China’s ambitious underwater mapping operation takes us on a voyage into the depths of ocean and map science.

We look at what a network of underwater microphones can tell us about underwater geography, noisy ships, and whale conversations, and how it took nearly 300 researchers working together to map 140 000 neurons in a fruit fly’s brain.

Then, we are joined by biogeochemist and author Karen Lloyd, who tells us about the long-lived microbes living deep in the crust below the sea floor, how they survive for 100 000 years, and what their mysterious existence tells us about life and evolution.

And forget sunken treasures – we will talk about the valuable, potato-sized mineral nodules that grow on the sea floor, and the pros, cons and current legality of mining them. Plus – how dolphins can help us track down abandoned undersea explosives.

All that and even more unexpected elements.

Presenter: Marnie Chesterton, with Katie Silver and Tristan Ahtone