The abyssal zone is the part of the ocean's water column from about 4,000 m down to about 6,000 m, where no sunlight reaches. Most of the deep seabed, including the abyssal plains, lies within it.
Key takeaways
- The abyssal zone runs from about 4,000 m to about 6,000 m, below the bathypelagic zone and above the hadal zone.
- It is completely dark, and the water is cold and under great pressure.
- The ocean's mean depth in our grid is 4,085 m, so a large part of the seabed sits at or near this zone.
- Some authors use slightly different depth limits, so check which one a source uses.
How the abyssal zone works
The ocean is divided into depth zones, one below another. The abyssal zone, also called the abyssopelagic zone, runs from about 4,000 m down to just above the seabed, where the seabed is shallower than 6,000 m [1]. Beyond 6,000 m, in the trenches, the water belongs to the hadal zone.
"Abyss" comes from a Greek word for "bottomless". In this zone it is complete darkness [1], so any light is made by animals themselves. The water is cold and under great pressure, and the animals that live there depend on food sinking from above.
This is a zone of water, defined by depth, and not a type of ground. But the ground matters, because the seabed across much of the ocean basins sits within it. Abyssal plains usually lie between about 3,000 and 6,000 m [2], so they overlap the abyssal zone and part of the zone above it. That is why the two terms are often used together.
Boundaries differ between sources. Some sources put the top of the abyssal zone higher, near 3,000 m, and the Wikipedia page used here gives about 4,000 m [1]. The exact edges are a convention, since the water changes gradually. What does not change is the order of the zones, and the fact that the abyssal zone is the one that covers the broad floor of the deep ocean.
Our map does not draw ocean zones. It only colours the seabed by depth, so you can read the zone from the colour ramp or from the depth card when you tap.
An example from our data
The depth of the abyssal zone can be tested with the drain the oceans slider. At the 4,000 m step, the page reports 53.2% of the sea remaining. At the 6,000 m step, that falls to 1%. That is a crude way of saying how much of the seabed lies between 4,000 and 6,000 m: most of what is left at the first step is gone at the second.
This is the simple bathtub model, which lowers the sea everywhere by the same amount on today's seabed, so it is a depth exercise and not a prediction.
For a sense of scale, the five oceans average 4,085 m by area, and the Pacific Ocean has a median depth of 4,422 m. Both are close to the top of the abyssal zone.
The thing people get wrong
People often use "abyss" for the deepest places in the ocean, such as the Mariana Trench. But the deepest trenches are not in the abyssal zone. They are in the hadal zone, below it. The abyssal zone is the broad floor of the ocean, not the extreme holes cut into it. The deepest point on our map, 10,927 m, is well below the abyssal zone's lower edge.
Frequently asked questions
How deep is the abyssal zone?
About 4,000 m to about 6,000 m, though some sources start it at 3,000 m.
Is there light in the abyssal zone?
No. It is in complete darkness.
Sources
- Pelagic zone, Wikipedia.
- Abyssal plain, Wikipedia.
- Every figure from our own map is worked out from the datasets on the data sources page (checked against GEBCO_2026 grid).