The deep sea

Mariana Trench

By current measurements it reaches almost 11,000 metres below sea level.

💡 Did you know? It is named after the British survey ship HMS Challenger.

1,100 bar

That is more than a thousand times the air pressure at the surface, as if a small car stood on every square centimetre.

💡 Did you know? Every ten metres of water adds roughly one bar.

Trieste

The bathyscaphe was designed by Auguste Piccard; the crew sat in a steel sphere beneath a huge petrol tank that provided buoyancy.

💡 Did you know? It was named after the Italian city of Trieste; the US Navy bought it in 1958.

Jacques Piccard

The Swiss oceanographer was the son of the balloonist Auguste Piccard, who had designed the Trieste.

💡 Did you know? Jacques’s son Bertrand Piccard also became famous, as a balloonist who flew round the world nonstop.

James Cameron

His craft, Deepsea Challenger, was a green vessel that sank upright, with a cabin just over a metre across.

💡 Did you know? For “Titanic” Cameron had already filmed the real wreck at a depth of about 3,800 metres.

Alvin

At the Galápagos Rift they found tube worms, clams and crabs living around the vents without sunlight.

💡 Did you know? Alvin also carried researchers to the wreck of the Titanic in 1986.

Black smokers

Their dark colour comes from metal sulphides that settle out in the cold seawater and make the chimneys grow.

💡 Did you know? Bacteria there draw energy from chemicals rather than light, the basis of entire communities of life.

Bioluminescence

The light comes from a chemical reaction; animals use it to lure, hide or scare.

💡 Did you know? By some estimates three out of four animals of the open deep sea can glow.

Anglerfish

The glow in the bait often comes from bacteria that live inside it.

💡 Did you know? In some species the tiny male bites onto the female and fuses with her for good.

Giant squid

Japanese researchers lured it with bait in front of a camera about 900 metres down off the Ogasawara Islands.

💡 Did you know? Its eyes are as big as dinner plates and among the largest in the animal kingdom.

Dumbo octopus

The two fins on its head look like big ears; it uses them to row slowly over the seabed.

💡 Did you know? It lives several thousand metres down and is one of the deepest-living octopuses of all.

Blobfish

Its saggy look appears only at the surface; in the deep the pressure keeps its jelly-like body in shape.

💡 Did you know? It lives off Australia and New Zealand at depths of about 600 to 1,200 metres.

2,000 metres

A dive can last more than an hour; down there the whales mainly hunt squid.

💡 Did you know? Sucker scars on their skin bear witness to fights with large squid.

Hadal zone

The name goes back to Hades, the god of the underworld in Greek myth.

💡 Did you know? Even down there fish still live: snailfish have been filmed more than 8,000 metres down.

Abyssal zone

It covers a large part of the ocean floor; the water there is only a few degrees above freezing.

💡 Did you know? The word comes from the Greek “abyssos”, bottomless.

Marine snow

It is made of plankton remains, droppings and mucus, and is the main food for many deep-sea animals.

💡 Did you know? A single flake can take weeks to reach the bottom of the deep sea.