(Table 2) Zinc complexation data from POLARSTERN cruise ANT-XXIV/3

The speciation of dissolved zinc (Zn) was investigated by voltammetry in the Atlantic sector of the Southern Ocean along two transects across the major frontal systems: along the Zero Meridian and across the Drake Passage. In the Southern Ocean south of the APF we found detectable labile inorganic Zn throughout the surface waters in contrast to studies from lower latitudes. Using a combination of ASV titrations and pseudopolarography revealed the presence of significant concentration of electrochemically inert Zn ligands throughout the Southern Ocean. These ligands however were nearly always saturated due to the presence of excess concentrations of dissolved Zn that were associated with the high nutrient waters south of the Antarctic Polar Front (APF). Only in surface waters did the concentration of Zn complexing ligands exceed the dissolved Zn concentrations suggesting a biological source for these ligands. Our findings have clear implications for the biogeochemical cycling of Zn and for the interpretation of paleo records utilizing Zn in opal as a tracer of Zn speciation in the water column.本研究采用伏安法，对南大洋大西洋扇区两条横跨主要锋面系统的断面（沿本初子午线、横跨德雷克海峡）中的溶解态锌（Zn）形态分布开展了调查。在南极极锋（Antarctic Polar Front, APF）以南的南大洋海域，我们在全部表层水体中均检测到了活性无机锌，这与低纬度海域的相关研究结果形成鲜明对比。结合阳极溶出伏安法（ASV）滴定与假极谱法的分析结果显示，整个南大洋海域广泛存在大量电化学惰性锌配体。但由于南极极锋以南高营养盐水体中溶解态锌浓度过高，这些配体几乎始终处于饱和状态。仅在表层水体中，锌络合配体的浓度才超过溶解态锌浓度，暗示这类配体可能具有生物来源。本研究结果对锌的生物地球化学循环研究，以及以蛋白石中的锌作为水柱锌形态示踪剂的古环境记录解译工作，均具有明确的指导意义。