Professor Heather Koldewey wants to protect our oceans from over-fishing and plastic pollution. An academic who is not content to sit back and let the science speak for itself, she wants to turn science into action and has found conservation allies in some unexpected places. Working with a carpet manufacturer, she created Net-Works, a business that turns old fishing nets into high-end carpet tiles and she has collaborated with Selfridges department store to give marine conservation a make-over. A research career that began studying the genetics of brown trout in Welsh rivers took her to the Philippines to save seahorses and a job running the aquarium at London Zoo. In 2018, she was made a National Geographic Fellow. Heather tells Jim Al-Khalili why, despite all the challenges to marine life, she remains an ‘ocean optimist’ and how she learned to drop her ‘scientific seriousness’. Producer: Anna Buckley