What is Marine Biomes? | Types, Definition, Structure, Function & Facts

What is Marine Biomes?

There are two main aquatic or aquatic biomes, marine biomes and freshwater biomes. Marine biomes are mainly made up of saltwater oceans. It is the largest biome on planet Earth and covers about 70% of the Earth’s surface. Go here to learn more about the different oceans of the world.

Types of Marine Biomes

Although marine biome is mainly made up of oceans, it can be divided into three categories:

Oceans – These are the five main oceans that cover the world, including the Atlantic, Pacific, Indian, Arctic, and Southern Oceans.

Coral Reefs – Coral reefs are small compared to the oceans, but about 25% of marine species live in coral reefs, making it an important biome. Head here to learn more about the Reef Biome.

Estuaries – An estuary is an area where rivers and streams flow into the sea. This area where freshwater and saltwater meet, creating an ecosystem or biome of its own with interesting and diverse plant and animal life.

Ocean Light Zones

Oceans can be divided into three classes or regions. These layers are called light zones because they are based on the amount of sunlight each zone receives.

Sunlit or Euphotic Zone – This is the top layer of the ocean and receives the most sun. Depths vary, but are about 600 feet deep on average. Sunlight provides energy for marine organisms through photosynthesis. It eats plants as well as small organisms called plankton. Plankton is important in the ocean because it forms the food base for much of the rest of ocean life. As a result, about 90% of marine life lives in sunny areas.

Twilight or Disphotic Zone – Twilight zone or dichroic zone – The twilight zone is the mid-ocean region. It ranges from about 600 feet deep to about 3,000 feet deep depending on the turbidity of the water. There is too little sun for plants to live here. The animals that live here have adapted to life without light. Some of these animals can produce their own light through a chemical reaction called bioluminescence.

Midnight or Aphotic Zone – Midnight Zone or Loss of Light – Below about 3000 is the midnight zone. There’s no light here, it’s completely dark. The water pressure is very high and very cold. Only a few animals have adapted to live in these extreme conditions. They live off microbes that get their energy from cracks in the Earth at the bottom of the ocean. About 90% of the ocean is in this area.

Animals of the Marine Biome

Marine biomes have the highest biodiversity of all biomes. Many animals, such as fish, have gills that allow them to breathe water. Other animals are mammals that need to come to the surface to breathe, but spend most of their lives underwater. Another type of marine animal is a mollusk with a mollusk and no backbone.

Here are some of the animals you’ll find in marine biomes:

Fish –Shark, Swordfish, Tuna, Clownfish, Grouper, Stingray, Flatfish, Eel, Rockfish, Seahorse, Mola Sunfish and Tilapia.

Marine Mammals – Blue whales, seals, walruses, dolphins, manatees, and otters.

Mollusks – Octopus, cuttlefish, clams, conch, squids, oysters, slugs, and snails.

Plants of the Marine Biome

There are thousands of species of plants that live in the ocean. They depend on photosynthesis from the sun for energy. Ocean plants are vitally important to all life on planet Earth. Algae in the ocean absorb carbon dioxide and provide much oxygen to the Earth. Examples of algae include kelp and phytoplankton. Other marine plants are algae, seagrasses and mangroves.

Interesting Facts About the Marine Biome

More than 90% of life on Earth lives in the ocean.

The average ocean depth is 12,400 feet.

About 90% of volcanic activity takes place in the world’s oceans.