Aerosol sizes are highly associated with the solubilities and the deposition fluxes of aerosol Fe in the surface ocean since the sizes may reflect the sources and decide the deposition velocities. However, systematic studies for the association of the solubilities and fluxes have been limited. In this study, five size-fractions of dry aerosols were collected monthly for a year at two islets in the East China Sea, where large amounts of both fine anthropogenic and coarse lithogenic aerosols deposit. Both pure water and buffer leached methodologies were applied to determine the two operationally defined soluble Fe fractions, instantly dissolved Fe (DFe) and supposedly Fe-ligand complexed labile Fe (LFe), respectively. We found that the solubilities of DFe varied up to 4 orders of magnitude with the size spectrum and exhibited a highly linear correlation with non-sea-salt sulfur, indicating that the solubilities of DFe were closely associated with the acidity. Finer aerosols (PM 3) accounted for 92% of total DFe but coarser aerosols (>PM 3) contributed 73% of the difference between LFe and DFe (LFe-DFe). The increasing trend of the difference with increasing sizes indicates that the residence time of coarse aerosol particles and their interaction with Fe-ligands are critical factors deciding the total fluxes of LFe in the ocean. Considering the deposition velocities of each size of aerosols, the averaged fluxes of aerosol Fe of the fine and coarse aerosols were 1.6 and 5.3 nmol m⁻² d⁻¹ for DFe; and 2.5 and 56 nmol m⁻² d⁻¹ for LFe in the East China Sea, respectively. Attributed to the relatively low deposition velocities of fine aerosols, we found that either single or two averaged deposition velocities (fine/coarse) that were used in most of the previous studies would significantly overestimate soluble Fe fluxes in regions where the contribution of fine anthropogenic aerosols is dominant, such as the open ocean. In conclusion, this study demonstrates that aerosol sizes are essential and powerful parameters to accurately estimate the solubility and the fluxes of aerosol soluble Fe.

气溶胶尺寸与表层海洋中气溶胶铁的溶解度和沉积通量高度相关，因为尺寸可以反映来源并决定沉积速度。然而，关于溶解度和通量的关联的系统研究受到限制。在这项研究中，在东海的两个小岛上，在一年内每月收集五个大小的干气溶胶，那里有大量的细人为气溶胶和粗大的岩石气溶胶沉积。纯水和缓冲液浸出方法均用于确定两种操作上定义的可溶性铁组分，即速溶铁 (DFe) 和假定的铁配体络合不稳定铁 (LFe)。我们发现DFe的溶解度随尺寸谱变化高达4个数量级，并且与非海盐硫呈高度线性相关，表明DFe的溶解度与酸度密切相关。较细的气溶胶 (PM 3) 占总 DFe 的 92%，但较粗的气溶胶 (>PM 3) 占 LFe 和 DFe (LFe-DFe) 差异的 73%。差异随粒径的增大而增大的趋势表明，粗颗粒气溶胶颗粒的停留时间及其与铁配体的相互作用是决定海洋中 LFe 总通量的关键因素。考虑到各种尺寸气溶胶的沉积速度，细气溶胶和粗气溶胶的平均气溶胶Fe通量分别为1.6和5.3 nmol m 表明 DFe 的溶解度与酸度密切相关。较细的气溶胶 (PM 3) 占总 DFe 的 92%，但较粗的气溶胶 (>PM 3) 占 LFe 和 DFe (LFe-DFe) 差异的 73%。差异随粒径的增大而增大的趋势表明，粗颗粒气溶胶颗粒的停留时间及其与铁配体的相互作用是决定海洋中 LFe 总通量的关键因素。考虑到各种尺寸气溶胶的沉积速度，细气溶胶和粗气溶胶的平均气溶胶Fe通量分别为1.6和5.3 nmol m 表明 DFe 的溶解度与酸度密切相关。较细的气溶胶 (PM 3) 占总 DFe 的 92%，但较粗的气溶胶 (>PM 3) 占 LFe 和 DFe (LFe-DFe) 差异的 73%。差异随尺寸增大而增大的趋势表明，粗颗粒气溶胶颗粒的停留时间及其与铁配体的相互作用是决定海洋中 LFe 总通量的关键因素。考虑到各种尺寸气溶胶的沉积速度，细气溶胶和粗气溶胶的平均气溶胶Fe通量分别为1.6和5.3 nmol m 差异随尺寸增大而增大的趋势表明，粗颗粒气溶胶颗粒的停留时间及其与铁配体的相互作用是决定海洋中 LFe 总通量的关键因素。考虑到各种尺寸气溶胶的沉积速度，细气溶胶和粗气溶胶的平均气溶胶Fe通量分别为1.6和5.3 nmol m 差异随粒径的增大而增大的趋势表明，粗颗粒气溶胶颗粒的停留时间及其与铁配体的相互作用是决定海洋中 LFe 总通量的关键因素。考虑到各种尺寸气溶胶的沉积速度，细气溶胶和粗气溶胶的平均气溶胶Fe通量分别为1.6和5.3 nmol m^-2 d ^-1用于 DFe；东海 LFe 的含量分别为2.5 和 56 nmol m ^-2 d ^{-1 。}由于细小气溶胶的沉积速度相对较低，我们发现以前大多数研究中使用的单个或两个平均沉积速度（细/粗）都会显着高估人为细小气溶胶贡献区域的可溶性铁通量占主导地位，例如开阔的海洋。总之，本研究表明，气溶胶尺寸是准确估计气溶胶可溶性铁的溶解度和通量的重要且强大的参数。