Epipelagic Zone (Sunlight Zone) 

The initial zone is the epipelagic zone better known as the sunlight zone. This zone is the zone closest to the surface and the zone that provides the most light, hence the name sunlight zone. This zone is the smallest zone in the ocean but also provides a lot of life which is due to photosynthesis. Photosynthesis provides plant life which in turn provides life for smaller organisms that the larger organisms such as sharks or whales feed on. The epipelagic zone is where humans are able to fish due to the shallower waters and abundance of fish. This zone is known for the world's most well-known sea creatures, such as sharks, dolphins, whales, and other notable animals. 

Mesopelagic Zone (Twilight Zone) 

 The next zone is the mesopelagic zone or the twilight zone. The mesopelagic zone is the area of the ocean between 650 to 3,300 feet and contains much less sunlight when compared to the epipelagic zone. You’ll also find that the majority of life is in the mesopelagic zone. Hardly any light penetrates these depths, yet life persists. In this region, squid, krill, jellies, and fish abound in profusion. Around 10 billion tons of fish, or nearly 90% of all fish in the world, are found in the mesopelagic. ( Hall & Osborn, 2022). This zone is still largely unexplored, but we do know that it contains some of the smallest and largest species on the planet, and due to light being so few and far between, some species in this zone produce their own light through bioluminescence. This shows that species adapt and evolve to fit their environment. 

Bathypelagic Zone (Midnight Zone) Abyssopelagic Zone (The Abyss) & Hadal Zone (Trenches)

There is no light in the bathypelagic zone or the ‘midnight zone’. The zone is claimed to be between 3,300 and 13,100 feet and has very intense pressure at those depths. Although there is no light, there is still life. Unfortunately, little is known about the creatures that inhabit this zone and that is due to poor funding and shows the need for more exploration. Below the bathypelagic zone is the abyssopelagic zone. This zone goes down to the sea floor but does not include deeper trenches. This zone is similar to the bathypelagic zone as it has even higher pressures and cooler temperatures. Similar species that live in the bathypelagic zone live here as well. The final zone of the ocean is the hadalpelagic zone. This zone is the absolute deepest part of our oceans, which are unfortunately barely explored, and little to nothing is truly known about the creatures that inhabit this zone. This zone includes the ocean floor and even deeper trenches such as the Mariana Trench. Regardless of the extreme depths and high pressures of this zone, plastic has been found and recorded in this zone, which goes to show how extreme of a problem pollution is. 

Abyssal Plain, Abyssal Hill & Seamount

After descending the continental slope you will then enter the abyssal plain. Abyssal plains cover 70 percent of our ocean floor. This makes the abyssal plain a major feature. At this point, light does not pass through the water which in turn makes this entire habitat dark. Despite the name abyssal plain, it is not flat throughout the whole floor. An abyssal plain may consist of many seamounts and abyssal hills.  Seamounts' are large mountains underwater emerging from the sea floor.  Majority of these seamounts' used to be active volcanoes, which is very similar to a lot of mountains on land. Within these depths of an abyssal plain, seamounts and abyssal hills are where life is most active and present. Abyssal hills are small hills that lower the depth of an abyssal plain. 

Ocean Trenches

Ocean trenches are formed through tectonic plates converging and being pushed beneath one another. This causes steep depressions in the ocean which as a result forms the deepest parts of our oceans. When these tectonic plates converge and one plate ends up beneath the other this is called subduction which is how these steep trenches are made. Deep sea trenches are what make up the 'hadal zone' and these ocean trench depths can range from 24,000 to 36,000 feet. At these depths, water pressure is immense and completely unsurvivable for human beings. During an expedition into the Mariana Trench, which is the deepest ocean trench on our planet, we discovered that the pressure was more than 16,000 PSI at the bottom. This compared to the average PSI of our atmosphere which is 14.7 PSI is nothing short of remarkable. It goes to show that we still know so little about our trenches, but they play such an important role on our planet as a lot of our earth's seismic activity comes from our trenches. 

Hydrothermal Vents

Hydro thermic vents are found most frequently around areas where there are known volcanic activity in our oceans. The discovery of hydrothermal vents in 1977 had a major effect on our outlook on life and how it worked. During that time, we thought life was dependent on light and photosynthesis, and after seeing how life truly thrived around hydrothermal vents our understanding changed. Hydrothermal vents shoot out high-temperature water that contains chemicals and minerals. These chemicals convert to energy which is a process called Chemosynthesis. This process is strikingly similar to how light converts to energy. The minerals that are emitted over time solidify and form chimney-like structures which is the appearance of a hydrothermal vent.  These vents emit water at temperatures up to 750 °F. The water pressure at these depths prevents the water that is emitted through the earth's crust from boiling.  Hydrothermal vents are such a significant discovery as they gave us new knowledge and understanding of how life works. This should only drive researchers and scientists to continue to explore to find such mesmerizing phenomena as hydrothermal vents.