Collaborative Proposal: Assessment of the Colloidal Iron Size Spectrum in Coastal and Oceanic Waters

合作提案：沿海和海洋水域中胶体铁粒径谱的评估

• 批准号: 1435021
• 负责人: Mark Wells
• 金额: $ 26.93万
• 依托单位: University of Maine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1435021&HistoricalAwards=false
• 关键词: Collaborative; Proposal; Assessment; Colloidal; Iron

Bioavailable iron is arguably the most important nutrient for shaping the distribution and composition of marine primary productivity and, in turn, the magnitude of ocean carbon export. Iron exists in many phases throughout the world's oceans, and colloidal, or non-soluble, phases comprise a significant fraction of dissolved iron. However, the size and physical/chemical character of these phases is presently poorly understood. To better understand this key part of iron cycling, researchers will use new analytical chemistry methods to quantitatively separate the colloidal iron sizes present in a sample and measure the composition of these colloidal portions in shelf and oceanic waters. Results from this study will help hone future studies to better link the source and fate of iron in the marine environment. A postdoctoral researcher will serve as a principal investigator on the project, providing a unique professional development opportunity. In addition, the project will support the education and research training of one undergraduate student each year, and the researchers will conduct outreach activities to K-12 students and teachers.The colloidal phase of iron may serve as a biological source of stored iron, a primary conveyance for stripping iron into sinking particulate matter (removing it from the pelagic biosphere), or, more likely, a dynamic balance of these roles that fluctuates with the source and character of iron input. The current methods to investigate marine colloidal matter involve operationally defining the bulk colloidal phase using single cutoff filters, a practical decision based on little or no evidence. More problematic, these methods homogenize the colloidal phase, obscuring what almost certainly is a reactivity spectrum of colloidal species tied to their size and compositional character. In this study, the researchers will use Flow Field-Flow Fractionation coupled to Multi-Angle Laser Light Scattering to make measurements of the uniformity or uniqueness of the colloidal size spectrum, and the physical/chemical character of these phases. The findings will have broad implications to the fields of marine ecology and biogeochemistry and, ultimately, to modeling studies of ocean-atmospheric coupling and climate change.

可以说，生物利用的铁是塑造海洋初级生产力的分布和组成的最重要的营养素，进而是海洋碳出口的幅度。铁在世界海洋中的许多阶段存在，胶体或非溶性阶段包含很大一部分溶解的铁。但是，目前对这些阶段的大小和物理/化学特征的了解很差。为了更好地理解铁循环的这一关键部分，研究人员将使用新的分析化学方法来定量分离样品中存在的胶体铁尺寸，并测量架子和海洋水域中这些胶体部分的组成。这项研究的结果将有助于磨练未来的研究，以更好地联系海洋环境中铁的来源和命运。博士后研究人员将担任该项目的首席研究员，提供独特的专业发展机会。此外，该项目将支持每年一名本科生的教育和研究培训，研究人员将向K-12学生和老师进行外展活动。铁的胶体阶段可以作为储存铁的生物学来源，是将铁剥离到颗粒物中的主要输送（将其从颗粒物中降低（将其从pelagic Bioperperie中删除），或者更可能是富于这些动态的，这些属性是在这些动态的平衡。当前研究海洋胶体物质的方法涉及使用单个截止过滤器在操作上定义块状胶体相，这是基于几乎没有证据的实际决定。这些方法更有问题，使胶体相均匀，从而掩盖了与其大小和组成特征相关的胶体物种的反应性谱。在这项研究中，研究人员将使用与多角度激光散射结合的流场分级分馏来测量胶体大小谱的均匀性或唯一性，以及这些相的物理/化学特征。这些发现将对海洋生态学和生物地球化学领域具有广泛的影响，并最终对对海洋 - 大气耦合和气候变化的研究进行建模。