Collaborative Research (OSU, USC, UCR):Continental Shelf Diagenesis: The Importance of Fresh Continental Material Degradation and Seasonal Diagenesis to Coastal Iron Supply

主导陆架海床的氧化还原反应起着动员或隔离生物必需元素的作用。然而，对于导致这种特定铁源的输送速率或成岩边界条件，人们所知的信息相对较少。因此，很难预测区域水文循环和风化变化如何影响未来应对全球气候变化的沿海铁输送率，也很难量化沿海缺氧增加（或减少）如何影响铁供应。出于这个原因，俄勒冈州立大学、南加州大学和加州大学河滨分校的研究人员将确定以河流为主的小型大陆架沉积物中的铁的成岩输送速率（流出量）。他们将评估新鲜大陆物质的成岩作用是否是向东北太平洋沿岸上升流系统输送生物可利用铁的必要过程，以及底栖生物成岩作用产生的铁的同位素特征是否与其他铁源不同。研究的第一部分将是评估在上升流季节之前、期间和之后，细粒度河流陆架沉积物中底栖生物的铁外溢。第二个组成部分将是测试成岩改变的陆生铁的想法，它在沉积物中经历了多次氧化还原反应，具有独特的同位素特征。如果这是真的，那么铁同位素将被证明是一种有价值的陆架衍生铁的示踪剂，陆架衍生铁被假设为贯穿太平洋盆地大部分地区的重要铁来源。除了这项工作的智力价值外，这项研究还将加强与英国南安普敦国家海洋学中心的同事和一名研究生的合作，他们正在南大西洋进行类似的研究（CROZEX）。作为该项目的一部分，俄勒冈州立大学的两名本科生和南加州大学的一名研究生和一名本科生将得到支持和培训。

ABSTRACTOCE-0624777OCE-0624443OCE-0624704The oxidation-reduction reactions that dominate the shelf seabed act to mobilize or sequester biologically essential elements. However, relatively little information is known about the delivery rates or diagenic boundary conditions that lead to this specific iron source. Thus, it is difficult to predict how changes in the regional hydrological cycle and weathering might impact future coastal iron delivery rates in response to global climate change, as well as quantify how increases (or decreases) in coastal hypoxia influence iron supply. For this reason, researchers at Oregon State University, the University of Southern California, and the University of California-Riverside will determine the diagenetic delivery rate (effux) of iron from small river-dominated continental shelf sediments deposits. They will assess whether or not diagenesis of fresh continental material is an essential process for delivering bio-available iron to the Northeast Pacific coastal upwelling system, and if the isotopic signature for iron that is derived from benthic diagenesis is distinct from other iron sources. The first part of the study will be to evaluate the benthic efflux of iron in fine-grained river-derived shelf deposits prior to, during, and after the upwelling season. The second component will be to test the idea that diagenetically altered terrestrial iron, which has undergone multiple oxidation-reduction reactions within sediments, has a unique isotope signature. If true, iron isotopes could then prove to be a valuable tracer for shelf-derived iron, which has been hypothesized to be an important source of iron throughout much of the Pacific basin. In addition to the intellectual merit of this work, this study will strengthen collaboration with colleagues and a graduate student from the National Oceanographic Center in Southampton, United Kingdom, whom are working on a similar study in the South Atlantic (CROZEX). Two undergraduate students from Oregon State University and one graduate and one undergraduate student from the University of Southern California will be supported and trained as part of this project.