Super El Niño Transforms Ocean Colors, NASA Satellite Data Reveals
Warmer waters associated with the climate phenomenon are causing plankton die-offs, leading to a shift from green to blue hues in the equatorial Pacific.
NASA satellite imagery indicates that the current Super El Niño is significantly altering the color of the world's oceans, turning waters in the equatorial Pacific measurably bluer. This change is attributed to a decline in photosynthesizing plankton, which are crucial to the ocean's typical emerald green appearance.
Plankton, which can range in color from brown to teal, typically give ocean waters a vibrant green hue when abundant. However, El Niño disrupts ocean currents that bring cold, nutrient-rich water to the surface. Without these essential nutrients, the plankton in the equatorial Pacific are starving, resulting in a deep blue coloration of the water.
El Niño is part of the El Niño Southern Oscillation (ENSO), a natural climate cycle that occurs every two to seven years, alternating between warm El Niño and cool La Niña phases. The current El Niño phase is characterized by hot waters gathering in the equatorial Pacific, raising average temperatures and influencing global weather patterns.
Scientists suggest that the current El Niño could be one of the strongest on record. Predictions indicate an 83% chance that it will be the strongest since records began in 1950. As of October, sea surface temperatures in the eastern Pacific were observed to be 1.7°C (3°F) above the long-term average, with potential for further increases.
The recent launch of NASA's PACE (Plankton, Aerosol, Cloud, Ocean Ecosystem) satellite in 2024 has provided unprecedented views of this unfolding event. The PACE satellite's Ocean Colour instrument measures ocean color in hyperspectral detail, capturing wavelengths across visible, ultraviolet, and infrared spectrums.
During El Niño events, the trade winds that typically push warm water westward weaken or reverse. This reduction in wind strength diminishes the upwelling of nutrient-rich deep ocean water. The subsequent decline in algae, or phytoplankton, leads to the observed bluer ocean tones, as documented by PACE.
This decline in phytoplankton can have cascading effects throughout the marine ecosystem, forcing other marine life to seek new feeding grounds.
NASA scientists first detected early signs of a major El Niño year in January through sea level measurements. Kelvin Waves, slow-moving pulses of water that transport heat across the Pacific, were observed building near Micronesia. These waves warm the air above them, altering atmospheric pressure and weakening the trade winds, thereby initiating the El Niño chain reaction.
By early April, these Kelvin Waves reached the eastern Pacific, contributing to the rise in sea surface temperatures. The warming waters also cause sea levels to expand and rise. In El Niño's critical region, sea levels have risen by as much as 1.3 feet (40cm) near South America and California, while areas like Indonesia and Australia have seen sea levels drop by up to eight inches (20cm).
