Oceanic Zones

Four major oceanic zones

Oceanic zones form the largest ecosystem on Earth

There are four major oceanic zones where plants and animals live in the ocean. The four major zones are intertidal zone, neritic zone, open ocean zone and benthic zone. These zones contain the largest ecosystem on Earth.

Abundant life is found on the summit of a seamount near Guam, NOAA

Abundant life on the summit of a seamount near Guam, NOAA

Major zones in the oceans

Intertidal zone

The intertidal zone is the area of the seafloor between high tide and low tide. It bridges the gap between land and water. Tide pools, estuaries, mangrove swamps and rocky coastal areas are all part of the intertidal zone.

Neritic zone

The water above the continental shelf is the neritic zone. Underwater forest of kelp and grassy meadows of sea grass are home to tiny fish, green turtles, sea cows, seahorses and tiny shrimp. Coral reefs have thousands of animals and plants that live in the waters of the neritic zone.

Open ocean zone

The open ocean zone lies beyond the continental slope and contains 65% of the water in the oceans. This zone is divided further into three subzones. The sunlit zone is where photosynthesis takes place. Plankton and jellyfish are drifters that inhabit this zone. Most animals living in the open ocean live in the sunlit zone.

Twilight zone

Below the sunlit zone is the twilight zone where some light penetrates the ocean to a depth of 3000 feet. Viper fish, firefly squid, and the chambered nautilus live in this zone. The midnight zone extends from a depth of 3000 feet to the seafloor. Animals found in this zone include the giant squid, deep sea hatchetfish and bioluminescent jellyfish.

Benthic zone

The benthic zone includes the entire seafloor. About 200,000 species of plants and animals live here. They live on the continental shelf and continental slope. Hydrothermal vents discovered in 1977 are also teeming with life. These plants and animals doe not need sunlight to exist.

More Ocean Links

What Causes Tsunamis Today we know that tsunamis are naturally generated waves. Find out how and why they form.

Mid Atlantic Ridge The Mid-Atlantic Ridge is a mountain range that runs down the center of the Atlantic Ocean through Iceland. 

Ocean Trenches  Ocean trenches are found all around the Pacific Ring of Fire. Find out how and why they develop.

Sea mount  There are more than 60,000 sea mounts located in the world's oceans.

Oceanic Zones  Find out about the four major zones where plants and animals live in the ocean. 

Ocean Facts  Discover what causes tsunamis, where ocean trenches are located and how the Mid-Atlantic Ridge was discovered.

Home Page  The Science Site contains information on our planet, volcanoes, science projects, earthquakes and much more.


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