Marine net primary production (NPP) is remarkably high given the typical vertical separation of 50–150 m between the depth zones of light and nutrient sufficiency, respectively. Here we present evidence that many autotrophs bridge this gap through downward and upward migration, thereby facilitating biological nutrient pumping and high rates of oceanic NPP. Our model suggests that phytoplankton vertical migration (PVM) fuels up to 40% (>28 tg yr⁻¹ N) of new production and directly contributes 25% of total oceanic NPP (herein estimated at 56 PgC yr⁻¹). Confidence in these estimates is supported by good reproduction of seasonal, vertical and geographic variations in NPP. In contrast to common predictions, a sensitivity study of the PVM model indicates higher NPP under global warming when enhanced stratification reduces physical nutrient transport into the surface ocean. Our findings suggest that PVM is a key mechanism driving marine biogeochemistry and therefore requires consideration in global carbon budgets.

海洋净初级生产（NPP）非常高，因为光和养分充足深度区域之间典型的垂直间隔分别为 50-150 m。在这里，我们提供的证据表明，许多自养生物通过向下和向上迁移弥合了这一差距，从而促进了生物营养物质的泵送和海洋 NPP 的高速率。我们的模型表明，浮游植物垂直迁移 (PVM) 为高达 40% (>28 tg yr ^-1 N) 的新产量提供燃料，并直接贡献了 25% 的海洋 NPP 总量（这里估计为 56 PgC yr ^-1）。NPP 季节性、垂直和地理变化的良好再现支持了对这些估计的信心。与常见的预测相反，PVM 模型的敏感性研究表明，当增强的分层减少物理养分向表层海洋的运输时，全球变暖下的 NPP 较高。我们的研究结果表明，PVM 是推动海洋生物地球化学的关键机制，因此需要在全球碳预算中加以考虑。