ISRO’s Oceansat-3 satellite has detected a decline in marine productivity across parts of the equatorial Pacific Ocean as El Niño conditions developed in 2026. Scientists at ISRO’s National Remote Sensing Centre analysed satellite observations of chlorophyll-a, a key indicator of phytoplankton abundance, along with ocean-surface winds for April–June during 2023–2026.
Compared with June 2024 and June 2025, satellite observations from June 2026 showed a notable reduction in surface chlorophyll-a. ISRO linked the change to weakening and reversal of the usual easterly trade winds. This disrupts equatorial upwelling, reducing the supply of cold, nutrient-rich water to the sunlit surface and thereby limiting phytoplankton growth.
The observations demonstrate how satellite data can reveal the close connection between ocean circulation, climate variability and marine ecosystems. ISRO says that if the developing El Niño intensifies, the low-chlorophyll region could become more pronounced. Further observations will help track the evolving phenomenon
