New satellite imagery has revealed the Great Atlantic Sargassum Belt has reached one of its largest recorded sizes, stretching nearly 5,000 miles across the Atlantic Ocean.
Rather than a newly discovered geological formation, the belt is a vast accumulation of floating sargassum seaweed extending from the west coast of Africa across the tropical Atlantic to the Caribbean and Gulf of Mexico.
Scientists estimate the belt now contains approximately 37.5 million metric tons of seaweed, making it one of the largest blooms observed since satellite monitoring began.
In the open ocean, sargassum serves an important ecological role by providing habitat for fish, sea turtles, crabs, and countless marine organisms. The floating ecosystem supports biodiversity throughout the Atlantic and serves as a nursery for many species.
However, when large quantities of the seaweed wash ashore, the impacts can be significant. Coastal communities throughout the Caribbean, Gulf Coast, and parts of Florida have experienced beach closures, declining tourism, and environmental concerns as decomposing seaweed produces unpleasant odors and reduces oxygen levels in nearshore waters.
Researchers believe several factors are contributing to the belt’s continued growth, including warmer ocean temperatures, increased nutrient runoff from major river systems such as the Amazon, and changing ocean currents.
The latest satellite imagery underscores how modern Earth observation technology is helping scientists monitor large-scale environmental changes across the globe. Researchers continue to study the long-term causes behind the expanding sargassum belt and what it could mean for marine ecosystems and coastal communities in the years ahead.
Sources:
Diario AS. (2026, June). New images from space reveal a previously unknown structure stretching almost 5,000 miles in the Atlantic Ocean. https://en.as.com/
NASA. (2023). Satellite observations of Atlantic sargassum and ocean ecosystems. NASA Earth Observatory.
