What in the World Why is there so much seaweed on our beaches?
Dec 24, 2025
Georgina Rannard, BBC climate and science correspondent, dives into the troubling rise of seaweed blooms around the globe, linking them to climate change and ecological disruptions. Santiago Stebelski, a young entrepreneur from Mexico, shares his journey founding Sargolico, a venture transforming sargassum into sustainable bioplastics. They discuss the harmful effects of seaweed on biodiversity, potential solutions like carbon sequestration, and how technology could help predict future blooms. It's an eye-opening look at innovation meeting environmental challenges.
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Seaweed Blooms Are A Visible Global Phenomenon
- Massive seaweed blooms are global, affecting Europe, the Americas and East Asia.
- Satellites can visualise huge clumps like the Great Atlantic Sargassum Belt from space.
Multiple Pathways Bring New Seaweed Species
- Seaweed arrives from varied sources: native blooms, escaped farmed species, and transport in ship ballast water.
- Invasive species have established after escaping farms or via ballast discharge.
Decaying Seaweed Creates Smell And Health Risks
- Washed-up seaweed decays, smells bad and can release toxins that irritate skin or lungs.
- Decay and chemical release create public-health and nuisance problems on affected beaches.