First winter measurements of dissolved zinc (dZn) and particulate zinc (pZn) are presented from seven stations, between 41 and 58°S, occupied in July 2017 along the 30°E longitude in the Indian Sector of the Southern Ocean. This unique spatial and seasonal dataset provided the opportunity to investigate Zn biogeochemical cycling in a region which is extremely data scarce and during a period when conditions are unfavourable for phytoplankton growth. Surface comparisons of our winter dZn and pZn to previous measurements during spring and summer revealed that Zn seasonality is most pronounced at the higher latitudes where higher dZn (and higher ratios of dZn to phosphate; dZn:PO₄) and lower pZn in winter reflect decreased biological uptake and preferential dZn resupply (relative to PO₄) to surface waters through deep winter mixing. The composition of pZn was majorly biogenic however localised lithogenic inputs were attributed to potential hydrothermal activity and transport of continental sediment via Agulhas waters. Calculated vertical attenuation factors (b values) for pZn (0.31) and phosphorus (P; 0.41) suggest that Zn has a longer remineralisation length scale than P, providing a mechanism as to why dZn appears to be remineralised deeper in the water column than PO₄. Ratios of pZn to P (pZn:P) in surface waters increased with latitude from 1.12 to 8.28 mmol mol⁻¹ due to increased dZn availability and the dominance of diatoms (with high cellular Zn quotas) in the high latitude Antarctic Zone (AAZ). Interestingly, the high surface pZn:P ratios in the AAZ did not change significantly with depth (in contrast to the northern stations where pZn:P increased with depth) suggesting the export of diatom cells below the winter mixed layer where remineralisation and rigorous mixing may resolve the linear dZn to silicic acid (dZn:Si(OH)₄) correlation (dZn (nmol kg⁻¹) = 0.064 Si(OH)₄ (μmol kg⁻¹) + 0.690; r² = 0.93; n = 120) despite these elements being located in separate components of the diatom cell. Additionally, elevated concentrations of dZn and Si(OH)₄ below 3000 m in the AAZ may reflect nutrient accumulation in bottom waters where northward flow is inhibited by the Indian mid-Ocean ridge.

2017 年 7 月沿南大洋印度区的 30°E 经度，在 41 至 58°S 之间的七个站点提供了溶解锌 (dZn) 和颗粒锌 (pZn) 的首次冬季测量。这个独特的空间和季节性数据集提供了在一个数据极其稀缺的地区和条件不利于浮游植物生长的时期研究锌生物地球化学循环的机会。我们冬季 dZn 和 pZn 与之前春季和夏季测量结果的表面比较表明，Zn 季节性在高纬度地区最为显着，其中 dZn 较高（以及 dZn 与磷酸盐的比率较高；dZn:PO ₄) 和冬季较低的 pZn 反映了生物吸收减少和通过冬季深层混合对地表水的dZn 优先补给（相对于 PO ₄ ）。pZn 的成分主要是生物成因的，但局部岩源输入归因于潜在的热液活动和大陆沉积物通过 Agulhas 水域的运输。计算出的 pZn (0.31) 和磷(P; 0.41) 的垂直衰减因子（b值）表明 Zn 的再矿化长度尺度比 P 更长，这提供了为什么 dZn 在水体中比 PO 更深的再矿化机制₄ . 地表水中 pZn 与 P 的比率 (pZn:P) 随着纬度从 1.12 增加到 8.28 mmol mol ^-1由于 dZn 可用性的增加和高纬度南极区 (AAZ) 中硅藻（具有高细胞锌配额）的优势。有趣的是，AAZ 中的高表面 pZn:P 比率没有随着深度而显着变化（与 pZn:P 随深度增加的北部站相反）表明硅藻细胞在冬季混合层下方的出口，在那里再矿化和严格混合可能解析线性 dZn 与硅酸 (dZn:Si(OH) ₄ ) 相关性 (dZn (nmol kg ^-1 ) = 0.064 Si(OH) ₄ (μmol kg ^-1 ) + 0.690；r ²  = 0.93；n = 120）尽管这些元素位于硅藻细胞的不同组件中。此外，AAZ中 3000 米以下的 dZn 和 Si(OH) ₄浓度升高可能反映了底水中的营养物质积累，其中印度洋中脊抑制了向北流动。