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

基本信息

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

项目摘要

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 作为海洋表层浮游植物生长的关键限制性微量营养素，对全球碳循环产生影响。火山岩被认为对海洋某些部分的铁预算有显着贡献，但为了量化其影响，正如最近的一篇评论（Ayris & Delmelle，2012）所述，关于铁的复杂界面驱动机制的知识释放/溶解度太有限。特别是对微生物活动如何释放铁的了解还很薄弱。夏威夷和其他火山岛附近海洋表层可溶性铁的库存量显着增加。来自 ICDP 站点 HSDP2 的样本是来自透明碎屑岩、熔岩流和枕状玄武岩的各种几乎新鲜到蚀变的地下火山岩的档案。因此，这些样品非常适合检测固液界面铁释放的相关机制、铁溶解度模式以及该过程的定量方法。第一年，根据岩石类型、年龄、蚀变程度、淡水或海水影响以及温度等不同标准选择合适的样本。使用顺序提取程序对岩心样品中四种不同的次级铁结合形式进行定量。使用比色湿化学方法定量 Fe(II) 和总 Fe。在微生物实验中研究了真菌伯克霍尔德氏菌诱导铁从岩心样品转移到可溶形式的过程。用新鲜的合成玄武岩玻璃进行定植实验，结果表明菌株和二价铁对生物活性有很强的促进作用。计划在第二年通过测量实验室实验样品以及岩心样品的 zeta 电位和确定比表面积 (SSA) 来追踪玄武岩玻璃固液界面化学变化过程中的离子效应。第一个提案。在第三年，这里需要资金，我们希望通过 T 相关的水释放、伍兹金属侵入和渗透来研究岩石样品中的孔隙度和孔隙连通性。断层扫描研究和拉曼光谱将提供有关孔隙分布和相丰度的更多信息。此外，测量随温度变化的水释放量将产生有关次生矿物质含量的数据。将使用 XPS、ESEM 和激光显微镜研究各种参数（溶液成分、玻璃应变、铁的氧化还原状态）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成分、溶液成分、生化因素和可溶性铁释放的变化率之间相互依赖性的理解。