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Record Sargassum Blooms Threaten Coasts and Economies

11/21/2025

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Summary

Story summary

A belt of Sargassum seaweed spanning 8,800 kilometers drifts across the Atlantic at a record 38 million tons.
First noted in 2011, the phenomenon links to nutrient-rich upwelling and nitrogen runoff.
Researchers from the Max Planck Institute identified cyanobacteria on the algae that boost growth via nitrogen fixation.
The blooms threaten coastal ecosystems and block sunlight.
The blooms release harmful gases and impact tourism and local economies.

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Story summary

A belt of Sargassum seaweed spanning 8,800 kilometers drifts across the Atlantic at a record 38 million tons.
First noted in 2011, the phenomenon links to nutrient-rich upwelling and nitrogen runoff.
Researchers from the Max Planck Institute identified cyanobacteria on the algae that boost growth via nitrogen fixation.
The blooms threaten coastal ecosystems and block sunlight.
The blooms release harmful gases and impact tourism and local economies.