The cyanobacteria , also known by the name of algae blue – green , are an ancient group of photosynthetic microbes that can be found mainly in the waters . There are around 2000 species of them and they also have a wide range of shapes and sizes. They are classified within the Monera Kingdom and at present it is still debated whether they are prokaryotic or eukaryotic.

What are cyanobacteria?

Cyanobacteria are a very ancient species of organism that has the ability to carry out the photosynthesis process and also have a type of cellular structure equal to that of a bacterium .

  • Definition
  • Characteristics of cyanobacteria
  • Domain
  • Which kingdom do they belong to
  • Types of cyanobacteria
  • Structure
  • Nutrition
  • Habitat
  • Cyanobacteria function
  • Diseases
  • How they differ from eubacteria
  • Importance
  • Examples of cyanobacteria


Also known by the name of cyanophytes and they are a group of microscopic organisms that have the ability to carry out photosynthesis . They are a type of bacteria gram-negative also contains chlorophyll and are present in waters sweet, salty, brackish and estuaries. They have the ability to produce a series of dangerous toxins for humans and for this reason they are considered by the World Health Organization as a health problem that is on the rise.

Characteristics of cyanobacteria

Among its main features are the following:

  • They have the ability to produce photosynthesis .
  • They were previously known by the name of blue-green algae , cyanophiles or cyanophytes .
  • They can live in different types of temperatures .
  • They can produce a series of toxins in drinking water and in the seas which cause the appearance of diseases.
  • When they are massively growing, they can easily be seen as a green colored spot in the water.
  • They can produce a series of diseases that damage vital organs such as the liver and can also cause abdominal pain, vomiting and diarrhea.
  • Depending on the type of cyanobacteria, they can damage the central nervous system causing paralysis, cardio-respiratory arrest and death.
  • They promote the development of cancer and degenerative diseases .
  • Are reproduced so asexual , however , also they have some unique mechanisms of reproduction as binary fission , the multiple and budding .


The domain to which cyanobacteria belong is known by the name Bacteria or oxyphotobacteria , a name given to them because they have the ability to carry out the photosynthesis process.

Which kingdom do they belong to

They are under the dominion of the Monera Kingdom , in the eukaryotic division and in the class of cyanobacteria.

Types of cyanobacteria

The types of cyanobacteria that exist are the following:


The species of cyanobacteria that belong to this group have a spherical, ovoid, cylindrical or rod shape and can reproduce through binary fission, thus creating colonies that form high-density masses which resemble wet rocks on the surface of the Water.


They are characterized by reproducing through multiple fission and when they do, they release large amounts of endospores. They can be found in both marine and terrestrial environments and can develop as algae on wet rock surfaces.


It is composed of mostly filamentous cyanobacteria but they do not have a true branching. They can be located in various types of environments, in fresh water and on land.


They have a very homogeneous type of cellular composition and have very thick cell walls that make it difficult for them to survive in unsuitable environments.


They have a fairly heterogeneous type of cellular composition and also have vegetative cells.


Cyanobacteria have a relatively larger structure than bacteria and are prokaryotic. They have a peptidigian wall , DNA is exposed and has ribosomes . It does not have any type of union between membranes such as mitochondria , plastids , lysosomes and vacuoles . It has a cell wall that has four different layers and on the outside it contains a chloroplast . Chlorophyll , carotenes and xanthophylls can be found in their membranes .


Most cyanobacteria are autotrophic beings and some of them can also be heterotrophic. In some cases, cyanobacteria can feed by their parasitic form that allows them to acquire nutrients from their hosts.


Their adaptability to live in different types of habitats is quite large and they can also tolerate extreme conditions. They practically inhabit anywhere on Earth in marine, freshwater, snow, and host environments when they are part of a symbiotic relationship. Even in volcanic ash and areas with the presence of anthropogenic disturbances it is possible to find them. As for climatic zones, they can perfectly inhabit temperate , tropical and polar zones .

Cyanobacteria function

Cyanobacteria have the function of participating in approximately 30% of the photosynthesis that occurs on the planet daily and they also form an important part of the composition of the atmosphere . They play an important role in the proper development of plant life , to better understand it we can say that the chloroplast that is inside a plant cell and that produces its food is basically a cyanobacterium.

It has the ability to process nitrogen from the atmosphere and then convert it into an organic form, this process is of utmost importance for many plants to grow properly. They fix nitrogen to soil , coral reefs, and different environments in the water, making nitrogen available to many types of ecosystems .


Cyanobacteria produce a large number of toxins that are known as cyanotoxins . These are related to health problems in animals and humans and for this reason making the water that is contaminated with them drinkable is essential to prevent the appearance of diseases. Some of them are hepatotoxic and others neurotoxic , which means that they can perfectly damage important organs such as the liver and neurons , they can also cause serious irritation to the skin and mucous membranes .

The easiest way to contract some type of disease caused by cyanobacteria is the sea because they accumulate as a green layer on the surface of the water, so it is very common for people to have contact with it and even reach to ingest it, especially in the case of young children .

How they differ from eubacteria

Cyanobacteria are practically a subgroup of eubacteria , specifically those that can obtain energy from the photosynthesis process, a process by which they can produce oxygen and energy for their functions, also converting the nitrogen that is in the air into ammonia and nitrates. The eubacteria meanwhile, are basically bacteria having the ability to produce disease and as a power source utilize sunlight and inorganic compounds to produce the fuel necessary to carry out cellular processes.


They are of great importance because they have the capacity to be able to produce oxygen , to recycle nutrients and to capture the carbon and nitrogen found in the atmosphere. In addition, they work as a type of food for many of the herbivorous microorganisms , such as plankton , however, it also has the possibility of creating different types of problems associated with uncontrolled growth, so it is important to keep them well leveled and avoid contact with them.

In this regard, it is also of utmost importance to be able to make water drinkable to avoid their proliferation and to avoid their consumption and exposure. For this reason, having treatment plants to filter water becomes vital throughout the world since this is the best way to remove and disinfect water, thus preventing cyanobacteria from circulating freely and causing health complications.

Examples of cyanobacteria

Some examples of cyanobacteria are:

  • Arthrospiraplatensis also known as Spirulina.
  • Aphanizomenonflos-aquae which is grown as a food source and as a fertilizer.
  • Microcystis , Anabaena and Aphanizomenon which can cause serious diseases in the body.

Leave a Reply

Your email address will not be published. Required fields are marked *