanoscale Investigations of Marine Organic Matter Diagenesis

海洋溶解有机物中未表征部分的化学结构的研究仍然是海洋有机化学家难以实现的目标。在这项工作中使用的一种方法是直接解决海洋有机物结构的超分子尺寸尺度，通过评估其微观到纳米尺度的微观异质性。使用扫描透射X射线显微镜（STXM），一种允许近边X射线吸收精细结构（NEXAFS）光谱登记的技术，将允许量化不同官能团和元素键合类型的相对丰度。这种大分子组合物化学性质的空间测绘介于整体化学分析和分析单个分子或分子类别之间，为海洋化学提供了一种重要的新分析工具。在调查模式下，将利用这些技术对若干研究人员从世界各大洋不同地区收集和提供的一系列有机材料进行研究。这一方法将扩展到收集到的沉积物和悬浮（捕获）颗粒物的额外样本。利用整个浮游植物和细菌培养物的实验室实验将用于提供适合于有机质成岩作用早期阶段的材料。

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.