6000 m and beyond

Hadal zone

The ocean trenches. The least explored realm on the planet, reaching over 11,000 m at the Mariana Trench.

Light: Total darkness

Temperature: 1–4°C

Pressure: 600 to over 1100 atm

Ocean trenches reaching this depth

Harmless

Pseudoliparis swirei

The deepest-living fish ever confirmed, discovered in 2014 and formally described in 2017 in the Mariana Trench, at nearly 8,000 m below the surface.

🌊 6198–8076 m

⚡ The deepest-living fish ever confirmed, down to about 8,000 m
⚡ Its cells are protected from being crushed by a molecule (TMAO) that stabilises its proteins under extreme pressure

Harmless

Hirondellea gigas

A scavenging crustacean that thrives in the total darkness of the ocean's deepest point, able to digest even sunken wood thanks to a unique enzyme.

🌊 6800–10935 m

⚡ Lives down to nearly 10,935 m, one of the deepest-living animals known on Earth
⚡ Produces an enzyme (cellulase) able to digest sunken wood, an exceptional ability for a crustacean

Harmless

Grimpoteuthis sp.

The cephalopod observed at the greatest depths ever recorded: it owes its name to its two ear-shaped fins reminiscent of the Disney elephant.

🌊 1000–7000 m

⚡ The cephalopod observed at the greatest depths ever recorded, down to about 7,000 m
⚡ Swims by flapping two ear-shaped fins, a technique unique among octopuses