10 Types of Marine Ecosystems

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Introduction to Marine Ecosystems

Mark Webster Wwwphoteccouk / Oxford Scientific / Getty Images
Coral head with fish. Mark Webster Wwwphoteccouk / Oxford Scientific / Getty Images

An ecosystem is made up of the living organisms, the habitat they live in, non-living structures and how all of those relate to and influence each other. A marine ecosystem is one that occurs in or near salt water, which means that marine ecosystems can be found from a sandy beach to the deepest parts of the ocean. An example of a marine ecosystem is coral reef with its associated marine life, such as fish and sea turtles, plus the rocks and sand in the area.

Ecosystems may vary in size, but all the parts of the ecosystem depend upon each other - so that if one part of the ecosystem is removed, it effects everything else.

The ocean covers 71% of the planet, so marine ecosystems make up most of the Earth.

This slide show contains an overview of major marine ecosystems, with types of habitat and examples of marine life that live in each. 

02
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Rocky Shore Ecosystem

Sea Stars at Low Tide / Doug Steakley / Lonely Planet Images / Getty Images
Sea stars in a tide pool, Garrapata State Park, California, United States, North America, Big Sur. Doug Steakley / Lonely Planet Images / Getty Images

Along a rocky shore, you may find rock cliffs, small and large boulders, small and large rocks, and tide pools - puddles of water that can contain a surprising array of marine life. You'll also find the intertidal zone - the area between low and high tide. 

Challenges of the Rocky Shore

Rocky shores can be extreme places for marine animals and plants to live. There may be pounding waves, lots of wind action, and the rising and falling of the tides, which may affect water availability, temperature and salinity. 

At low tide, marine animals have an increased threat of predation.

Marine Life of the Rocky Shore

Specific types of marine life vary with location, but in general, some types of marine life you'll find at the rocky shore include:

  • Marine Algae
  • Lichens
  • Birds
  • Invertebrates such as crabs, lobsters, sea stars, urchins, mussels, barnacles, snails, limpets, sea squirts (tunicates) and sea anemones.
  • Fish
  • Seals and sea lions

Explore the Rocky Shore

Want to explore the rocky shore? Here are 10 Tide Pooling Tips.

03
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Sandy Beach Ecosystem

Gulls and Crab on the Beach / Alex Potemkin / E+ / Getty Images
Gulls and Crab on the Beach. Alex Potemkin / E+ / Getty Images

Sandy beaches may seem lifeless compared to other ecosystems - at least for marine life. Most sandy beaches have plenty of human life! However, they have a surprising amount of diversity. 

Similar to the rocky shore, animals in a sandy beach ecosystem need to adapt to the constantly-changing environment. They need to deal with tides, wave action and water currents, which all may sweep marine animals off the beach, and also move sand and rocks to different locations.  Sand generally is pushed onto the beach during summer months, and pulled off the beach in the winter months, making the beach more gravelly and rocky.

Marine life in a sandy beach ecosystem may burrow in the sand or need to move quickly out of reach of the waves.

Within a sandy beach ecosystem, you'll also find the intertidal zone - the area between low and high tide. Although the landscape isn't as dramatic as that of the rocky shore, you may still find tide pools left behind when the ocean recedes at low tide.  

Marine Life on the Sandy Beach

Occasional marine life include:

  • Sea turtles, who may haul up on the beach to nest
  • Pinnipeds such as seals and sea lions, who may rest on the beach

Regular types of marine life include:

  • Algae
  • Plankton
  • Invertebrates such as amphipods, isopods, sand dollars, crabs, clams, worms, snails, flies and plankton.
  • Fish, in shallow waters along the beach. These include rays, skatessharks, and flounder.

  • Birds, such as plovers, sanderlings, willets, godwits, herons, gulls, terns, whimbrels, ruddy turnstones and curlews. 
04
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Mangrove Ecosystem

Mangroves, Indonesia / Borut Furlan / WaterFrame / Getty Images
Aerial Roots, Mangroves, Alor, Lesser Sunda Islands, Indo-Pacific, Indonesia. Borut Furlan / WaterFrame / Getty Images

Mangroves are areas composed of salt-tolerant plant species.These are generally in warmer areas between the latitudes of 32 degrees north and 38 degrees south. Mangrove trees have roots that dangle into the water, providing shelter for a variety of marine life, and important nursery areas for young marine animals. 

Marine Species Found in Mangroves

Species that may be found in mangrove ecosystems include:

  • Algae
  • Birds
  • Invertebrates such as crabs, shrimp, oysters, tunicates, sponges, snails and insects
  • Fish
  • Dolphins
  • Manatees
  • Reptiles such as sea turtles, land turtles, alligators, crocodiles, caimans, snakes, and lizards
05
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Salt Marsh Ecosystem

Salt Marsh, Cape Cod / Walter Bibikow / Photolibrary / Getty Images
View of the Fort Hill Marsh, Eastham, Cape Cod, Massachusetts. Walter Bibikow / Photolibrary / Getty Images

Salt marshes provide a buffer between the ocean and the mainland. These areas are flooded at high tide, and are composed of salt-tolerant plants and animals.

Salt marshes are important in many ways: they provide habitat for marine life, birds and migratory birds, are important nursery areas for fish and invertebrates, and protect the rest of the coastline by buffering wave action and absorbing water during high tides and storms.

Marine Species Found in a Salt Marsh

Examples of salt marsh marine life:

  • Algae
  • Plankton
  • Birds
  • Fish
  • Occasionally marine mammals such as dolphins and seals. 
06
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Coral Reef Ecosystem

Coral with Variety of Marine Life / Georgette Douwma / The Image Bank / Getty Images
Coral reef scenery with Hawksbill turtle (Eretmochelys imbricata) swimming past soft corals (Dendronephthya sp), and Pygmy sweepers (Parapriacanthus guentheri). Egypt, Red Sea. Georgette Douwma / The Image Bank / Getty Images

Healthy coral reef ecosystems are filled with an amazing amount of diversity, from hard and soft corals to invertebrates of many sizes, to even large animals such as sharks and dolphins. 

The reef-builders are the hard (stony) corals. The basic part of a reef is the skeleton of the coral, which is made of limestone (calcium carbonate). This supports tiny organisms called polyps. Eventually, polyps die, leaving the skeleton behind.

Marine Species Found on Coral Reefs

  • Invertebrates may include: hundreds of species of coral, plus sponges, crabs, shrimp, lobsters, anemones, worms, bryozoans, sea stars, urchins, nudibranchs, octopuses, squid and snails.
  • Vertebrates may include a wide variety of fish, plus sea turtles and marine mammals such as seals and dolphins. 
07
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Kelp Forest

Harbor Seal in Kelp Forest / Douglas Klug / Moment / Getty Images
Harbor Seal in Kelp Forest. Douglas Klug / Moment / Getty Images

Kelp forests are very productive ecosystems. The most dominant feature in a kelp forest is - you guessed it - kelp.  Kelp forests are found in cooler waters that are between 42 and 72 degrees Fahrenheit. They can be found in water depths from about 6 to 90 feet. The kelp provides food and shelter for a variety of organism.

Marine Life in a Kelp Forest

  • Birds, including seabirds such as gulls and terns, and shorebirds such as egrets, herons and cormorants.
  • Invertebrates such as crabs, sea stars, worms, anemones, snails and jellyfish.

  • Fish - including sardines, garibaldi, rockfish, seabass, barracuda, halibut, halfmoon, jack mackerel and sharks (e.g., horn shark and leopard shark).
  • Marine mammals - including sea otters, sea lions, seals and whales.
08
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Polar Ecosystem

School of Saithe fish underwater, Arctic Ocean, Norway / Jukka Rapo / Folio Images / Getty Images
School of Saithe fish underwater, Arctic Ocean, Norway. Jukka Rapo / Folio Images / Getty Images

Polar ecosystems are extremely cold areas at the Earth's poles. These areas have both cold temperatures, and fluctuations in the availability of sunlight - at some times in polar regions, the sun doesn't rise at all. 

Marine Life in Polar Ecosystems

  • Algae
  • Plankton
  • Invertebrates - one of the most important invertebrates in polar waters is krill
  • Birds - penguins are well-known for their ice-loving ways, but they live in the Antarctic, not the Arctic.
  • Mammals - Polar bears are another cold-weather species - but they live in the Arctic, not the Antarctic. Other marine mammals in polar regions include a variety of whale species, plus pinnipeds such as seals, sea lions and walruses
09
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Deep Sea Ecosystem

Deep Sea Coral / NOAA Photo Library
NOAA Photo from Operation Deep Slope 2007 of a A stunning white deep sea coral in the Gulf of Mexico. NOAA Photo Library

The term "deep sea" refers to parts of the ocean that are over 1,000 meters (3,281 feet). But in comparison to some areas of the ocean, 3,000 feet is shallow - the deepest parts of the ocean are more than 30,000 feet deep.

One challenge for marine life in this ecosystem is light - many animals have adapted so that they can see in low light conditions, or don't need to see at all. Another challenge is pressure. Many deep sea animals have soft bodies so that they aren't crushed under high water pressure.

Deep Sea Marine Life:

The deep sea is difficult to explore, so we're still learning about the types of marine life that live there. Here are some examples of general types of marine life you could find there:

  • Invertebrates such as crabs, worms, jellyfish, squid and octopus
  • Corals
  • Fish such as anglerfish and some sharks
  • Marine mammals - some types of deep-diving marine mammals are sperm whales and elephant seals.
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Hydrothermal Vents

Hydrothermal Vent / University of Washington; NOAA/OAR/OER
A black smoker community comprised of giant red tubeworms and hundreds of squat lobsters. This vent is located in Strawberry Fields of the Main Endeavour hydrothermal field on the Juan de Fuca Ridge. Vibrant colonies of tube worms with red gills thrive on this vent which is predominantly composed of iron- and sulfur-bearing minerals. University of Washington; NOAA/OAR/OER

While they are located in the deep sea, hydrothermal vents and the areas around them serve as their own ecosystem.

These vents are underwater geysers that spew mineral-rich, 750-degree water into the ocean. These vents are located along tectonic plates, where cracks in the Earth's crust occur. Seawater in the cracks is heated up by the Earth's magma, As pressure forms, the water is released, where it cools and the minerals deposit around the hydrothermal vents.

Doesn't sound like a very welcoming place to live, does it? Despite the challenges of darkness, heat, ocean pressure and chemicals that would be toxic to most other marine life, there are organisms that thrive in these hydrothermal vent ecosystems.

Marine Life in Hydrothermal Vent Ecosystems:

  • Archaea - bacteria-like organisms that do chemosynthesis, which means that they turn the chemicals around the vents into energy. These organisms are the base of the hydrothermal vent food chain.
  • Invertebrates, such as tubeworms, limpets, clams, mussels, crabs, shrimp, squat lobsters and octopuses.
  • Fish, such as eelpouts (zoarcid fish)