The Blue Planet: Seas of Life Coral Seas

In the depths of the Atlantic Ocean, where hydrothermal vents spew forth scorching hot chemicals and toxic gases, lies a secret to all life on earth. It's here that seawater and rock react under extreme pressures and temperatures, producing complex hydrocarbons - the building blocks of life itself.

As we delve into this alien world, we discover new species every time we visit these strange new worlds. Shrimps hover near billowing clouds of volcanic chemicals, so hot they could melt lead. Hair-covered crabs feed on gushing plumes of toxic hydrogen sulphide. And in these volcanic hotspots, extraordinary micro-worlds blossom into life, completely divorced from the energy of the sun.

Tectonic plates rip apart or collide in mighty clashes, creating a world where only three human beings have ever set foot. Yet, despite the inhospitable environment, there is still life to be found in these deep sea trenches. From here, we journey on down to the deepest place on earth - the Mariana Trench - almost 11 kilometres from the surface.

The sheer weight of water above creates almost unendurable pressures, making it one of the most extreme environments on the planet. Yet, even eight kilometres down, where the basic chemistry of life was once thought impossible, we find strange species swimming through the darkness. Fish that walk instead of swim, worms that feed exclusively on bones, and shrimps that spend almost their entire lives imprisoned with their mate in a cage of crystal sponge are just a few examples of the incredible adaptability of life.

In the desert wastes of the abyss, a whale carcass generates a frenzy as slow-moving sharks as big as great whites fight for what may be their first meal in a year. We encounter savage hordes of Humboldt squid hunting lanternfish in the depths and coral gardens flourishing in absolute darkness, with more species of coral to be found in the deep than on shallow tropical reefs.

This episode takes us on an epic journey into the unknown, a realm that feels almost like science fiction. Scientists already think that there is more life in the deep than anywhere else on Earth. We have barely begun to explore it, and yet it is the largest living space on the planet - the blue planet's seas of life coral seas.

Blue planet seas of life coral seas