March 25, 2021 - Arabian Sea Phytoplankton Bloom and Sunglint

bloom in Arabian Sea

Swirls of pale blue filled the Arabian Sea off the coast of Oman in late March 2021. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of the scene on March 24.

The color marks a large bloom of phytoplankton, which are microscopic plant-like organisms that live in these waters in smaller numbers year-round. When conditions are right—enough sunlight, nutrients, and favorable water temperatures—these tiny organisms can reproduce explosively, creating huge blooms that are easily seen from space.

While a large blue bloom appears off the coast of Oman, all the water seen in this image carries color created by phytoplankton, other than the silver gleam in the lower left. This gleam is caused by sunglint, an optical phenomenon that occurs when sunlight reflects off the surface of water at the same angle that a satellite sensor views it. The result is a mirror-like specular reflection of sunlight off the water and back at the satellite sensor or astronaut.

Image Facts
Satellite: Aqua
Date Acquired: 3/23/2021
Resolutions: 1km (987.1 KB), 500m (2.7 MB), 250m (5.7 MB)
Bands Used: 1,4,3
Image Credit: MODIS Land Rapid Response Team, NASA GSFC