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

主宰陆架海底的氧化-还原反应起着动员或隔离生物必需元素的作用。然而，关于导致这一特定铁源的传递率或成岩边界条件的信息相对较少。因此，很难预测区域水文循环和风化的变化如何影响未来沿海铁的输送速率以应对全球气候变化，也很难量化沿海低氧的增加(或减少)如何影响铁的供应。为此，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铁的成岩传送率(EFUX)。他们将评估新鲜大陆物质的成岩作用是否是将生物可利用铁输送到东北太平洋沿岸上升流系统的关键过程，以及来自海底成岩作用的铁的同位素特征是否与其他铁源不同。这项研究的第一部分将评估在上升流季节之前、期间和之后细粒河流陆架沉积中铁的底栖生物外流。第二个部分将测试成岩作用改变的陆地铁具有独特的同位素特征的想法，这些铁在沉积物中经历了多次氧化还原反应。如果是真的，那么铁同位素可能会被证明是陆架来源铁的宝贵示踪剂，而陆架来源的铁被假设为太平洋盆地大部分地区的重要铁源。除了这项工作的学术价值外，这项研究还将加强与同事和联合王国南安普敦国家海洋学中心的一名研究生的合作，他们正在南大西洋(CROZEX)进行类似的研究。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毕业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.