HADAL

An institute for the parts of Earth the sun has never reached.

Below the light there is still a place.
Descend.

You are in the

Sunlight zone

Twilight zone

Midnight zone

Abyssal zone

Hadal zone

Photosynthesis happens here, down to about 200 metres. Everything bright and familiar about the ocean lives in this thin layer.

From 200 to 1,000 metres the blue fades to nothing. Animals here make their own light, mostly to hide.

To 4,000 metres: no sunlight at all, water near freezing, and food that arrives as a slow fall of dead plankton.

Down to 6,000 metres, the seafloor is a plain of soft mud. Life is sparse, slow and astonishingly well adapted.

Below 6,000 metres, only the trenches. Named for Hades, and as close to another planet as we can drive to.

Pressure
1 atm
Temperature
24 °C
Light
100 %

Put Evereston the bottom.

Cross-section of an ocean trench: water descending in a narrow V-shaped cut to a pink marker at the deepest point.
0 mSurface
8,849 mSummit of Everest, if it stood here
10,935 mChallenger Deep, Mariana Trench

Its summit would still sit more than two kilometres under water.

Four trenches.
One question each.

Planned dives for the coming season. Depths are the deepest known point of each trench.

10,935m

Mariana Trench

Western Pacific. Does the deepest water on Earth carry its own food web, or only what falls from above?

10,047m

Kermadec Trench

South Pacific. How quickly do animals recolonise after a landslide on a trench wall?

8,376m

Puerto Rico Trench

Atlantic. The deepest point in the Atlantic is also one of the least visited. What lives there?

7,290m

Java Trench

Indian Ocean. Where does the plastic that sinks end up, and who is eating it?

Specimens
from the dark

A glowing teal jellyfish with long trailing tentacles.
AtollaCrown jelly. Flashes a blue alarm when attacked, calling bigger predators to eat its attacker.
An anglerfish with a glowing amber lure above its jaws.
MelanocetusBlack seadevil. The lure is lit by bacteria that live inside it.
A chain of pink bell shaped animals strung together.
SiphonophoraNot one animal but a colony. Some stretch longer than a blue whale.
A translucent shrimp-like amphipod with a glowing amber eye.
HirondelleaA hadal amphipod. Digests wood that sinks to the bottom of the trenches.
A cluster of tall white tube worms topped with pink plumes.
RiftiaGiant tube worm. Has no mouth; feeds on bacteria that eat chemicals from vents.

Then we comeback up.

Everything on this page was measured, photographed and sampled in a place that has no day. We bring it up so that the surface can argue about it in daylight.

  • ≈1,100atmospheres of pressure at Challenger Deep
  • 1–4 °Cwater temperature at the bottom
  • Nonesunlight reaches below 1,000 m

What the dark keeps

Dive notes arrive twice a year, when a trench is dived or a species is named. Nothing else.