Bathypelagic zone

The bathypelagic zone or bathyal zone is a part of the open ocean that lies between 1,000 and 4,000 meters below the ocean surface. It is found between the mesopelagic zone above and the abyssopelagic zone below. Because no sunlight reaches this deep area, it is often called the midnight zone.

Since there is no sunlight, photosynthesis cannot happen here. This means there is no primary production, so there are no phytoplankton or aquatic plants to form the base of food chains like in shallower waters.

Even though the bathypelagic zone makes up a huge part of the ocean by volume, we still know relatively little about it. Exploring such deep waters is very difficult, so much of this mysterious part of the ocean remains full of unknowns.

Physical characteristics

The bathypelagic zone is very cold, staying around 4 °C (39 °F). There is very little light here because sunlight cannot reach these deep waters. The pressure is very high, ranging from 100 to 400 atmospheres because of the depth.

This zone starts at the edge of the continental shelf and goes up to the top of the abyssal zone. It includes areas along continental slopes, seamounts, and mid-ocean ridges. These features create special homes for deep-sea animals. Hydrothermal vents in some parts of this zone support unique ecosystems that use chemicals instead of sunlight for energy.

Biogeochemistry

The bathypelagic zone gets food from layers above it, like the epipelagic and mesopelagic zones. This food, called marine snow, sinks down and feeds deep-sea animals. Hydrothermal vents help too, by giving out heat and chemicals like sulfide and methane, which some creatures need to live.

One big job of this zone is breaking down carbon. Carbon mostly starts near the surface and moves down, in a process called the biological pump. This helps take carbon from the air and keep it in the ocean. Scientists study how fast this carbon breaks down to learn more about the global carbon cycle.

Ecology

The bathypelagic zone, also called the midnight zone, is a deep part of the ocean with no sunlight. Because there is no light, plants and algae cannot grow here. Instead, this zone relies on bits of food that fall from the upper layers of the ocean. This food helps tiny organisms, fish, and other sea creatures survive.

Many different animals live in the bathypelagic zone, including special kinds of fish like anglerfish and gulper eels. Some of these fish can make their own light, called bioluminescence. Because food is hard to find in the deep ocean, these animals use very little energy to stay alive. Sometimes, when big pieces of food, like a dead whale, fall into the zone, the animals become more active for a short time.

Research and exploration

The bathypelagic zone is a deep part of the ocean that is hard to study. It is very far from land and the water pressure is very strong. Scientists have only recently started to explore these deep areas because of new technology and better ways to work together.

In 1977, scientists made an important discovery. They found animals that lived not on sunlight, but on energy from hot water coming out of the ocean floor. Today, scientists use special underwater robots called remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs) to explore these deep and mysterious places.

Climate change

See also: Effects of climate change on oceans

The oceans help protect us from climate change by soaking up carbon dioxide and heat. But as the air gets warmer and has more carbon dioxide, the oceans can't do this as well. This can change the water and make it harder for animals that live deep in the ocean.

The deep ocean, called the bathypelagic zone, helps store carbon for a very long time. This is important because it keeps some of the carbon out of the air. But with more carbon in the air, this storage might get weaker.