Everything You Need To Know About Cyanobacteria

Cyanobacteria are a species of Gram-negative bacteria that gets their energy via photosynthesis. They are blue-green algae and have also been known as blue-green bacteria.

They need basic environmental states and can originate in various domains, such as marine and terrestrial areas. They are microscopic organisms, however, they also appear in macroscopic settings when they appear in colonies in the water.

Everything You Need To Know About Cyanobacteria

Cyanobacteria are also made up of many bacteria species found in various areas. These bacteria are spread around 150 groups that have currently been identified and play multiple essential parts in nature.

These bacteria are microscopic organisms that occur naturally in nature, and it doesn’t matter what type of water that they reside in.

They multiply incredibly quickly and can create blooms that will quickly spread across the surface of the water and may also become visible.

These can occur in slow-moving waters or even in septic tank overflows. You’re likely to find them in late summer or in the early days of fall.

Cyanobacteria can be harmful to both humans and animals, and there are even steps taken by the Centers for Disease Control regarding what you should do if you come into contact with cyanobacteria in water.

In this article, we’ll explain to you what cyanobacteria is and how it can be harmful to humans.

By the end of this article, you should be able to identify types of cyanobacteria, where they may naturally occur, and what harm they can do to both humans and animals.

You will also learn about the different classifications of cyanobacteria and how you can treat infections from cyanobacteria toxins.

First, let’s discuss some examples of cyanobacteria so you know what to look for when you see it if you see it in the water and what you should do if you find it there.

Examples Of Cyanobacteria

Here are four distinct examples of cyanobacteria and how they can affect humans if they are ingested accidentally.

Microcystis aeruginosa is a species of freshwater cyanobacteria that forms harmful algal blooms to both humans and animals through contact with the body, accidental ingestion, or water droplet inhalation.

Cylindrospermopsis raciborskii can be found in freshwater areas and can cause negative health effects on humans.

Anabaena circinalis is a common freshwater cyanobacterium that, if ingested in small amounts, could cause gastrointestinal distress, but in large amounts, it could cause serious neurological damage.

Nostoc commune is otherwise referred to as star jelly and could produce biologically active secondary metabolites that are incredibly toxic to both humans and animals.

Now that you know some examples of cyanobacteria, we’ll explain what the characteristics of cyanobacteria are and the orders in which they’re grouped.

Characteristics Of Cyanobacteria

Cyanobacteria have considerable structural diversity, and because of that, they have species that are characterized by shared close characteristics.

In this section, the characteristics of cyanobacteria have been placed in separate groups based on the orders under species for their respective attributes.


The Chroococcales Order is formed by the classes known as Entophysalidaceae and Chroococcaceae.

The species of these groups are either spherical or rod-shaped. Many of the Entophysalidaceae have a larger representation of spherical organisms.

Other characteristics of these organisms are that they procreate via binary fission. They also establish colonies to establish concentrated masses that are viewable on surfaces, especially on wet rocks.

Chroococcales share these common characteristics among them, including a spherical shape structure of their cells, with the addition of ovoid and cylindrical structures.

They may also occur singly after the dividing of cells. You will find that the Order Chroococcales configure colonies which are bonded by a viscous matrix as they reach maturation.

Members of Order Chroococcales are Aphanocapsa, Gloeocapsa, Merismopedia, Microcystis, and Pleurocapsa.


Order Gloebacterales contain organisms from the members of Gloeobacter.

They have phycobilisomes which are light-harvesting complexes. Thus, members of Order Gloeobacter lack any thylakoids that are seen in other cyanobacteria.

However, similar to other cyanobacteria, you can find them in a range of environments, such as on limestone rocks and other aquatic areas.


Order Nostocales members are similar to the Order Stigonematales in that they have a heterogeneous cellular composition in their trichomes.

Their vegetative cells are separated into heterocysts which appear to have a thick hyaline protoplast and are included in nitrogen fixation.

Additionally, they have akinetes that have a thick cell wall in place, which permits them the ability to survive in unfavorable conditions.

Another trait that separates Order Nostocales members from others is that false branching will occur in certain species in this Order.

Members of Order Nostocales include Anabaena, Calothrix, Cylindrospermopsis, and Nostoc.


Order Oscillatoriales are comprised of threadlike cyanobacteria, which have uniseriate filaments. Yet, many members of this grouping share an absence of true branching, akinetes, and heterocysts.

Members of Order Oscillatoriales can be seen in an assortment of domains, including fresh and saltwater expanses to terrestrial areas.

More traits of the Order Oscillatoriales are that they have a tendency to construct multicellular structures that appear elongated and that they have a fibrous appearance.

Members of Order Oscillatoriales include Lyngbya, Microcoleus, Phormidium, and Planktothrix.


Order Pleurocapsales are unified by the ability to procreate via multiple fission, and they also release endospores.

In comparison to other entities that can form endospores, the members of Pleurocapsales are distinguished by their ability to separate via binary and multiple fission.

Led by an expansion of spores, supplemental binary fission occurs so that a barrage of vegetative cells are produced. A few of these cells will continue via multiple fission to distribute more endospores.

Order Pleurocapsales comprises an assortment of organisms found in a vast range of habitats that range from marine to terrestrial domains.

Through development, a few members of Order Pleurocapsales have been observed to evolve as epiphytes on algae and epiliths on surfaces that include wet rocks.

Members of Order Pleurocapsales may also have pseudo-filaments that have the ability to multiply via baeocytes.

Members of Order Pleurocapsales include Chroococcidiopsis, Dermocarpella, Pleurocapsa, and Xenococcus.


Order Stigonematales have a portion of interchangeable traits to members of the Order Nostocales. Traits these share include trichomes that have a heterogeneous cellular arrangement and heterocysts, akinetes, and vegetative cells.

Other traits that are only related to the Order Stigonematales count them having many filaments with true branching occurring.

Members of Order Stigonematales include Mastigocladus and Stigonema.

Now you should understand the characteristics of the different orders of cyanobacteria and the differences between them. Let’s discuss how cyanobacteria are classified and when this first occurred.

Classification Of Cyanobacteria

Everything You Need To Know About Cyanobacteria

The proposed classification of cyanobacteria occurred in 1985 when scientists took its Bacteriological factor into account. Four Orders of cyanobacteria were proposed, including Chroococcales, Nostocales, Oscillatoriales, and Stigonematales.

Since then, other orders have been discovered, including Gloebacterales and Pleurocapsales.

These bacteria also fall under the Kingdom of Monera and in the Eubacteria Division. There have been advances in how cyanobacteria have been classed, which has caused major debates at higher taxonomic levels.

While initially they were classed as blue-green algae due to their possession of chlorophyll and their algae-like appearance, further studies have noted that they are actually prokaryotic, and thus, cyanobacteria were able to be re-classified appropriately.

However, even with proper classification, how should you treat cyanobacteria toxins with treatment?

Cyanobacteria Toxins And Treatment

Cyanobacteria produce a large range of different compounds, with 2-methylisoborneol and geosmin as distinct examples. When they’re released in water, these compounds result in a change in both taste and odor.

Apart from these compounds, they have been observed to produce toxins such as hepatotoxins, neurotoxins, and dermatoxins.

These are then released by planktonic species and can have a negative impact on humans and can cause liver infections, infections of the nervous system, and skin irritation.

Cyanobacteria are also responsible for microcystins, which are cyclic peptides that could either contain seven amino acids or alternative constituents that look like amino acids.

These compounds are then synthesized by enzyme complexes. The toxin produced through this process can cause serious health issues and the death of metazoa.

Due to these toxins, cyanobacteria appearing in drinking reservoirs can be a great concern due to the serious health impacts they have on all animals and human beings.

While a few of the toxins are released in water, these bacteria have been observed to release potent toxins, including anatoxin-a, produced by Anabaena flosaquae, which can cause death within half an hour.

Some toxins are capable of causing paralysis and have been identified in blooms and may also result in death.

After contacting algal blooms, these toxins can cause allergic rhinitis and dermatitis, among other symptoms.

Bloom-forming species tend to be discovered in habitats with favorable conditions, such as warm, stable, and high nutrient levels. Some organisms identified here include members of Anabaena, Microcystis, and Aphanizomenon.

A few of the symptoms in humans include Diarrhea, Pilo-erection, vomiting, general weakness, cold, and death.

Effective treatment for cyanobacteria toxins has yet to be developed, so prevention is the best cure.

To prevent infection, it is best not to drink water from lakes or rivers, especially if there’s the possibility of blooms and scum in the water.

You should also not use those types of water for cooking or refreshment preparation, as they may contain toxins.

Some may think boiling water is safe for consumption, however, it is not recommended because doing so may increase the effects of these toxic substances.

Depending on the infection and what type of cyanobacteria infected you, the methods of treatment can include antibiotics, intravenous electrolytes, oxygen therapy, vitamins, and drugs such as cholestyramine.

However, the means of this treatment have mostly been tested on dogs.

Understanding how you can prevent an infection from cyanobacteria can be vital to ensuring your survival. But, it would be best to understand how cyanobacteria can form in nature.

Occurrence Of Cyanobacteria In Natural Habitats

The species of cyanobacteria is comprised of assorted parts. Numerous traits have appeared in almost every member of the cyanobacteria species.

Cyanobacteria is versatile and can adapt to many alternative environments, even ones that they would not naturally acclimatize to.

Many types of cyanobacteria are aerobic photoautotrophs. Due to this, they have a strong reliance on water, carbon dioxide, sunlight, and other miscellaneous inorganic substances to ensure their survival.

To get energy, cyanobacteria rely on photosynthesis, and they are dependent upon sunlight, carbon dioxide, and water to succeed. To survive, a number of them have been observed to adapt via numerous mechanisms.

One such example is how they included ultraviolet absorption through sheath pigments which allowed for some cyanobacteria to survive environments that were exposed.

They are predominant in hot and cold springs and other marine environments where microalgae cannot survive.

The reason that cyanobacteria can survive is that they can adapt to alternative environments.

Cyanobacteria enact a vital role in the microbial community, as they can be discovered almost anywhere on Earth.

However, due to some unsustainable environments, other living organisms are unable to thrive, including deserts, hot springs of a higher temperature, and Antarctic ice shelves being among these areas.

Due to this, they are required to adapt to help themselves survive in these conditions.

Along with the ultraviolet absorption of sheath pigments that were discovered in a few species, planktonic cyanobacteria were discovered to persevere in Ultra Violet Rays by drifting or submerging into their environment through the use of gas vacuoles.

For members of the Order Oscillatoriales, chances of survival can be increased by actively going from microbial mats and into matrix sediments to get more advantageous conditions.

These allow members of Order Oscillatoriales to endure Ultra Violet Rays. When they appear in Antarctic Lakes, cyanobacteria were observed to have significantly lower consumption of oxygen.

Chlorophyll and its presence are one characteristic identified, additionally, they have a variety of other extra pigments, including allophycocyanin, phycoerythrin, and phycocyanin.

By having these pigments, they play a vital role in effectively utilizing the spectrum of light in a specific region or environment.

Should there be a variety of light spectrums, cyanobacteria can still continue photosynthesis to increase their chances of survival.

They are also capable of carrying essential nutrients and metabolites inside their cytoplasm. By incorporating this and having dinitrogen fixations, they can continue to have the necessary nutrients needed to survive.

Including other mechanisms, the bacteria are then able to endure in deep, sunless environments for an extended amount of time.

Throughout these adaptations, members of cyanobacteria have been known to be able to thrive in both suitable and harsh environments on Earth.

Alternative survival strategies utilized include the capacity to adjust carbon dioxide at incredibly low water potential.

They also produce compatible solutes that are made by water-stressed organisms and mucopolysaccharides, which slows down liquid flow in the midst of freezing and thawing.

As you can see, cyanobacteria can thrive even in environments where you would not expect it.

Understanding the steps to take to prevent it will ensure that you won’t be in danger. However, there have been cases with cyanobacteria that have established a symbiotic relationship with other eukaryotic plants.

Symbiosis With Cyanobacteria

Due to heterocystous cyanobacteria’s capacity to adjust nitrogen, they commence symbiotic relationships with a miscellany of eukaryotic plants, for example, algae, angiospores, ferns, liverworts, and many others.

Studies observe that the symbiotic relationships with free-living cyanobacteria and eukaryotic plants resulted in biochemical, morphological, and physiological modifications, which caused a transmutation to the native configuration of the bacteria.

In the midst of nitrogen fixation, the nitrogenase enzyme transfers three pairs of electrons and protons to the nitrogen molecule to produce two ammonia molecules, which are then put on the glutamic acid to develop glutamine inside the plant’s cells.

In turn, amide nitrogen is provided and utilized for the synthesis of amino acids and components of DNA and RNA.

In this relationship, cyanobacteria are nitrogen-fixers who benefit from the carbon dioxide fabricated through the host.

Due to symbiosis with fungi, cyanobacteria produce an association known as lichens. The lichenization between cyanobacteria and fungi was reported for around ten percent of every lichen.

As fungi cannot conduct photosynthesis, the relationship connecting cyanobacteria and fungi is advantageous to fungi, as they can obtain different nutrients and energy through the photosynthesis of the cyanobacteria.

Now that you understand symbiosis, you should be able to understand the circumstances in which this occurs. However, what should you do if you’re identifying an infection?


Gram staining is used if you need to discover whether you have a bacterial infection.

To identify an infection, you need to discover whether your infection is either Gram-positive or Gram-negative. These tests can also be used to diagnose any fungal infections.

Cyanobacteria have Gram-negative structures, so they are unable to maintain the primary stain throughout the gram-staining process.

Scientists conducting a microscopic inspection of cyanobacteria have observed that there is an abundant layer of peptidoglycan in comparison to alternative gram-negative bacteria.

Investigations conducted on the peptidoglycan layer disclosed an increasingly complex structure in which the cross-link connecting the peptidoglycan chains is higher in comparison to other organisms.

Gram-negative strains of bacteria have been classed as more threatening by the CDC due to the dangerous resistance that they have to treatment.

They are more resistant to antibiotics, but many Gram-negative bacteria can’t survive on dry surfaces.

However, if any Gram-negative and Gram-positive bacteria are found, both can cause significant issues for anyone with a weakened immune system.

Final Thoughts

Hopefully, with the help of this article, you will have a better understanding of cyanobacteria and its characteristics and classification of it.

Due to appearing in both fresh and saltwater environments, alongside terrestrial areas, cyanobacteria is classified as a significant threat to both humans and animals.

If you ingest cyanobacteria, you could be in significant danger, and you should search for immediate medical treatment. The best way to avoid cyanobacteria is to stay away from any areas where you may find it.

Due to it being Gram-negative, it is highly resistant to antibiotics, and cyanobacteria have so many strains that they should be avoided.

By having a better understanding of cyanobacteria and how it can adapt and establish symbiosis with other organisms, there should be more treatments available in the future should cyanobacterium be ingested in the future.

Jennifer Dawkins

Leave a Comment

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