Marine biologist, diver and author Dr Helen Scales takes Dr Karl deep beneath the waves to share her passion for life in the ocean. Helen talks about her new book 'Spirals in Time' on the secret life of shells. Hear about 'clacking' oysters, the legend of the Golden Fleece (sea silk) and a creature resembling a pinecone crossbred with a slug. There's mathematics in the spirals of shells, slave trading in the history of the cowrie shell and just imagine a Harry Potter golden snitch of the sea… it's real and has an incredibly important role to play in ocean life.