Animals that live in the Ocean
The Earth is often called ‘The Blue Planet’ because 70% of its surface is covered in water. There are five oceans:
- The Atlantic Ocean
- The Pacific Ocean
- The Indian Ocean
- The Arctic Ocean
- The Southern Ocean
Each of the world’s oceans has different characteristics and supports a great diversity of aquatic life.
There are also distinct layers within each ocean. The sun shines on the sea like on land, but it can’t reach the darkest depths. Therefore, the shallows differ significantly from the sea bed; each layer is home to very different creatures.
There are five ocean layers:
- The Sunlight Zone: The sunlight layer is the first layer from 0 to 200metres deep.
- The Twilight Zone: Second up is the Twilight Zone from 200 to 1000 meters deep.
- The Midnight Zone: The midnight zone extends from1000 from 4000 meters deep.
- The Lower Midnight Zone: This zone reaches from4000 to 6000 meters deep.
- The Trenches: At the deepest and darkest point of the ocean, the trenches begin from 6000 meters deep and beyond.
The Sunlight Zone
The sunlight zone is where most sea animals live. True to its name, it gets the most sunlight and tends to be a warm 12-20 degrees Celsius on average due to its proximity to the sun.
What plants and animals live in the sunlight zone?
Seaweed, plankton, and flowering plants are common in the sunlight zone because there’s enough sunlight to perform photosynthesis.
The sunlight zone is also home to many animal residents, such as turtles, sting rays, seals, sea lions, dolphins, jellyfish, coral, and other fish species. In addition, most animals and plants discovered in the sea exist in the sunlight zone because the sunlight and temperature here allow them to survive.
The Twilight Zone
The temperature in the Twilight zone is generally between 4 and 13 degrees Celsius.
What plants and animals live in the Twilight Zone?
The Twilight Zone is home to whales, octopuses, swords, hatchet fish, and shrimp. Because of the lack of sunlight in this region, no plants can grow at depths below the sunlight zone.
However, sponges can grow here. Contrary to popular belief, sponges are not plants. They are, in fact, animals with dense skeletons but no brains or other organs. They don’t move and grow from a fixed spot, which means they are ‘sessile’ animals.
The Midnight Zone
The midnight zone is sometimes known as ‘the deep.’ The temperature typically sits at around 4 degrees C. Sunlight does not reach this layer at all, so the only light at this level is produced by bioluminescent animals: animals that have their light, like the infamous anglerfish.
What other animals live here?
Other than the anglerfish, the only animals you’ll find here are giant whales, echinoids, squid, and blobfish. But, of course, you might stumble across a few shipwrecks too– the wreck of the Titanic was discovered in the midnight zone at a depth of 3800m.
The Lower Midnight Zone
The lower midnight zone is very dark and cold – the temperature is around freezing.
Do any animals live in the lower midnight zone?
Despite the extreme conditions, this is one of the largest environments on earth, and some species live here in this dark, expansive part of the sea. Sea spiders, medusas, basket stars, and sea pigs have all been discovered living in the Lower Midnight Zone.
The Trenches
The Trenches are extremely cold and dark. It’s completely pitch black, and almost impossible to see most of the creatures that live there. ‘Challenger Deep’ in the Mariana Trench is the deepest known trench in any ocean.
Can anything survive in the trenches of the ocean?
We cannot see most of the animals that live in the trenches. So it poses the question, what else lives down there that we haven’t discovered yet?
Some fish do live in this layer. For example, the Rattail and liparid fish can survive in the deepest parts of the deep sea. Amphipods (shrimp-like creatures) live there and wait for food scraps to drop from the layers above. Decapods, ten-footed crustaceans, eat these amphipods.
