Episode 1: A Portal to Another Realm

The deep sea is one of our last frontiers. For most of human history, it was a vast, dark, and unknown realm that invoked awe and terror. Now, one thing we do know is that it is critically important and central to the future of life on this planet.

In The Dark Frontier, marine microbiologist and deep-sea explorer Jeffrey Marlow reveals how life can thrive in even the most remote, unforgiving landscapes. Professor Marlow takes us on a series of deep-sea dives in the world’s most scientifically-advanced submersible:
“Gelatinous creatures whir by the window. We overtake a sinking gob of seaweed, a micro-universe unto itself. By a depth of two hundred metres beneath the waves, virtually no light remains. Beneath this boundary lies the deep sea – more than 95% of the earth’s habitable volume. I am struck by the realisation that the ocean we’ve been looking at all these years from shores and ships is in fact a portal to another realm – one that may well be the largest, most diverse, most consequential habitat on earth.”

Jeffrey Marlow’s research focuses on understanding the microbes that inhabit the rocks and sediments of the seafloor. In his lab in Boston, he works with a team of scientists to discover how these communities of microbes perform feats of metabolic ingenuity that shape the global carbon cycle and push the boundaries of life’s limits in extreme environments.

In this first episode, he takes us on a deep dive into the Caribbean Sea and sees the ocean’s “biological pump” in action – a process that removes carbon from the air and the surface ocean and stores it in the deep sea, far from the atmosphere, where it could contribute to global warming.

Reader: Adam Sims
Abridged and produced by Elizabeth Burke
Executive producer: Sara Davies
Sound design: Jon Calver
A Loftus Media production for BBC Radio 4