Organic complexation of copper in deep-sea hydrothermal vent systems
Organic complexation of copper in deep-sea hydrothermal vent systems
复制标题
深海热液喷口系统中铜的有机络合
DOI：
10.1071/en06086
复制
发表时间：
2007
影响因子：
4.3
通讯作者：
K. Hunter
中科院分区：
文献类型：
--
作者：
S. Sander;A. Koschinsky;G. Massoth;M. Stott;K. Hunter
环境背景。深海热液喷口是许多极端生物的自然栖息地，能够应对极端的物理和化学条件，包括高负荷的重金属和减少的气体。到目前为止，还没有关于这些系统中金属有机络合的水平和作用的信息，这将对金属的生物有效性和沉淀或矿化产生影响。在这项工作中，我们提供了包括硫醇在内的有机分子的存在的证据，这些有机分子能够与铜形成络合物，其强度足以与水热体系中高水平存在的硫化物竞争。抽象的。本文首次报道了在热液喷口系统中，包括中温出口、与邻近热液生物群落的扩散喷口以及与海水的局部混合区在内的热液喷口系统中，强烈的有机络合作用对铜的化学形态具有重要作用。来自三个深海热液喷口地区的样品显示，有机铜结合配体的浓度范围很广，最高可达4,000 nm，具有非常高的条件稳定常数(对数 K‘Cul=12.48至13.46)。通常在周围海水条件下(pH 7.8)去除硫化物后使用伏安法进行测量，但在pH 4.5和2.1时仍会发生结合。我们的水热样品的伏安行为与谷胱甘肽(GSH)的伏安行为进行了比较，谷胱甘肽(GSH)是一种已知的强铜结合配体，它是有机硫醇的代表。我们的结果为包括硫醇在内的有机配体的存在提供了令人信服的证据，这些有机配体形成的络合物足够强大，足以在控制热液喷口周围金属离子的生物有效性和地球化学行为方面发挥重要作用。
Environmental context. Deep-sea hydrothermal vents represent a natural habitat for many extremophile organisms able to cope with extreme physical and chemical conditions, including high loads of heavy metals and reduced gases. To date, no information is available on the level and role of organic complexation of metals in these systems, which will have consequences on the bioavailability and precipitation or mineralisation of metals. In this work, we give evidence for the presence of organic molecules, including thiols, capable of forming complexes with copper strong enough to compete against sulfide present at high levels in hydrothermal systems. Abstract. Here we report, for the first time, that strong organic complexation plays an important role in the chemical speciation of copper in hydrothermal vent systems including medium temperature outlets, diffuse vents with an adjacent hydrothermal biocommunity, and local mixing zone with seawater. Samples from three deep-sea hydrothermal vent areas show a wide concentration range of organic copper-binding ligands, up to 4000 nM, with very high conditional stability constants (log K′Cu′L = 12.48 to 13.46). Measurements were usually made using voltammetric methods after removal of sulfide species under ambient seawater conditions (pH 7.8), but binding still occurs at pH 4.5 and 2.1. The voltammetric behaviour of our hydrothermal samples is compared with that of glutathione (GSH) a known strong Cu-binding ligand, as a representative of an organic thiol. Our results provide compelling evidence for the presence of organic ligands, including thiols, which form complexes strong enough to play an important role in controlling the bioavailability and geochemical behaviour of metal ions around hydrothermal vents.