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 stays around 4 °C (39 °F) and has very little light, as sunlight cannot reach these deep waters. The pressure here is very high, ranging from 100 to 400 atmospheres due to the depth.

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

Biogeochemistry

The bathypelagic zone relies on organic matter from the layers above it, such as the epipelagic and mesopelagic zones, to support life. This organic material, often called marine snow, sinks down and provides food and nutrients for deep-sea creatures. Hydrothermal vents also play a role by releasing heat and chemicals like sulfide and methane, which some organisms use to survive.

One important process in this zone is the breakdown of carbon. Most carbon starts in the upper ocean and moves deeper, a process called the biological pump. This carbon helps remove carbon from the atmosphere and store it in the ocean. Scientists are studying how quickly this carbon breaks down in the deep sea to better understand 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 organic material that falls from the upper layers of the ocean. This material provides food for tiny organisms, fish, and other sea creatures that live in the deep.

Many different types of animals live in the bathypelagic zone, including special kinds of fish like anglerfish and gulper eels. Some of these fish have adaptations like bioluminescence, which lets them produce their own light. Because food is scarce in the deep ocean, these animals have slow metabolisms to save energy. Occasionally, when large amounts of organic matter, like a dead whale, fall into the zone, it creates a short time of increased activity for the animals there.

Research and exploration

This part of the ocean, called the bathypelagic zone, is not well understood because it is hard to reach. It is very deep, far from land, and the water pressure there is extremely strong. Scientists have only recently begun studying places far from the coast and at great depths, thanks to new technology and better ways to work together.

Important discoveries in this zone began in 1977 when scientists found communities of animals that lived not on sunlight, but on chemical 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 mysterious deep-sea areas.

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. Some places, like the Arctic, might see more carbon moving down into the ocean, but overall, less carbon will end up stored deep down.