June 24, 2021 — Travel thousands of metres below the surface of the ocean, and you reach the seabed. Pitch black and quiet, it is largely unexplored, untouched, unknown.
What is known is extraordinary. The landscape at the bottom of the sea is as varied as the earth surface: 4,000m (13,000ft) down, abyssal plains stretch for miles like deserts; there are trenches large enough to swallow the Earth’s largest mountains; venting chimneys rise in towers like underwater cities; seamounts climb thousands of metres. Hot thermal vents – believed by some to be the places where all life on Earth started – gush highly acidic water at temperatures of up to 400C, drawing in an array of creatures.
So little is known about what happens this far under the sea that in the 25 years following the discovery of the hydrothermal vents, an average of two new vent species are discovered every month. They include the yeti crab, a ghostly white crustacean with silky-blonde bristles on its claws that give it a resemblance to the Abominable snowman. Others discovered in the last 20 years include the beaked whale and the Greenland shark, which dives to around 1,200m and has a lifespan of close to 400 years, making it one of the world’s longest-living organisms.
“Every time you go down into the deep, you see something incredible and often new,” says Diva Amon, a deep sea biologist and fellow at the Natural History Museum in London who has undertaken 15 deep sea expeditions.
“There’s a bone-eating worm called Osedax, which lives on the bones of dead whales in the deep … Another special one was … an anemone whose tentacles were 8ft long.”