Iron is an essential nutrient that regulates productivity in ~30% of the ocean. Compared with deep (>2000 meter) hydrothermal activity at mid-ocean ridges that provide iron to the ocean’s interior, shallow (<500 meter) hydrothermal fluids are likely to influence the surface’s ecosystem. However, their effect is unknown. In this work, we show that fluids emitted along the Tonga volcanic arc (South Pacific) have a substantial impact on iron concentrations in the photic layer through vertical diffusion. This enrichment stimulates biological activity, resulting in an extensive patch of chlorophyll (360,000 square kilometers). Diazotroph activity is two to eight times higher and carbon export fluxes are two to three times higher in iron-enriched waters than in adjacent unfertilized waters. Such findings reveal a previously undescribed mechanism of natural iron fertilization in the ocean that fuels regional hotspot sinks for atmospheric CO 2 .

中文翻译：

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浅层热液源的天然铁施肥助长了海洋中的重氮营养菌大量繁殖

铁是一种必需的营养素，可调节约 30% 的海洋的生产力。与为海洋内部提供铁的中洋脊的深层（>2000 米）热液活动相比，浅层（<500 米）热液可能会影响表面的生态系统。然而，它们的作用是未知的。在这项工作中，我们表明沿汤加火山弧（南太平洋）喷出的流体通过垂直扩散对透光层中的铁浓度产生重大影响。这种富集刺激了生物活动，产生了大片叶绿素（360,000 平方公里）。富铁水域的固氮菌活性和碳输出通量比相邻的未施肥水域高两到三倍。2个.