From the Caribbean to the Mediterranean, tonnes of seaweed is turning up on beaches in ever bigger quantities. Seaweed blooms — massive, rapid accumulations of seaweed — are smelly and can release toxic gases. They’re also crowding out native plants. So where is all this seaweed coming from and is it down to climate change? BBC climate and science correspondent Georgina Rannard explains what effect this extra seaweed is having on biodiversity.

Lots of countries and scientists are trying to work out what to do with all this seaweed - and even find ways to use it in the fight against climate change. We speak to Santiago Stebelski, who’s 20 and from Mexico. He and his brother have just founded a company called Sargolico, which aims to convert sargassum seaweed into bioplastic.

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Presenter: Hannah Gelbart
Producers: Julia Ross-Roy, William Lee Adams and Adam Chowdhury
Editor: Emily Horler