Surface ocean biogeochemistry and deep ocean circulation control relationships between nutrient-type trace metals (Cd, Ni, Cu, and Zn) and nutrients in the South Atlantic Ocean near the subtropical front
Surface ocean biogeochemistry and deep ocean circulation control relationships between nutrient-type trace metals (Cd, Ni, Cu, and Zn) and nutrients in the South Atlantic Ocean near the subtropical front
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DOI：
10.1016/j.gca.2024.01.001
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发表时间：
2024-01
影响因子：
5
通讯作者：
Xue-Gang Chen;Martha Gledhill;M. Lohan;A. Milne;Eric P. Achterberg
中科院分区：
文献类型：
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作者：
Xue-Gang Chen;Martha Gledhill;M. Lohan;A. Milne;Eric P. Achterberg
南大西洋沿着南纬40°S的海洋区域，以初级生产力增强为特征，形成了富营养但贫铁的南大洋与贫硝酸盐和铁的副热带环流之间的过渡带。在这里，我们提出了营养型溶解和颗粒微量金属（dTM和pTM），包括镉（Cd），镍（Ni），铜（Cu），锌（Zn）在南大西洋的GEOTRACES GA 10巡航分布。浮游植物吸收、河流和大气输入影响了地表沃茨中dTM和pTM浓度（dCd 27.8 ± 36.0 pmol kg−1，n = 222; dCu 0.732 ± 0.429 nmol kg−1，n = 222; dNi 3.38 ± 0.52 nmol kg−1，n = 219; dZn 0.332 ± 0.398 nmol kg−1，n = 214）。地下营养物和dTM（dCd 563 ± 184 pmol kg−1，n = 335; dCu 1.819 ± 0.773 nmol kg−1，n = 334; dNi 6.19 ± 1.06 nmol kg−1，n = 330; dZn 3.71 ± 2.10 nmol kg−1，n = 333）受南极起源沃茨和北大西洋深层沃茨（NADW）混合的控制而本地化的贡献微不足道。阿根廷海盆的溶解和颗粒TM显示，由于底栖生物的输入，向海底的浓度升高。沿着样带未观察到dTM和pTM向深水沃茨的直接热液输入。南极起源沃茨的Cd-Cu-Zn-磷酸盐化学计量学设置的组合的动态物理循环和优先吸收的Cd，Cu，和Zn相对于磷酸盐在表面沃茨，因为占主导地位的硅藻在南大洋。水团混合随后产生回旋dCu-P和dZn-P的关系和明显的线性dCd-P和dNi-P的关系在南大西洋。更重要的是，南极沃茨和NADW的端元特征在很大程度上固定在它们在高纬度海洋的形成区域。因此，高纬海洋是通过温盐环流向低纬海洋提供特定比例的营养盐和TM的关键区域。高纬度海洋过程的变化可能对下游的海洋初级生产力产生影响，从而影响全球碳循环。
The ocean region along the latitude of 40°S in the South Atlantic, characterized by enhanced primary productivity, forms a transition zone between the nutrient replete but iron depleted Southern Ocean, and the nitrate and iron depleted Subtropical Gyre. Here, we present distributions of nutrient-type dissolved and particulate trace metals (dTMs and pTMs) including cadmium (Cd), nickel (Ni), copper (Cu), and zinc (Zn) in the South Atlantic from the GEOTRACES GA10 cruises. Phytoplankton uptake, riverine and atmospheric inputs shaped dTM and pTM concentrations in surface waters (dCd 27.8 ± 36.0 pmol kg−1, n = 222; dCu 0.732 ± 0.429 nmol kg−1, n = 222; dNi 3.38 ± 0.52 nmol kg−1, n = 219; dZn 0.332 ± 0.398 nmol kg−1, n = 214). Subsurface nutrients and dTMs (dCd 563 ± 184 pmol kg−1, n = 335; dCu 1.819 ± 0.773 nmol kg−1, n = 334; dNi 6.19 ± 1.06 nmol kg−1, n = 330; dZn 3.71 ± 2.10 nmol kg−1, n = 333) were controlled by the mixing of Antarctic origin waters and North Atlantic Deep Waters (NADW) with negligible contributions from local remineralization. Dissolved and particulate TMs in the Argentine Basin showed elevated concentrations towards the seafloor because of benthic inputs. Direct hydrothermal inputs of dTMs and pTMs to deep waters were not observed along the transect. The Cd-Cu-Zn-phosphate stoichiometries of Antarctic origin waters were set by a combination of dynamic physical circulation and preferential uptake of Cd, Cu, and Zn relative to phosphate in surface waters because of a dominance by diatoms in the Southern Ocean. Water mass mixing subsequently produced convoluted dCu-P and dZn-P relationships and apparent linear dCd-P and dNi-P relationships in the South Atlantic. More importantly, endmember characteristics of Antarctic waters and NADW are largely fixed in their formation regions in high latitude oceans. Therefore, the highly dynamic high latitude oceans are key regions that supply nutrients and TMs at specific ratios to low latitude oceans via the thermohaline circulation. Changes to processes in the high latitude oceans may have consequences for marine primary productivity downstream, and hence the global carbon cycle.