The oceans may be an integral part of the planet earth and its ecosystems, but these massive bodies of water are sometimes viewed as worlds within themselves.

Their massive scope and depth have left areas that even leading oceanographers haven’t explored. Likewise, there are plenty of different species of animals, plants, and even microorganisms that live in the planet’s various oceans.

Life began in the oceans, and this has led humanity to maintain great interest in studying these bodies of water and even dividing them up into portions to make the analysis easier.

These sections, also known as zones of the ocean or more simply ocean zones, each have their own depth and biological characteristics. Each of the zones in the ocean also have their own distinct species inhabiting them.

Future dead species and environmental damage can potentially be avoided if humankind takes a greater interest in studying zones of the open ocean and the consequences of ocean pollution in each zone.

The Epipelagic Zone – the Sunlight Zone

This zone goes about 200 meters or just over 650 feet below the ocean’s surface. As the name suggests, the sunlight penetrates this highest zone, providing the means for photosynthesis.

Any list of ocean zones facts will note that plant species like free-floating algae, seaweed, phytoplankton, and many others are common in the sunlight zone. It’s one of the ocean life zones that supports many common sea animals like dolphins, blue whales, sea turtles, jellyfish, and sharks.

Because of the direct exposure to sunlight, this has the highest temperature of all the zones of the ocean.

The Mesopelagic Zone – the Twilight Zone

This zone picks up at the 200 meter/650 foot level beneath the sunlight zone and goes about 1,000 meters or 3,280 feet down.

A lack of sunlight because of the depth makes this a dead zone ocean level in terms of photosynthesis. The lack of light means plants aren’t around at this level, but supported animal species include crabs, squids, swordfish, clams, krill, and several others.

The fish in this zone are usually very mobile, and they have tough bodies with developed muscles and rigid skeletal structures. Their gills are also well developed for proper respiration since they live in one of the deeper ocean life zones.

The Bathypelagic Zone – the Midnight Zone

From roughly 1,000 meters/3,280 feet down to 4,000 meters/13,123 feet exists the midnight zone. With even less sunlight than the twilight zone, this is one of the zones in the ocean with very scarce amounts of nutrients.

Like the zone above it, this is a dead zone ocean area in terms of plant life. However, large whales, sea stars, and various species of squid, octopus, and shark all live in this area. Because of the low level of nutrients in the midnight zone, ocean life living there typically have slim bodies, fragile skin, and a low rate of metabolism.

zones of the ocean

Image via Quora

Only about 5 percent of the food from the twilight zone reaches this midnight zone.

The Abyssopelagic Zone – the Abyssal Zone

Also simply called the abyss, this area goes down from the end of the midnight zone and bottoms out at about 6,000 meters or 19,690 feet.

With a low temperature and a lack of nutrients and oxygen, this zone lives up to its name and makes it hard for species to survive. However, species of squids, sea stars, and sea spiders can feed off the scraps of nutrients that come down from the levels above.

The abyss is also home to the bizarre tube worm – discovered in the 1970s, the creature has no mouth, intestines, or excretory system.

This is one of the zones of the open ocean that remains largely unexplored. It isn’t by choice – in addition to the near-freezing temperature, the high pressure of the abyssal zone makes it a treacherous location.

The Hadalpelagic Zone – the Trenches

Also called the Hadal zone, the trenches extend to the deepest parts of the ocean which are deeper than 6,000 meters or 19,686 feet down.

Trenches are actually cavities on the deepest parts of the ocean. The Marina Trench is off the coast of Japan and is over 10,000 meters/36,000 feet down.

The only species able to survive at this depth are those that have adapted to the frigid temperatures, and those able to use chemicals from the Earth’s interior rather than sunlight. These include various types of sea worms, plankton, and one-celled organisms.

Ocean life zones can provide a lot of insight about aquatic species, and each of the zones of the ocean offers its own knowledge. The consequences of ocean pollution can affect all these areas, showing how the zones in the ocean are distinct yet interdependent – just like the ocean’s relationship with the Earth.

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