Supply of soluble Fe to ocean surface waters - quantitative approaches from ICDP site Hawaii by determining interface driven Fe transfer from subsurface volcanic rocks

向海洋表层水供应可溶性铁 - 来自夏威夷 ICDP 地点的定量方法，通过确定界面驱动的地下火山岩铁转移

• 批准号: 290773199
• 负责人: Professor Dr. Harald Behrens
• 金额: --
• 依托单位: Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/290773199?language=en
• 关键词: Supply; soluble; Fe; ocean; surface; Supply; soluble; Fe; ocean; surface

Fe as a key limiting micro-nutrient for phytoplankton growth in the surface ocean has impact on the global C cycle. Volcanic rocks are thought to have a marked contribution to the Fe budget in some parts of the oceans, but for quantification of the effect, as stated in a recent review (Ayris & Delmelle, 2012), knowledge on the complex interface driven mechanisms of Fe release/solubility is too limited. In particular the understanding how microbial activity works to release Fe is poor. Inventories on soluble Fe in the surface ocean show marked increases in the vicinity of Hawaii and other volcanic islands. Samples from ICDP site HSDP2 are an archive for different almost fresh to altered subsurface volcanic rocks from hyaloclastites, lava flows and pillow basalts. Thus, these samples are excellently suited for the detection of relevant mechanisms of Fe release at the solid-liquid interface, modes of Fe solubility and quantitative approaches on this process. In the first year suitable samples were selected based on different criteria such as type of rock, age, degree of alteration, fresh- or seawater influenced and temperature. Quantification of four different secondary Fe binding forms in core samples was done using a sequential extraction procedure. A colorimetric wet-chemistry method was used to quantify Fe(II) and total Fe. Fe transfer from core samples to a soluble form induced by the bacterium Burkholderia fungorum was investigated in microbiological experiments. Colonization experiments with fresh synthetic basaltic glasses were performed which show a strong promoting effect of strain and ferrous iron on biological activity. Ionic effects on the chemistry of the solid-liquid interface of basaltic glass during alteration traced by measurements of the zeta potential and determination of the specific surface area (SSA) of samples from laboratory experiments as well as core samples are planned for the second year of the first proposal.In the third year, for which funding is requested here, we want to study porosity and pore connectivity in the rock samples by T-dependent water-release, Woods metal intrusion and penetration. Tomographic studies and Raman spectroscopy will provide additional information on pore distribution and phase abundance. Additionally, the measurement of water-release in function of temperature will yield data about contents of secondary minerals. Influence of various parameters (solution composition, strain in glasses, redox state of iron) on bacterical colonization will be studied using XPS, ESEM and Laser microscopy. Combining the different findings with literature data will improve our understanding of interdependencies of mineralogical composition, solution composition, biochemical factors and alteration rates on release of soluble Fe.

FE作为地表海洋浮游植物生长的主要限制微营养素会影响全球C周期。人们认为火山岩在海洋某些地区对FE预算有明显的贡献，但是对于量化效应的量化，如最近的综述（Ayris＆Delmelle，2012年）所述，有关FE释放/溶解度的复杂接口驱动机制的知识过于限制。特别地，了解微生物活性如何释放Fe是很差的。夏威夷和其他火山群岛附近的地面海洋可溶性FE的库存标志着增加。来自ICDP站点HSDP2的样品是一个档案馆，用于不同的几乎新鲜到改变的地下火山岩，来自透视岩，熔岩流和枕头玄武岩的档案。因此，这些样品非常适合在固液界面，FE溶解度模式和此过程中的定量方法上检测相关的Fe释放机制。在第一年，根据不同的标准选择合适的样品，例如岩石类型，年龄，改变程度，新鲜或海水受到影响和温度。使用顺序提取程序对核心样品进行了四种不同的二级Fe结合形式的定量。使用比色化学方法来量化Fe（II）和总Fe。在微生物实验中研究了FE从核心样品转移到由Burkholderia真菌诱导的可溶性形式的转移。进行了新的合成玄武岩玻璃的定植实验，该玻璃表现出菌株和铁铁对生物学活性的强烈促进作用。 Ionic effects on the chemistry of the solid-liquid interface of basaltic glass during alteration traced by measurements of the zeta potential and determination of the specific surface area (SSA) of samples from laboratory experiments as well as core samples are planned for the second year of the first proposal.In the third year, for which funding is requested here, we want to study porosity and pore connectivity in the rock samples by T-dependent water-release,伍兹金属侵入和穿透。层析成像研究和拉曼光谱法将提供有关孔隙分布和相丰度的其他信息。另外，在温度功能方面释放释放的测量将产生有关二级矿物质内容物的数据。将使用XPS，ESEM和激光显微镜研究各种参数（溶液组成，玻璃中的应变，氧化还原状态）对细菌定植的影响。将不同的发现与文献数据相结合将提高我们对矿物组成，溶液组成，生化因素和可溶性FE释放的变化率的相互依赖性的理解。