# Pacific Ocean phytoplankton decline during El Niño

> Live situation record from CLSTR: https://clstr.news/situations/pacific-ocean-phytoplankton-decline-during-el-nio
> Updated: 2026-10-23T15:18:01.000Z. Sources: 7. Developments: 2.

Satellite imagery from NASA indicates that the equatorial Pacific Ocean is transitioning from its typical greenish hue to a bright blue color. This visual change is attributed to a significant reduction in phytoplankton populations caused by the 2026 El Niño phenomenon.

Experts explain that warming surface waters and weakened trade winds have disrupted the upwelling processes that normally bring nutrient-rich cold water to the surface. Without these nutrients, phytoplankton levels have dropped. Scientists warn this biological shift could cause cascading effects throughout the marine food web—impacting fish, birds, and marine mammals—while also reducing the ocean’s capacity to absorb atmospheric carbon dioxide.

Some experts suggest there is an ‘83% possibility’ that this specific El Niño event could become one of the strongest in recorded history, with potential consequences lasting through 2027.

## Timeline

### 2026-10-23: NASA satellites detect Pacific Ocean turning blue due to El Niño

NASA satellites show the equatorial Pacific Ocean turning blue as El Niño reduces phytoplankton levels by disrupting nutrient-rich upwelling, threatening marine food webs.

5 sources. https://clstr.news/cluster/nasa-satellites-detect-pacific-ocean-turning-blue-due-to-el-nio

### 2026-10-21: Pacific Ocean turns blue due to declining phytoplankton during El Niño

NASA satellite images reveal the Pacific Ocean is turning blue as El Niño reduces phytoplankton levels, threatening marine food chains and carbon absorption.

2 sources. https://clstr.news/cluster/pacific-ocean-turns-blue-due-to-declining-phytoplankton-during-el-nio

---
Cite as: Pacific Ocean phytoplankton decline during El Niño. CLSTR, https://clstr.news/situations/pacific-ocean-phytoplankton-decline-during-el-nio