Background Info

This set of marine community illustrations can be used as visual aids during formal or informal instruction while teaching about the marine realm. There are three versions of each illustration:


  • unlabeled illustration
  • titled, unlabeled illustration
  • titled, labeled illustration


The three different versions were created in order to provide materials that best suit the needs of any educational situation.


Different areas of the ocean can be classified as different types of marine ecosystems. An ecosystem is defined as "a community and the interactions of living and nonliving things in an area." Marine ecosystems have distinct organisms and characteristics that result from the unique combination of physical factors that create them. Marine ecosystems include: the abyssal plain (areas like deep sea coral, whale falls, and brine pools), polar regions such as the Antarctic and Arctic, coral reefs, the deep sea (such as the community found in the abyssal water column), hydrothermal vents, kelp forests, mangroves, the open ocean, rocky shores, salt marshes and mudflats, and sandy shores.

The hydrosphere connects all freshwater and saltwater systems. Salinity, or high salt content, and global circulation make marine ecosystems different from other aquatic ecosystems. Other physical factors that determine the distribution of marine ecosystems are geology, temperature, tides, light availability, and geography.


Some marine ecosystems are very productive. Near-shore regions, including estuaries, salt marshes, and mangrove forests, teem with life. Others, like the abyssal plain at the bottom of the ocean, contain pockets of life that are spread far apart from one another. Some marine ecosystems, like the deep sea, are in constant darkness where photosynthesis cannot occur. Other ecosystems, like rocky shores, go through extreme changes in temperature, light availability, oxygen levels, and other factors on a daily basis. The organisms that inhabit various marine ecosystems are as diverse as the ecosystems themselves. They must be highly adapted to the physical conditions of the ecosystem in which they live. For example, organisms that live in the deep sea have adapted to the darkness by creating their own light source—photophores are cells on their bodies that light up to attract prey or potential mates. Many parts of the ocean remain unexplored and much still remains to be learned about marine ecosystems.

Fast Facts

  • Polar bears paws are up to 12 inches long. They act like snowshoes for polar bears in the Arctic, preventing them from sinking into the ice and snow.
  • Angler fish that live in the deep sea ecosystem can eat prey that is twice its size because of its large mouth and huge stomach.
  • Octopuses can squirt ink out of their backsides, which forms a smoke-like cloud that will help them to escape from a predator.
  • A squabble is the term for a group of seagulls.
  • Sperm whales can dive more than 1.6 kilometers (one mile) below the surface of the water.
  • Male seahorses give birth, rather than female seahorses.
  • Giant tube worms, located in the hydrothermal vent ecosystem at 2,499 meters (8,200 feet) below the surface, have long, white bodies and no eyes, mouth, or stomach. The worms soak up chemicals from the hydrothermal vent to feed to the bacteria living inside them. In return, the bacteria make food for the tube worm.
  • Green sea turtles, unlike other sea turtles, go ashore to warm themselves in the sun.


Term Part of Speech Definition Encyclopedic Entry

abyssal plain


extensive, featureless region of the deep ocean floor.



process by which some microbes turn carbon dioxide and water into carbohydrates using energy obtained from inorganic chemical reactions.



group of organisms or a social group interacting in a specific region under similar environmental conditions.

coral reef


rocky ocean features made up of millions of coral skeletons.



community and interactions of living and nonliving things in an area.

Encyclopedic Entry: ecosystem



mouth of a river where the river's current meets the sea's tide.

Encyclopedic Entry: estuary



all the Earth's water in the ground, on the surface, and in the air.

Encyclopedic Entry: hydrosphere

kelp forest


underwater habitat filled with tall seaweeds known as kelp.



type of tree or shrub with long, thick roots that grows in salty water.

marine ecosystem


community of living and nonliving things in the ocean.



coastal wetland formed as rivers or tides deposit sediment.



large body of salt water that covers most of the Earth.

Encyclopedic Entry: ocean



process by which plants turn water, sunlight, and carbon dioxide into water, oxygen, and simple sugars.




salt marsh


coastal wetland that is flooded with seawater, often by tides.


Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.


Julie Brown, National Geographic Society


Doris Dialogu

Page Producer

Samantha Zuhlke, National Geographic Society

User Permissions

For information on user permissions, please read our Terms of Service.

If you have questions about licensing content on this page, please contact for more information and to obtain a license.

If you have questions about how to cite anything on our website in your project or classroom presentation, please visit our FAQ page.


Some media assets (videos, photos, audio recordings and PDFs) can be downloaded and used outside the National Geographic website according to the Terms of Service. If a media asset is downloadable, a download button appears in the lower right hand corner (download) of the media viewer. If no button appears, you cannot download or save the media.


Text on this page is printable and can be used according to our Terms of Service.


Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.