By estimating surface nitrate concentrations and new production directly from satellite observations, we reveal a pronounced east–west gradient in ocean productivity. This gradient is shaped by external physical forcing, including wind-driven mixing, winter convective overturning, and major climate events such as El Niño. Together, these processes regulate the delivery of nutrients and iron to surface waters, alter light availability and temperature, and ultimately control phytoplankton growth and oceanic CO₂ uptake.

Our results demonstrate that climate-driven variability strongly influences carbon export from the surface ocean, with cascading implications for the North Pacific’s role in the global carbon cycle. By integrating shipboard observationswith satellite remote sensing, this study provides a comprehensive framework for understanding how physical climate processes translate into biological responses at basin scales.