Microfauna: what it is and examples - Summary and photos

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Microbial life forms make up most of the biota in the biosphere. Although they are not as noticeable as large beings, these microorganisms contribute the largest number of species and individuals to biological communities.

When talking about animals, most people think of creatures that can be seen with the naked eye. While mammals, birds, amphibians, and reptiles are the most popular representatives, they are neither the only nor the most abundant.

Edges and classes with smaller species such as insects, arachnids, crustaceans and mollusks, outnumber these larger animals in proportions that reach an impressive ratio of 1 to more than 200 million.

There are even smaller species of animals that far exceed this number. These animals, whose size is microscopic, make up the microfaunas of planet Earth. If you are interested in knowing more about the subject, read this Green Ecologist article in which we talk about what is microfauna and examples her.

What is microfauna

The term microfauna refers to the set of microanimal species that simultaneously inhabit a certain geographic region. Like the mesofauna, macrofauna and megafauna, it is one of the types of fauna that exist on planet Earth.

Microanimals are tiny animals that can only be seen and studied with the help of a microscope. They are smaller than 0.1 millimeters (or 100 microns) in size, although species up to 0.199 millimeters in size (or 199 microns) are considered by many to be part of this group as well.

Some authors state that the microfauna is composed both by microanimals and protozoa (belonging to the Protista kingdom). This cannot be considered true if we conform to the literal definition of the word microfauna; because micro- means small and -fauna means animal.

Characteristics of the microfauna

Based on this concept, we can make some characteristics of the microfauna:

  • Microfauna is part of the fauna of the geographic region to which it belongs.
  • The microfauna is part of the biocenosis of the ecosystem to which it belongs. It specifically encompasses within the microbiota.
  • The microfauna of a certain ecosystem also represents microscopic zoocenosis of the same.
  • All the animals that make up microfaunas they are invertebrates. This means that they lack a backbone and skeleton. You can read more about Invertebrate Animals: examples and characteristics in this other post.
  • The microanimals that make up the microfaunas possess all the characteristics of the animal kingdom. Among them we can highlight that they are multicellular organisms composed of eukaryotic cells, which feed in a heterotrophic way through ingestion, and which reproduce sexually (there are species that can reproduce both sexually and asexually). Read this article to know more about Heterotrophic Organisms: what they are, characteristics and examples.
  • The microfauna of a given ecosystem forms part of microbiocenosis of the same.
  • Microfaunas are part of all terrestrial ecosystems and biomes. To facilitate their study, they are included within microecosystems and microbiomes. If you want to know more, here we leave you this other article with the explanation of the Differences between ecosystem and biome.

Main representatives of microfauna

Next, we go to the main types of microfauna that exist:

  • Nematodes.
  • Copepods.
  • Rotifers.
  • The tardigrades.
  • Loricefers.
  • Diplostraceans.
  • Some species of mites.
  • Microscopic juvenile specimens of some species of insects, arachnids, annelids, crustaceans, and mollusks. If you want to know more about Mollusks: characteristics, types and examples, do not hesitate to visit this article that we recommend.

Here we will explain some of the most common microfaunas that exist on Earth.

Edaphic microfauna

The edaphic microfauna, terrestrial microedafofauna or microfauna of terrestrial soils is one that is present in all soils of the earth's surface. The microanimals that compose it are essential for their geographic regions because together with other types of microorganisms:

  • Let it be decompose organic matter and certain types of inorganic matter.
  • They make it possible to perpetuate trophic chains and the cycle of energy and matter. Do not hesitate to read this article on What is a food chain and examples to know more about it.
  • They make it possible for nutrients to be used and soils to be fertile.
  • They favor the micro and macroflora proliferate.
  • They allow the populations of certain pathogenic microorganisms to be kept under control.

The main representatives of the edaphic microfauna are nematodes, known colloquially as roundworms or cylindrical worms. If you want to know more about What are nematodes: characteristics, classification and examples, visit this other article.

Marine microedafofauna

The microscopic infauna, microfauna of marine soils or marine microedafofauna is the one that is made up of all those benthic microanimals that inhabit the interior and surface of ocean floors. They are of vital importance for aquatic ecosystems because:

  • Serve as food for many species larger.
  • They help decompose organic matter: if you want to know what organic and inorganic matter is and examples, we recommend this article by Green Ecologist.
  • They allow the soil fertility from the seabed.

The main representatives of the marine microedafofauna are nematodes, rotifers, copepods, ostracods and tardigrades.


Microzooplankton is the type of zooplankton formed by aquatic animals whose size ranges between 0.02 and 0.2 millimeters (or 20 and 200 micrometers respectively). Unlike benthic microanimals, microzooplankton mainly inhabit water columns.

It is part of the microplankton and plankton of the aquatic ecosystem to which it belongs and is the common microfauna of all bodies of fresh and salt water in the world. It is of vital importance for aquatic biomes because:

  • It constitutes the base of the food chain of aquatic ecosystems: together with micro-plankton, it serves as food for hundreds of thousands of species and decomposes organic matter. You can read this article on What is an aquatic ecosystem.
  • It plays a fundamental role in various biogeochemical cycles: among them that of energy and matter, and that of oxygen and nitrogen fixation.
  • Is a quality bioindicator and the water pollution level.

Although the species that make up the microzooplankton can vary according to:

  • The geographical location.
  • The depth
  • Temperature.
  • Other physicochemical factors of water.

Still, it is essentially composed of nematodes, rotifers, ostracods, copepods, tardigrades, and other microscopic invertebrates and their larvae.

We leave you this article on What is zooplankton so that you can complete your information on the subject.

Microfauna of an aquarium

Veterinarians, biologists and aquarists from all over the world affirm that in order to maintain the health of an aquarium's ecosystem, it is necessary to regulate its microfauna in an artificial way.

If you have an aquarium, you must introduce and control populations of certain microanimals that are beneficial for its biocenosis: they are called benign microfauna. Among them we can highlight certain species of rotifers, copepods and other types of microscopic crustaceans. Some of its functions are based on:

  • It serves as food for corals, crustaceans and some species of fish.
  • Helps eliminate pathogenic and / or unwanted algae, bacteria and protists. Are algae plants? Discover the answer in this Green Ecologist article that we recommend.
  • It purifies water by feeding on waste and decaying organic matter.

Here you have more information about What is biocoenosis: explanation and examples.

Microfauna of the human body

The microfauna of the human body is made up of all those micro-animals that inhabit our body. They are part of the zoocenosis of the human body and can be beneficial, harmful or commensal.

Our digestive system, skin and eyelashes are some points of concentration of various species of micro-animals. Some of them are:

  • Dust mites: When we sleep, the dust mites found in our beds get into our bodies and consume our dead skin cells.
  • Skin mites: some people have mites of the species Demodex brevis Y Demodex folliculorum on your eyelashes, hair follicles, and / or oil glands. Sometimes these micro-animals can cause annoyance to their guests.
  • Scabies mites: scabies or scabies is a skin disease caused by mites Sarcoptes scabiei. Males of this species measure 150 to 250 microns.

Finally, it is necessary to comment that our intestinal microbiota is made up of several species of micro-animals. Some are beneficial and aid digestion, while others are parasitic and can cause discomfort and illness.

If you want to read more articles similar to Microfauna: what it is and examples, we recommend that you enter our Biodiversity category.

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