Accomplishment Based Renewal (ABR): Pyrite, metal sulfide and aluminosilicate nanoparticles as kinetically stable sources of iron and other metals to the ocean

基于成就的更新（ABR）：黄铁矿、金属硫化物和铝硅酸盐纳米颗粒作为海洋中铁和其他金属的动力学稳定来源

• 批准号: 1558712
• 负责人: George Luther
• 金额: $ 45.97万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558712&HistoricalAwards=false
• 关键词: Accomplishment; Based; Renewal; ABR; Pyrite

Deep-sea hydrothermal vents are sources of soluble metals to the deep ocean. Research in the Atlantic and Pacific Oceans has shown that these dynamic systems are responsible for increases in dissolved iron concentrations up to 4000 kilometers away from where the vents are located. Previous work has shown that up to 11% of the iron released from seafloor hydrothermal vents exists as pyrite nanoparticles (i.e., particles that can pass thorough a 200 nanometer filter). This nano-pyrite, which has a slow oxidation rate in seawater, and its oxidation products can account for the observed increase in dissolved iron in deep ocean waters. This results in enhanced primary biological productivity because iron is an essential micronutrient for bacteria and plankton upon which larger marine organisms feed. Iron, potassium, magnesium and manganese also get incorporated into nano-sized silicates and aluminosilicates as well as larger solid mineral phases, an example of reverse weathering. This research involves both field and laboratory components that examine the production and impact of nano-sulfides and other minerals on the deep ocean iron budget. The field component involves measuring the extent to which nanoparticle-sized pyrite and other metal sulfide phases emanate from seafloor hydrothermal vents on the East Pacific Rise, a fast spreading mid-ocean ridge hydrothermal center. Results of the chemical and physical analysis of these samples, as well as laboratory experiments, onshore, that grow and perform experiments with synthetic analogs of these phases will explore whether copper-sulfur nanoparticulate phases are seed crystals for the formation of nanoparticulate pyrite and other nano-sized phases. It will also examine the process of reverse weathering, which is how silicate and aluminosilicate nanoparticles form and react when hot metal-rich hydrothermal vent waters interact with cold seawater on the ocean floor, something that occurs within the first couple of meters of the vent orifice. Broader impacts of the work include postdoctoral and graduate and undergraduate student training; support of research at an institution in a state (Delaware) that does not receive significant amounts of federal funding (i.e., an EPScoR state); and public outreach via a dedicated website for the oceanographic research cruise on which a K-12 teacher will attend and produce cruise and research related materials targeted to middle and high school students. Public outreach via the University of Delaware's Coast Day which attracts over 10,000 people will be carried out to transmit the excitement and value of the research. This research examines both natural and synthetic materials. Natural materials will come from hydrothermal vents located at 9-10 degrees north latitude in the central Pacific Ocean; and synthetic analog materials, for which various chemical parameters such as pH, sulfide, and metal concentrations, will be generated onshore in the laboratory. All particles will undergo, at a minimum, four types of analyses: analysis of the Fe and sulfide content; analysis of trace metals; and scanning and transmission electron microscopic and energy dispersive chemical compositional analysis. Natural samples will be collected from fluids filtered from hydrothermal vents with trace-metal-clean titanium samplers. Upon retrieval of the natural samples, pH will be measured and samples will be filtered in an argon filled glove bag. Samples will be analyzed in triplicate via inductively coupled plasma mass spectrometry for bioactive metals like Fe, Cu, Zn, Mn, Ni, Cd, and Pb. Individual particles will be examined under the transmission and scanning electron microscopes to determine their morphology and mineral structural characteristics and sizes. Synthetic analogs to the natural materials will be generated in the lab by reacting solutions of FeS and H2S with Cu at temperatures from 20 to 150 C. These will also undergo the same analyses as the natural samples with results of the comparison being used to better understand the formation and reactivity of hydrothermal vent originated nanoparticles in the ocean.

深海水热通风孔是深海可溶金的来源。在大西洋和太平洋的研究表明，这些动态系统负责增加距离通风口所在地4000公里的溶解铁浓度。先前的工作表明，从海底水热释放的铁中最多有11％作为黄铁矿纳米颗粒（即，可以通过200纳米滤波器的颗粒）。这种纳米黄铁矿在海水中的氧化速率缓慢，其氧化产物可以解释深海水中观察到的溶解铁的增加。这导致了一级生物生产力的增强，因为铁是细菌和浮游生物的必不可少的微量营养素，较大的海洋生物会供喂养。铁，钾，镁和锰还将其掺入纳米大小的硅酸盐和铝硅酸盐以及更大的固体矿物相中，这是反向风化的一个例子。这项研究涉及野外和实验室组件，它们检查了纳米硫化物和其他矿物质对深海铁预算的生产和影响。该田间成分涉及测量纳米颗粒大小的黄铁矿和其他金属硫化物相，从东太平洋上升的海底热液中散发出的含量，这是一个快速扩散的中山山脊中心水热中心。这些样品的化学和物理分析以及在陆上进行的实验性实验，这些实验与这些阶段的合成类似物生长和执行实验的结果将探讨铜硫纳米核酸阶段是否是形成纳米含量的含量的种子晶体。它还将检查反向风化的过程，这是硅酸盐和铝硅酸盐纳米颗粒的形成并反应，当热金属富含水热的水热水域与海底的冷海水相互作用，这是在通风口孔的前几米内发生的。这项工作的更广泛影响包括博士后，研究生和本科生培训；在一个州（特拉华州）的机构的研究支持未获得大量联邦资金（即EPSCOR国家）的支持；和通过专门的海洋研究巡游网站进行公共宣传，K-12老师将在该网站上参加并生产针对中学生和高中生的巡航和研究相关材料。通过特拉华大学的沿海日，公众推广将吸引10,000多人，以传达研究的兴奋和价值。这项研究研究了天然和合成材料。天然材料将来自中太平洋北纬9-10度的水热通风孔。以及合成的模拟材料，将在实验室陆上生成各种化学参数，例如pH，硫化物和金属浓度。所有颗粒将至少进行四种类型的分析：FE和硫化物含量的分析；痕量金属分析；以及扫描和透射电子显微镜和能量色散化学成分分析。 天然样品将从带有痕量金属清洁钛样本的水热通风口过滤的流体中收集。回收天然样品后，将测量pH值，并将样品在氩气填充的手套袋中过滤。样品将通过电感耦合等离子体质谱分析样品，以用于Fe，Cu，Cu，Zn，Mn，Ni，CD和PB等生物活性金属。将在传输和扫描电子显微镜下检查各个颗粒，以确定其形态和矿物结构特征和尺寸。实验室将在20至150 C下与Cu的溶液与CU的溶液在实验室中产生合成类似物。这些分析也将与天然样品进行相同的分析，并与比较的结果进行比较的结果，以更好地理解海洋中水热纳米颗粒的形成和反应性。