Starting in early April, NASA satellites began to detect a patch of brownish, blue-green water lingering off the coasts of New Jersey, Delaware, Maryland, and Virginia. The colors and patterns were most intense in the shallow coastal zone where the waters of Raritan Bay, Delaware Bay, and Chesapeake Bay merged with the Atlantic Ocean—an area known as the Mid-Atlantic Bight.
It’s a part of the ocean that remote sensing scientists typically describe as being “noisy” or “dirty” because rivers often discolor coastal waters with plumes of suspended sediment, water stained with colored dissolved organic matter, and an array of microscopic and aquatic plant life. All of this can mingle with ephemeral phytoplankton blooms, sometimes in mucky waters against a varied backdrop of seagrass, sand flats, and rocky sea bottoms.
This mix creates optical complexity that has long made it harder for scientists to distinguish and categorize phytoplankton blooms in shallow coastal zones compared to the deeper, darker, more uniform waters of the open ocean. Yet with the arrival of missions like PACE (Plankton, Aerosol, Cloud, Ocean Ecosystem), which launched in 2024 and measures more wavelengths of light than previous ocean color missions, scientists are growing increasingly confident in identifying phytoplankton blooms even in optically complex coastal areas.
Multiple NASA satellites—including PACE, Aqua, and Terra—have captured images of colorful water in recent weeks. While some of the color visible in the images may be due to outflows from coastal rivers and sediment churned up by spring storms, “there are likely phytoplankton blooms happening,” said Anna Windle, a research scientist at NASA’s Goddard Space Fli …