In summer 2025, waters in the Gulf of Maine popped with vivid swirls of blue and green.
In summer 2025, waters in the Gulf of Maine popped with vivid swirls of blue and green. The cause was a massive bloom of phytoplankton—microscopic plant-like organisms that often float near the ocean surface. Scientists say it was one of the largest blooms of its kind to show up in the gulf’s waters in recent years.
The OCI (Ocean Color Instrument) on NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite captured this image of the colorful waters on June 21, 2025. According to Catherine Mitchell, a satellite oceanographer at Bigelow Laboratory for Ocean Sciences, the bloom contained coccolithophores. Armored with plates of highly reflective calcium carbonate, this type of phytoplankton makes water appear milky blue.
The tiny organisms, along with other types of phytoplankton, including diatoms that bloom here in spring, lie at the base of the marine food web. Their presence—or absence—in Gulf of Maine waters can affect the entire ecosystem, from finfish to shellfish, and the region’s fisheries that depend on them.
Read more at NASA Earth Observatory
Image: NASA Earth Observatory image by Wanmei Liang, using PACE data from NASA EOSDIS LANCE and GIBS/Worldview.
