CLIMATE · VERIFIED DEVELOPMENT
2026 El Niño Triggers Decline in Pacific Phytoplankton, Threatening Food Web
WHY IT MATTERS
The observed phytoplankton loss indicates that fisheries managers should intensify catch monitoring to anticipate and respond to potential reductions in fish stocks.
What happened
Satellite data from NASA’s Earth Observatory show a sharp fall in surface chlorophyll across the Central Pacific as the 2026 El Niño intensifies, compared with neutral conditions in June 2025. The pigment drop signals a reduction in phytoplankton, the base of the ocean’s food chain.
Oceanographers explain that weaker easterly trade winds during El Niño slow upwelling, keeping nutrient‑rich cold water below the surface and extending the warm layer. As the event progresses, chlorophyll concentrations are expected to fall further over a wider area.
The resulting nutrient shortfall will limit food for zooplankton, fish, seabirds and marine mammals, echoing past declines in Peru’s anchovy fisheries during earlier El Niño events.
PRIMARY SOURCES
El Niño is disrupting the Pacific’s marine food web from the bottom up
Mongabay · Shreya Dasgupta · Discovery and factual synthesis only; publisher copyright terms apply