El Niño disrupts Pacific marine food web and ecosystems

The strengthening of the 2026 El Niño in the equatorial Pacific is causing significant disruptions to the marine food web. Satellite observations from the NASA Earth Observatory indicate a notable decline in surface chlorophyll concentrations in the Central Pacific compared to June 2025 levels. Because chlorophyll is essential for photosynthesis, this decrease suggests a reduction in phytoplankton, which forms the foundation of the ocean's food chain.

Oceanographers note that El Niño can inhibit the upwelling process, where cold, nutrient-rich waters rise from the ocean depths to the surface. As equatorial trade winds weaken, the warm surface layer of the ocean lengthens, potentially blocking nutrient supply. This phenomenon affects a vast area equivalent to approximately one-seventh of the planet, with marine temperature anomalies reaching up to 3°C.

While the most intense meteorological effects are expected in regions near the Pacific—such as Chile, Peru, Central America, California, China, Indonesia, and Australia—the impact on distant regions like Europe and Italy may be delayed by three to six months and is generally less direct.