They support an incredible array of biodiversity and may also be some of the world’s most effective carbon sinks. But vast swathes of seagrass meadows have been lost in the last century, and they continue to vanish at the rate of a football pitch every half hour. Madeleine Finlay makes a trip out of the Guardian office to visit a rewilding project in Hampshire. She speaks to marine biologist Tim Ferrero about the challenges of replanting seagrass meadows and what hope it offers.. Help support our independent journalism at theguardian.com/sciencepod