The Ocean Biome

The ocean holds the largest of Earth’s biomes. It covers 70% of the planet’s surface.

Life in the ocean is diverse. The smallest creatures that call the ocean home are so tiny that they can only be seen with a microscope. The largest creatures are blue whales, which can be as much as 34 meters (110 feet) long. There are many different ways to live in the ocean, too. Some animals travel huge distances through ocean water. Others stay in the same place on the ocean floor their entire lives. Some burrow beneath the sand while others float near the surface.

The ocean is not the same everywhere.  There are many different ecosystems within the ocean depending on conditions such as the water temperature, the amount of sunlight that filters through the water, and the amount of nutrients.

Sunlight breaks through the top layer of ocean water. It can make its way as deep as 200 meters (656 feet). Almost all marine life (about 90%) lives within this top, sunlit layer of the ocean. There, phytoplankton, algae, and plants like seagrass make their own food through the process of photosynthesis and are the start of most marine food chains.

The temperature of ocean water varies depending on its location. Water near the polar regions is colder than water near the equator. Water that is deep in the ocean is colder than water that is near the ocean surface. Many animals and other organisms can only survive at certain temperatures.  Others are able to survive at a range of temperatures and can live in more places in the ocean.

The following links give an overview of four different environments where life flourishes in the ocean. 

  • Life in the Intertidal Zone - Where the ocean meets the land, hardy animals, plants, and algae make their homes between the low tide and high tide levels.
  • Life in the Open Ocean The largest area of the marine ecosystem, the open ocean is home to swimming fish, drifting plankton, and other creatures.
  • Life in the Shallow OceanIn the sunlit parts of the shallow ocean, many animals, plants, and algae thrive on the seafloor as fish zoom above.
  • Life in the Deep OceanThis cold, dark world offers some very unusual extreme environments where many living things have found ways to survive.
Last modified June 1, 2010 by Lisa Gardiner.

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Photosynthesis

Photosynthesis is the name of the process by which autotrophs (self-feeders) convert water, carbon dioxide, and solar energy into sugars and oxygen. It is a complex chemical process by which plants and...more

Life in the Intertidal Zone

The intertidal zone is the area along a coastline that is underwater at high tide and above the water at low tide. Life in the intertidal zone needs to be able to survive extreme conditions - both above...more

Life in the Open Ocean

The open ocean, called the pelagic zone, is the largest area of the marine ecosystem. It reaches from coasts to the middle of the ocean. The living things that survive in the open ocean need to have a...more

Life in the Deep Ocean

The deep ocean is very cold, under high pressure, and always dark because sunlight can not get down that far. Less life can survive in the deep ocean than in other parts of the ocean because of these conditions. ...more

Biomes and Ecosystems

Biomes are large regions of the world with similar plants, animals, and other living things that are adapted to the climate and other conditions. Explore the links below to learn more about different biomes....more

Early Whales Gave Birth on Land

Scientists discovered two fossil whales in 2000 and 2004 in Pakistan. The fossils are a pregnant female and a male of the same species of primitive whale. After much work, scientists have made some exciting...more

Aquifer

An aquifer is the name for a layer of rock which is capable of holding a large amount of water. Some layers are better at holding water than others, for example a layer of sandstone can hold a good deal...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA