Seaweed - we have been using it for centuries in food and toiletries. It can help to keep toothpaste and ice cream soft, as well as being a tasty snack. It is a billion-dollar industry. But in some parts of the world, supply of the crop has decreased dramatically due to climate change. Now people in Zanzibar are fighting back. They are learning new methods of farming seaweed in deeper, cooler waters. It is boosting the amount of seaweed they can grow and improving their livelihoods as a result. Produced and presented by Celestina Olulode. Additional production by Esther Namuhisa and Nicholaus Mtenga.