The influence of Fe on the distribution and kinetic speciation of Zn, Cd, Co and Ni in the Southern Ocean

铁是南大洋重要的限制性营养元素，对浮游植物的繁殖和常量营养元素的生物地球化学具有重要的控制作用。然而，其他关键的微量生物元素（Cd、Co、Ni和Zn）也可能影响南大洋浮游植物的次生生产力。这项工作的核心将是在南大洋铁可用性的背景下调查这些生物元素的分布和物种。主要的现场工作将在北极星ANTXXIV-3 ZERO&DRAKE期间进行，作为IPY项目GEOTRACES的一部分。在这次巡航中，Cd, Co， Ni和Zn的形态和分布将在海水中的铁浓度/生物利用度梯度中进行检查；从沿着本初子午线的开阔海域，威德尔海和德雷克海峡到南极岛屿附近。实验室工作将集中于这些元素在南大洋水域环境温度下形成的动力学方面。这项工作将使用最先进的技术进行：(1)竞争性配体交换与阴极溶出伏安法检测，用于测量Co2+， Ni2+动力学和形态。(2)阳极溶出伏安法测定Cd2+和Zn2+的动力学和形态。(3)流动注射化学发光法测定南大洋水域Co含量。(4)测定海水中Co、Ni、Cd、Zn的石墨炉雾化溶剂萃取标准方法。积累的数据将被纳入南大洋微量金属生物地球化学综合模型。

Iron is the key limiting nutrient in the Southern Ocean and has a strong control on phytoplankton productivity and macronutrient biogeochemistry. However there are other key trace bio-elements (Cd, Co, Ni and Zn) which also may influence secondary aspects of phytoplankton productivity in the Southern Ocean. Central to this work will be investigations into the distribution and speciation of these bio-elements in the context of iron availability in the Southern Ocean. The principal field work will be carried out during Polarstern ANTXXIV-3 ZERO&DRAKE as part of the IPY project GEOTRACES. During this cruise the speciation and distribution of Cd, Co, Ni and Zn will be examined across gradients of iron concentration/bioavailabilty in seawater; ranging from an open ocean region along the prime meridian, the Weddell Sea and Drake Passage and near to Antarctic islands. Laboratory work will focus on kinetic aspects of the speciation of these elements at the ambient temperatures found in Southern Ocean waters. The proposed work will be performed using state of the art techniques: (1) Competitive ligand exchange with detection by cathodic stripping voltammetry for the measurement of Co2+, Ni2+ kinetics and speciation. (2) Anodic stripping voltammetry for the measurement of Cd2+ and Zn2+ kinetics and speciation. (3) Flow injection analysis with chemiluminescence detection for the measurement of Co in Southern Ocean waters. (4) Standard solvent extraction methods with graphite furnace atomisation for the measurement of Co, Ni, Cd and Zn in seawater. The accumulated data will be incorporated into a comprehensive model for trace metal biogeochemistry in the Southern Ocean.