NASA satellite data reveals El Niño’s impact on Pacific marine ecosystems
New observations from the PACE satellite confirm that weakened trade winds and suppressed upwelling have drastically reduced chlorophyll concentrations in the central equatorial Pacific, with tangible effects on Peru’s anchovy industry.
Satellite measurements from NASA’s PACE mission indicate that the El Niño event, which officially arrived in June 2026, has significantly reduced chlorophyll concentrations in the central equatorial Pacific. The weakening of easterly trade winds and suppressed upwelling of nutrient-rich water have decreased phytoplankton abundance, disrupting the marine food web. In Peru, this has led to profound declines in anchovy catches, resulting in repeated fishery suspensions by the Ministry of Production and increased sightings of pelicans in urban areas. NOAA’s Climate Prediction Center expects the event to strengthen through the end of 2026, with a 97 percent probability of lasting into early Northern Hemisphere spring 2027.
The PACE satellite, launched in February 2024, is providing the first complete monitoring of this El Niño cycle. Data from the Ocean Color Instrument shows that chlorophyll-a concentrations, an indicator of phytoplankton abundance, are substantially lower in mid-2026 compared to neutral conditions in June 2025. The most noticeable difference appears in the central Pacific, around the equator due north of New Zealand.
Matthew Kehrli and Graham Trolley, oceanographers at NASA’s Goddard Space Flight Center, note that these changes are expected as trade winds weaken and the warm surface layer of the ocean extends deeper. They anticipate that differences in the central Pacific will become more pronounced as the event progresses, potentially manifesting as a broadening region of reduced surface chlorophyll-a concentration.
Reductions in phytoplankton have ripple effects through the marine food web, impacting zooplankton, fish, seabirds, and marine mammals. In Peru, anchovy fisheries have seen profound declines in catch, driven by warmer surface waters and reduced upwelling. The Ministry of Production has repeatedly suspended the fishery to safeguard the country's main fishing resource, while pelicans have been seen venturing into Peruvian ports and urban areas in search of food.
Despite the disruptions, a post-El Niño “chlorophyll rebound” can occur, fuelled by higher iron concentrations in ocean currents and dust from drier land areas. Scientists hope to use PACE data to gauge the responses of specific phytoplankton communities to El Niño variability, with the mission’s hyperspectral measurements offering new insights into these ecological shifts.
