Marine ecosystem

The oceans cover two-thirds of the Earth’s surface. Within this oceanic habitat live a great variety of organisms that have evolved in response to various characteristics found around them. Marine organisms are not found uniformly in the oceans. Different characteristics of the marine environment have created different habitats that influence the types of organisms that live in them. Light, depth, proximity to land, and topographic complexity affect all marine habitats. Within these depths we find the  marine ecosystem .

What is a marine ecosystem?

The marine ecosystem is part of aquatic ecosystems and can be defined as the interaction of plants, animals and the environment that is in the sea, and this type of ecosystem ‘s largest of 70% of seawater.

  • Characteristics of the marine ecosystem
  • Biotic factors
  • Abiotic factors
  • Fauna of the marine ecosystem
  • Flora of the marine ecosystem
  • Climate of the marine ecosystem
  • Temperature
  • Importance
  • Examples

Characteristics of the marine ecosystem

Some important characteristics of the marine ecosystem are:

  • They make up 70% of the earth’s surface.
  • They dissolve the salts in their own waters.
  • They provide humans with food and generate socioeconomic benefits .
  • They are within the category of aquatic ecosystems .
  • Includes seas, oceans, and marshes.
  • It has two types of regions: photic , which have light; and aphotic , which have no light.
  • They have great biological diversity .
  • The marine currents are in charge of mobilizing the nutrients for the development of the beings that inhabit the sea.
  • The water is thick .

Biotic factors

The biotic factors are divided into the following parts:

  • The producers are for example includes phytoplankton , diatoms , dinoflagellates, large marine algae, angiosperms and mangrove vegetation.
  • The consumers in turn are subdivided into:
    • primary consumers : are all those animals that feed on producers, such as crustaceans and fish.
    • Secondary consumers : carnivorous fish.
    • Tertiary consumers : they are carnivorous animals, but larger than the secondary ones.
  • Decomposers : are all those microorganisms such as bacteria and fungi.

Abiotic factors

They include the following aspects:

  • Ocean temperature
  • Light
  • Water salinity
  • Marine pressure

Fauna of the marine ecosystem

The fauna consists of all the animals and living beings that exist in the sea, regardless of their size. From the smallest like protozoa to large vertebrates like whales . They include a great variety of species, from mammals such as dolphins, manatees, otters to birds such as seagulls and pelicans, we can even find mollusks , starfish and crustaceans within the fauna . The turtles , although they are reptiles, also part of the marine fauna.

Flora of the marine ecosystem

In the marine flora there are a great variety of plants , mainly marine algae . The seas are full of them and each contains a large group of different life forms, some of them are so small that they can only be seen through a microscope. They have a varied way of life, some of them float and others and live fixed on the bottom of the sea or rocks, some can even fix some animals. They vary according to the regions of the world in which they are found and depend on the temperatures of the water in which they live.

Climate of the marine ecosystem

The climate in marine ecosystems is a type of severe climate , it occurs due to the different ocean currents that are in constant movement in the sea. These ocean currents are responsible for creating massive hurricanes and typhoons . Another determining role of the climate of the marine biome is the wind since it is the cause of the formation of large waves.


The temperature that we find in the marine ecosystem is very varied . Because it is the largest biome in the world , the climate ranges from -40 degrees Fahrenheit to over 100 degrees. The average temperature is 39 degrees Fahrenheit, but it is warmest near the equator where direct rays from the sun can penetrate the water and heat it. The lowest temperature water is located at the north and south poles , where the water is close to freezing . Also, the deeper the ocean, the colder the water will be because sunlight does not pass through it directly.


The oceans are one of the most important sources of oxygen for our planet and are essential for the capture and storage of carbon dioxide . The species of animals that live in the sea provide us with important ecosystem services, such as the provision of food , medicine and livelihoods . Also, the seas and therefore the ecosystems, are in charge of supporting tourism and recreational activities around the world. Unfortunately, the resources of the sea have been overexploitedby humans, which threatens marine biodiversity. The consequences of overfishing and habitat destruction are evident in many parts of the world, which can cause significant damage to ecosystems in an irreversible way.


  • Reefs
  • Shallow waters bordering the coastlines
  • Coast zones
  • Rocky shores
  • Estuaries
  • Coastal lagoons
  • Mangroves

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