The Southern Ocean is the largest high-nutrient low-chlorophyll environment in the global ocean, and represents an important source of intermediate and deep waters to lower latitudes. Constraining Southern Ocean trace metal biogeochemical cycling is therefore important not just for understanding biological productivity and carbon cycling regionally, but also for understanding trace metal distributions throughout the lower latitude oceans. We present dissolved Fe, Ni, Cu, Zn, Cd, Pb and macronutrient concentrations in the Indian and Pacific sectors of the Southern Ocean from the Antarctic Circumnavigation Expedition (austral summer 2016-17), which included the first opportunities to study trace metal cycling at the Mertz Glacier Polynya and the Balleny Islands, as well as two meridional cross-frontal transects. Dissolved Ni, Cu, Zn, Cd and macronutrient concentrations show similar or greater variability latitudinally within surface waters than vertically through the water column, reflecting the combined influence of circulation and biological drawdown in shaping the distributions of nutrient-type elements in the Southern Ocean. Slopes of Cu-Si(OH)₄ and Cd-PO₄ increase from the Polar Frontal Zone to south of the Southern ACC Boundary (Cu-Si(OH)₄) and from the Subantarctic Zone to the Antarctic Zone (Cd-PO₄). Latitudinal differences are also observed for Ni-Si(OH)₄ and Zn-PO₄, with distinct Subantarctic Zone trends relative to those south of the Polar Front. Similarities between our Zn-Si(OH)₄ and Cd-PO₄ correlations and global compilations reflect the importance of exported Southern Ocean waters in setting these metal-macronutrient couples globally. Distinct Ni-macronutrient correlations are observed in this dataset relative to the global ocean, which supports a distinct cycling of Ni in the Southern Ocean compared to other basins. Concentrations of Pb are among the lowest observed in the global ocean; however, a local maximum is seen along the density level corresponding with Antarctic Intermediate Water. Concentrations within this isopycnal decrease with increasing latitude, which can be explained by decreasing atmospheric Pb input to more recently subducted waters.

Substantial biological uptake of metals and macronutrients is observed at the Mertz Glacier Polynya. Here, inferred metal:macronutrient uptake ratios are comparable to those found in the Amundsen Sea Polynya, in Southern Ocean phytoplankton, and to metal-macronutrient correlations in our data set as a whole, highlighting the potential of Southern Ocean polynyas as natural systems for trace metal uptake and export studies. The Balleny Islands are a source of Fe to surface waters and the islands also appear to influence distributions of Zn, Cu and macronutrients, which may reflect the combined impact of Fe supply on biological uptake, mixing, and scavenging in deeper waters. The Kerguelen Plateau is also a source of Fe, as previously identified. Throughout our dataset, the ferricline is found deeper than the nitricline, in agreement with existing data and indicating that Fe is less easily entrained into the surface ocean than NO₃. Additionally, Fe:NO₃ ratios in most samples throughout the water column are Fe-limiting (<0.01 mmol mol⁻¹). Therefore deep mixing, identified previously as the main Fe source to much of the Southern Ocean, would ultimately act to maintain Fe limitation.

南部海洋是全球海洋中最大的高营养低叶绿素环境，并且是低纬度地区中深水域的重要来源。因此，限制南大洋的痕量金属生物地球化学循环不仅对于理解区域的生物生产力和碳循环非常重要，而且对于理解整个低纬度海洋中的痕量金属分布也很重要。我们介绍了南极环游探险（2016-17年夏季）在南洋印度洋和太平洋地区溶解的铁，镍，铜，锌，镉，铅和铅和常量营养素的浓度，其中包括首次研究痕量金属循环的机会在Mertz冰川Polynya和Balleny群岛，以及两个子午线横额断面。溶解的镍，铜，锌，镉和常量营养素的浓度在地表水中的纬度变化比在垂直方向穿过水柱的纬度相似或更大，反映了循环和生物沉降对形成南大洋中营养物类型元素分布的综合影响。Cu-Si（OH）的斜率₄和Cd-PO ₄从极额带向南ACC边界以南（Cu-Si（OH）₄）增大，从亚极带向南极带（Cd-PO ₄）增大。还观察到了Ni-Si（OH）₄和Zn-PO _4的纬度差异，相对于极地锋以南的亚南极带趋势不同。Zn-Si（OH）₄和Cd-PO ₄之间的相似性相关性和全球汇编反映了出口南大洋水域在全球范围内设定这些金属-宏营养素对的重要性。相对于全球海洋，在该数据集中观察到了明显的镍-宏营养素相关性，与其他盆地相比，这支持了南部海洋中镍的独特循环。铅的含量是全球海洋中最低的；然而，沿着对应于南极中级水的密度水平可以看到局部最大值。该等密度线内的浓度随纬度的增加而降低，这可以通过减少向较新近俯冲水域的大气Pb输入量的减少来解释。

在Mertz Glacier Polynya观察到大量金属和大量营养素的生物吸收。在这里，推断出的金属：大量养分的吸收率可与在南洋浮游植物的阿蒙森海多生鱼中发现的金属和养分的吸收率相媲美，并且与我们整体数据集中的金属与养分的相关性相当，这突显了南大洋多生菌作为天然痕量系统的潜力金属吸收和出口研究。巴利尼群岛是地表水中铁的来源，这些群岛似乎也影响锌，铜和大量营养素的分布，这可能反映了铁供应对深水生物吸收，混合和清除的综合影响。如前所述，克格伦高原也是铁的来源。在我们的整个数据集中，发现亚铁比硝酸更深，₃。另外，在整个水柱中的大多数样品中的Fe：NO ₃比是Fe限制的（<0.01 mmol mol ^-1）。因此，以前被认为是南大洋大部分地区主要铁源的深度混合最终将维持铁的限制。