SGER: New Scales of Measuring Organic Carbon Diagenesis in Marine Sediments

南加州大学的一位首席研究员将利用两项前沿技术对海底有机碳循环进行研究。最初，PI将利用基因工程细菌(Shewanella sp.)创建氧气分布。它可以被修饰以使用氧或锰氧化物或电子受体的任何组合来执行碳氧化。使用这些细菌将允许PI构建氧分布，并控制有机底物类型/分布、氧化剂可用性/分布和细菌群落丰度/分布。这项研究的目的是提供在沉积物中观察到的溶质剖面与进行氧化还原反应以产生给定剖面所需的细菌的类型和数量之间的直接关系。此外，PI还将与一位来自德国的科学家合作，使用一台剖面式X射线荧光扫描仪，以2-3毫米的间隔或3-6年的分辨率测定南加州和墨西哥附近低氧地点的层状沉积物中的铁、钙、锰和钛。这项研究的目的是获得铁、锰、钛和碳酸盐固相随时间变化的高分辨率图像，以确定成岩前沿并解释海洋生产力的变化。

AbstractOCE-0129555A principal investigator from the University of Southern California will take advantage of two cutting-edge technologies for an investigation of benthic organic carbon cycling. Initially, the PI will create oxygen profiles utilizing genetically engineered bacteria (Shewanella sp.) which can be modified to perform carbon oxidation using either oxygen, or manganese oxide, or any combination of electron acceptors. Using these bacteria will allow the PI to construct oxygen profiles with control over organic substrate type/distribution, oxidant availability/distribution and bacterial community abundance/distribution. The goal of this research is to provide a direct relationship between solute profiles observed in sediments and the type and abundance of bacteria needed to carry out the redox reactions to yield a given profile. In addition, the PI also will use a profiling X-ray fluorescence scanner in collaboration with a scientist from Germany, to determine Fe, Ca, Mn and Ti in laminated sediments from low-oxygen-sites off Southern California and Mexico at 2-3 mm intervals or 3-6 years of resolution. The objective of this study is to obtain high resolution images of changes in solid phase Fe, Mn and Ti and carbonate as a function of time to identify diagenetic fronts and interpret changes in ocean productivity.