NASA's PACE satellite recorded substantially lower chlorophyll across much of the central equatorial Pacific in June 2026 than under neutral conditions a year earlier, as El Niño reorganized winds and ocean circulation.
Chlorophyll is the light-absorbing pigment used by phytoplankton. Satellite ocean-color measurements use it as a proxy for the abundance and distribution of these microscopic organisms, but the measurement is not a direct organism count.
During El Niño, weaker easterly trade winds allow the warm surface layer to deepen across the central and eastern Pacific. That change suppresses the normal rise of cold, nutrient-rich water from below.
With fewer nutrients reaching sunlit surface waters, phytoplankton growth and chlorophyll concentrations can decline. NASA's June maps show the clearest reduction through the central equatorial Pacific and extending north of New Zealand.
The comparison pairs June 2025, when tropical Pacific conditions were neutral, with June 2026 as El Niño strengthened. Differences between two monthly views do not by themselves determine the size of ecological effects at every location.
PACE provides near-daily hyperspectral observations across many wavelengths. NASA says the 2026–27 event will be the mission's first opportunity to observe a complete El Niño cycle from onset through decline.
NASA cited a NOAA Climate Prediction Center forecast giving El Niño a 97% chance of persisting through early Northern Hemisphere spring 2027. Seasonal probabilities are updated as observations change.
Lower chlorophyll can affect marine food webs, but the NASA analysis does not document a current fisheries collapse or quantify catch losses. Biological responses depend on species, location, timing and conditions beyond surface ocean color.
Future PACE observations will show whether chlorophyll patterns persist, migrate or recover as winds and upwelling evolve. The satellite record is an observational tool, not a deterministic forecast for any individual fishery.