Metal-sulfide speciation and cluster formation at deep-sea hydrothermal vents

摘要(0424789)-路德这个项目是为了研究热液喷口的锌(锌)、铁(铁)和硫化物的形态，以及在这些极端环境下金属-硫化物团簇的形成机制。这种方法是基于以前在东太平洋隆起热液喷口观察到的生物群落结构是硫化物和铁形态的函数。硫化物形态的形成预计会影响其他热液喷口地点的生物分布，如刘盆地。在刘盆地东刘扩张中心的喷口流体中检测到了高浓度的锌。由于锌与硫化物的结合速度快于铁，因此锌有望在刘盆地喷口硫化物形态形成中发挥关键作用。在热液喷口周围的水域中，铁和锌等金属可以与硫化物形成团簇。这些可溶簇合物是多核络合物，在微摩尔浓度或更低的浓度下稳定。它们很可能成为颗粒和矿物的积木。由于已在东太平洋隆起喷口测量到FeS星团，因此预计在刘盆地喷口栖息地将形成硫化锌星团。ZNS簇在水环境中特别稳定；然而，关于ZNS簇的形成机制、簇结构和喷口位置的稳定性尚不清楚。需要检验的假设是，在金属-硫化物簇主导硫化物形态的扩散流口附近，化学合成生物不会茁壮成长。为了更好地了解喷口栖息地的金属硫化物形态和生物群落，本项目将集中于以下目标：(1)两个喷口扩散流区硫化物和金属形态的比较；(2)刘盆地喷口群落结构与锌硫化物形态的相关性；(3)决定喷口位置硫化锌团簇结构、稳定性和反应性的物理化学条件。这些目标将通过实地研究和实验室研究相结合来实现。实地研究将集中在东太平洋海隆北纬9°49‘至9°51’范围内的喷口，以及流河盆地华法山脊的喷口。硫化物和金属的形态将通过先前建立的原位伏安法进行测量。为了补充现场观测，一系列实验室研究将试图阐明这些喷口生境中硫化锌星团的形成机制和星团结构。建议进行更多的研究，以调查硫化锌团簇与其他竞争金属和天然有机物的反应性。这项研究将通过促进跨学科研究和合作产生更广泛的影响。该奖学金将为刚接触山脊科学但具有金属硫化物地球化学研究经验的博士后研究员提供一个独特的机会。这项研究还将有助于其他水生系统中金属和硫化物化学的基础知识。这项研究的结果有望对从海洋沉积物到城市废水等各种水生环境中的痕量金属硫化物生物地球化学产生影响。

Abstract (0424789) - LutherThis project for the Ridge 2000 Postdoctoral Fellowship is an investigation of zinc (Zn),iron (Fe), and sulfide speciation at hydrothermal vents and the mechanisms of metal-sulfide cluster formation at these extreme environments. The approach is based on previous observations at hydrothermal vents of the East Pacific Rise that biological community structure is a function of sulfide and Fe speciation. Sulfide speciation is expected to influence the distribution of organisms at other hydrothermal vent locations such as the Lau Basin. High concentrations of Zn have been measured in vent fluid at the East Lau Spreading Center of the Lau Basin. Because Zn binds to sulfide faster than Fe, Zn is expected to play a key role in sulfide speciation at vents in the Lau Basin. In waters surrounding hydrothermal vents, metals such as Fe and Zn can form clusters with sulfide. These soluble clusters are multinuclear complexes that are stable at concentrations of micromolar or lower. They are likely to serve as building blocks for particles and minerals. Because FeS cluster have been measured at East Pacific Rise vents, ZnS clusters are expected to form at Lau Basin vent habitats. ZnS clusters are particularly stable in aquatic environments; however, much remains unknown concerning the mechanisms of ZnS cluster formation, cluster structure and stability at vent locations.The hypothesis to be tested is chemosynthetic organisms do not thrive near diffuse flowvent waters where metal-sulfide clusters dominate sulfide speciation. In order to betterunderstand metal-sulfide speciation and biological communities at vent habitats, this project will focus on the following objectives: (1) comparison of sulfide and metal speciation in vent diffuse flow regions at the two vent locations; (2) correlation between Zn-sulfide speciation and vent community structure at the Lau Basin site, and (3) assessment of physicochemical conditions that determine ZnS cluster structure, stability and reactivity at vent locations. These objectives will be achieved through a combination of field and laboratory studies. Field studies will focus on vents in the area between 9 degrees 49' and 9 degrees 51'N at the East Pacific Rise and vents at the Valu Fa Ridge in the Lau Basin. Sulfide and metal speciation will be measured by previously established in-situ voltammetric methods. To complement field observations, a series of laboratory studies will attempt to elucidate the mechanism of ZnS cluster formation and cluster structure at these vent habitats. Additional studies are proposed to investigate the reactivity of ZnS clusters with other competing metals and with natural organic matter. This research will have broader impacts by fostering interdisciplinary research andCollaborations. The fellowship will provide a unique opportunity to a postdoctoral fellow who is new to ridge crest science but has research experience in metal-sulfide geochemistry. This research will also contribute to fundamental knowledge of metal and sulfide chemistry in other aquatic systems. Outcomes of this research are expected to have implications for trace metal sulfide biogeochemistry in a variety of aquatic environments ranging from marine sediments to municipal wastewater.