A vast realm of cold temperatures, intense pressure and near total darkness, the deep sea is largely unexplored and unknown to humans. Yet billions of creatures live in this mysterious world, many relying on bizarre adaptations that allow them to survive in extreme conditions. Some regularly rise up into sunlit waters, but others never emerge from the blackest depths. Though seemingly remote, the deep sea actually contains most of the habitable space on Earth.

IN THIS EXHIBIT: Zones of the Deep
The "deep sea" here refers to two main zones, the mesopelagic and bathypelagic: vast voids where billions of creatures live in dim light or total darkness. Though the animals depicted here are Western Atlantic, the deep sea looks much the same at any given depth anywhere in the world. In the ocean, the most significant differences are found by moving up or down.

0 to 200 meters:
The sunlit or epipelagic zone is a thin layer where most ocean plants (phytoplanktons) grow.

200 to 1000 meters:
In the twilight or mesopelagic zone, also called midwater, a small amount of sunlight penetrates.

Below 1,000 meters:
The bathypelagic zone is in total darkness. The only light here comes from the animals themselves.

Sea Floor:
At the bottom is the benthic zone, where fallen nutrients on the sea floor create a distinct ecosystem.