Why do worms prefer hydrothermal vents in the Pacific while shrimp preferthose of the Atlantic? Quentin Cooper puts this question to marine biologist Professor Paul Tyler , who has been investigating which of these creatures live in the hydrothermal vents of the Indian Ocean. Cooper also asks whether the undersea volcanic ridges act as a bridge to these species or a barrier and what additional problems are faced when working in deep ocean environments. Producer Fiona Roberts. E-MAIL: material.world@bbc.co.uk