New dissolved aluminum (dAl) data from the 2017 GEOTRACES process study GApr08 along 22°N in the subtropical North Atlantic are presented. They show an east to west increase in dAl concentration in the surface waters. Simulation of these data with a 1D advection-dust deposition revealed that, (a) advection and dust dissolution are equally important dAl sources, (b) scavenging plays a minor role compared to advection in dAl removal, and (c) in addition to dust dissolution, another dAl source is required at the westernmost stations to fully explain our observations. We attribute this additional source to the dissolution of erosion products delivered to the western subtropical North Atlantic by the Lesser Antilles. For waters deeper than ∼200–300 m, an optimum multi-parameter analysis allowed to separate the component of the dAl signal derived from water mass transport from its biogeochemical component. This revealed, (a) a major role played by water mass transport, (b) a net dAl removal between 200 and 800 m, attributed to scavenging at the subtropical North Atlantic scale, and (c) internal dAl inputs between 800 m and the seafloor, attributed to reversible scavenging. While the dAl oceanic distribution is usually considered to be dominated by the atmospheric dust input and removal by particle scavenging, this study highlights the important role played by advection, and the need to explicitly take this into account in order to quantitatively reveal the impact of external sources and dissolved-particulate interactions on the Al cycle in the North Atlantic Ocean.

中文翻译：

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水体传输和溶解粒子相互作用对北大西洋亚热带铝循环的重要性

介绍了来自 2017 年 GEOTRACES 过程研究 GApr08 沿 22°N 在亚热带北大西洋的新溶解铝 (dAl) 数据。它们显示地表水中 dAl 浓度从东到西增加。用一维平流-粉尘沉积对这些数据进行模拟表明，(a) 平流和粉尘溶解是同等重要的 dAl 源，(b) 与平流相比，清除在 dAl 去除中的作用较小，(c) 除了粉尘溶解，在最西端的站点需要另一个 dAl 源来充分解释我们的观察结果。我们将这一额外来源归因于小安的列斯群岛输送到西亚热带北大西洋的侵蚀产物的溶解。对于深度超过 200-300 m 的水域，最佳的多参数分析允许将来自水质量传输的 dAl 信号的成分与其生物地球化学成分分开。这表明，(a) 水团运输发挥的主要作用，(b) 200 到 800 m 之间的净 dAl 去除，归因于北大西洋亚热带范围内的清除，以及 (c) 800 m 和 800 m 之间的内部 dAl 输入海底，归因于可逆的清除。虽然 dAl 海洋分布通常​​被认为是由大气灰尘输入和通过颗粒清除去除的主导，但本研究强调了平流所起的重要作用，并且需要明确考虑到这一点，以便定量揭示外部环境的影响。北大西洋铝循环的来源和溶解颗粒相互作用。