Abstract. Bioavailable Fe is an essential nutrient for phytoplankton that allows organisms to flourish and drawdown atmospheric CO₂ affecting global climatic condition. In marine locales remote from the continents extraterrestrial-dust provides an important source of Fe and thus moderates primary productivity. Here we provide constraints on partitioning of extraterrestrial Fe between seawater and sediments from observations of dissolution and alteration cosmic spherules recovered from the deepsea sediments and Antarctica. Of the ~ 3000–6000 t/a extraterrestrial dust that reaches Earth surface, ~ 2–5 % material survives in marine sediments whilst the remainder is liberated into seawater. Both processes contributes ~ (3–10) × 10⁻⁸ molFe m⁻² yr⁻¹. Also, Fe contribution due to evaporation of survived particle is estimated to be ~ 10 % of Fe contribution to meteoric smoke. Changes in extraterrestrial-dust flux vary not only the amount of Fe by up to three orders of magnitude, but also the partitioning of Fe between surface and abyssal waters depending on entry velocity and evaporation.

中文翻译：

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地外灰尘是海洋生产力中生物可利用铁的来源

摘要。可生物利用的铁是浮游植物的必需营养素，可使生物体繁盛并吸收影响全球气候条件的大气CO ₂。在远离大陆的海洋地区，地外粉尘提供了重要的铁来源，因此降低了初级生产力。在这里，我们根据从深海沉积物和南极洲回收的溶解和蚀变宇宙小球的观测结果，提供了对地外铁在海水和沉积物之间分配的限制。在到达地球表面的约3000–6000吨/天的外星尘埃中，约有2-3％的物质保留在海洋沉积物中，而其余部分则被释放到海水中。这两个过程的贡献约为（3-10）×10 ^-8  molFe m ^-2  yr^-1。同样，由于残留颗粒的蒸发，Fe的贡献估计约为Fe对流星烟雾的贡献的10％。地外尘埃通量的变化不仅使铁含量变化多达三个数量级，而且还取决于进入速度和蒸发量，铁在地表水和深海中的分配。