The distribution of zinc, cadmium, copper and iron in seawater of the Iceland-Faroe Ridge area

During the International ICES Expedition "Overflow '73" a total of 174 samples from 18 stations were collected by R. V. "Meteor" in the waters of the Iceland-Faroe Ridge area. They were filtered on board ship (through 0.4 mym "Nuclepore" filters), then stored in 500 cm**3 quartz bottles (at -20 °C) and analyzed in air-filtered laboratories on land for zinc and cadmium by means of the differential pulse anodic stripping voltammetry technique and copper and iron by flameless atomic absorption spectrometry. The overall averages of 1.9 myg Zn l**-1, 0.07 myg Cd l**-1, 0.5 myg Cu l**-1 and 0.9 myg Fe l**-1 are in good agreement with recent "baseline" studies of open-ocean waters. The mixture of low salinity water masses from the North Iceland Shelf/Arctic Intermediate Waters seem to maintain distinctly lower concentration of Cd, Cu and Fe than the waters from the North Atlantic and the Norwegian Sea where quite similar mean values are found. There is only little evidence for the assumption that overflow events on the ridge are influencing the concentrations of dissolved metals in the near-bottom layers.

在国际海洋考察理事会（ICES）"Overflow ’73"考察航次期间，"流星号"（R/V Meteor）研究船在冰岛-法罗海脊海域共计采集了18个站位的174份样品。样品在船上通过0.4 μm Nuclepore滤膜进行过滤，随后储存于500 cm³石英瓶中并置于-20 ℃环境下保存；后续在陆地空气净化实验室内，采用差分脉冲阳极溶出伏安法测定锌（Zn）与镉（Cd）的含量，采用无火焰原子吸收光谱法测定铜（Cu）与铁（Fe）的含量。本次检测得到的总体平均浓度分别为：锌1.9 μg·L⁻¹、镉0.07 μg·L⁻¹、铜0.5 μg·L⁻¹、铁0.9 μg·L⁻¹，该结果与近期开阔大洋水体的"基线"研究数据吻合度较高。源自冰岛北部陆架/北极中层水的低盐水团混合体，其镉、铜与铁的浓度显著低于北大西洋与挪威海海域水体；后两者的溶解态金属平均含量较为相近。目前仅有少量证据支持海脊溢流事件会对近底层水体中的溶解态金属浓度产生影响这一假说。