Marine Algae: characteristics, classification, benefits and more…

Marine Algae are organisms that are able  to  carry out the process of photosynthesis; using energy provided by the sun light.  These plants live in aquatic environments , mainly  in the sea;  but some species can be found  in freshwater. It all depends on the species.

They  can be unicellular or multicellular, and they are eukaryotic organisms; which means their cells have a cytoplasm.

According to investigations,  these organisms  were the first vegetables that existed  , taking into account all their evolutive process .

There is a wide variety of species, types ,and groups of  marine algae, which  have different characteristics. So their  size, color, habitat, nutrition and even reproduction, are quite variable.  Now, since algae are highly recommended for human consumption nowadays,  we invite yoy to read all the information we have for you.

Main Characteristics Of Marine Algae:

Following, you will find  the most outstanding characteristics of  these plants, which have become really popular  and useful in recent years.


Algae  are mainly autotrophic organisms , which means they can synthetize all the required substances for their metabolism. Although  there are cases in which algae, also  have the capacity to feed themselves in an heterotrophic way.  This means they need of others organisms.
It should be noted that they  play a fundamental role in the aquatic ecosystem, since they are the main primary producers. This is to say, they are  the base of the food chain that supports many species of marine animals.
Now,  the algae don’t  take their nutrients from the soil on which they are fixed.  These organisms feed  themselves, from the nutrients provided by the liquid environment where they live, thus the nature of their food  varies, according to whether they have chlorophyll or not.

Then, the process that takes place in marine algae that have chlorophyll; is to decompose the carbonic acid that is dissolved in the water.  They carry out this process,  using  light rays provided by the sun. In contrast, in the case of algae that don’t  have chlorophyll, , they feed from beings of their marine environment, such as animals and fungi. In these cases, it should be noted that many algae live parasitically on the bodies of other animals or plants.

Another important aspect to understand this process, is that algae don’t  metabolize nutrients by circulation; all this is carried out by means of cell-to-cell absorption.  This is the reason why if we find algae outside the water, the upper part will be dry. The lower portion  of their  structure, which  is in contact with  water, remains healthy.

According to several studies, each species of algae are placed at  specifics  depths.  This  location is determined  by   their sun light, pressure and temperature  requirements, to develop the  process of  photosynthesis. Thus,  algae never leave, their ideal depth.


There are more than 30,000 species of algae,  with their corresponding characteristics of size. It can range from microscopic  to giants  species, which measure about one hundred meters. Given the high number of algae species, we will find many differences between each one of them.   There are unicellular  and microscopic species, as well as colonial species,   that have the ability to develop complex anatomies.  Therefore , it’s a complex task, to list the characteristics of every algae according to their specific size,  since there are many differences among each species.


The characteristic color is quite varying, among every species;  since it depends on the pigments located  in the plastids . So, chlorophyll for example  is green, the phycoerythrin is red,  the  fucoxanthin is brown,  carotene is orange, phycocyanin provides blue  color and finally zeaxanthin is yellow. Then according to each species, and its particular pigments, its  final color will be determined

Marine Algae : Diatoms

Clasification of Marine Algae

To explain about  the classification of marine algae, it is necessary to mention  that they constitute a polyphyletic group. This  means it is  constituted by the artificial union of scattered branches of the evolutionary tree.

Then, to understand their classification , we proceed to take into account their pigments, in conjunction with the substances they have in reserve. Their characteristic  cell wall and  cell division, are also considered. According to these aspects, it can be said that there are prokaryotic autotrophic algae and eukaryotic algae.

Prokaryotic Autotrophic Algae

This group is comprised  by  Cyanobacteria , which belongs to the  sort of bacteria. These algae are photosynthetic and have chlorophyll, as well as phycobilins  as an auxiliary pigment. This group was commonly denominated by scientists as “cyanophyte”  or «blue-green algae«, but today this term is limited to algae,   in the case of eukaryotes.   The expression of blue-green algae has been considered as obsolete, and its use is therefore dismissed. All  this,  since the difference between an  eukaryotic cell  and a prokaryotic one was discovered , so it  confirmed that these were the unique prokaryotic algae. ( the cyanobacterias).


 Eucaryotic Algae

This type of marine algae, is included within the Protist  Kingdom or classification.  These organisms are photosynthetic autotrophic beings; since they have the capacity to create organic matter,  employing light energy and inorganic matter. Therefore,  they  are usually considered as plants in some classification systems.
It is important to mention that this type of marine algae, can be unicellular or multicellular. They have a cell wall that is formed by cellulose molecules; which is their main  characteristic.  In the case of some multicellular specimens,  cells are organized into tissues. In turn, the structure already formed is called talus.

According to  many specialists , the most common definition that can be attributed to these marine algae, is » photosynthesizes eukaryotic organisms ,by chlorophyll associated with other pigments located in the chloroplasts,  which reproduce by spores or gametes,  produced in sporocysts or gametocysts . They live in the water or in very humid environments»

We invite to watch this video, so you can learn interesting things about algae

Most Common Types of  Marine Algae

As youl will note following, algae are classified  according to their distinctive color, so their  pigments  willl be the main aspect…

Green Algae

This group has about 10,000 different species, being undoubtedly a very diverse group . In turn, they are related to terrestrial plants. Although they can  be found in the sea, these algae are actually more common in freshwater, covering a wide variety of habitats. Only 10% of the species that make up this group are found in salty waters. On the other hand, those that live in the sea, are located where the rays of the sun can arrive, so that they can carry out the photosynthesis ,as well as the processes of nutrition and development.

Most  of these species are unicellular, mostly flagellated, but there are also cases, where they develop  basic pluricellular structures. It’s important to mention that they are often  related to the terrestrial plants, since they  are very similar.   This is due to the presence  of  pigments like chlorophyll, in addition to carotene and xanthophylls.  They also  have starch as their  reserve substance

It is also known that these  species of algae ,can be found in habitats of very adverse situations. They can even  develop in the air, in very humid environments. Most of the species in this group are benthic, meaning they are linked to the bottom of the surface; but there are also cases where they are planktonic, which means they can live in suspension.

Regarding their reproduction,  they are able to reproduce asexually, by means of mobile spores. Although there are cases, when they also reproduce sexually, through the fertilization of an oosphere , which is the female gamete, by a male gamete frequently flagellated, which is the spermatozoon .

Red Algae

This group of red algae  is as important as the previous one. About 7000 species make up it , with a wide range of shapes and sizes. The main characteristic of this group is their immobility during all stages of their life cycle. This is because they don’t  have flagella.

Their plastids contain two membranes, chlorophyll, al well as   accessories  pigments of carotenoids and phycobiliproteins. These last two pigments  hide the color of chlorophyll and result the  distinctive red color of this species. Moreover, these algae are mainly located in deep waters.

Note that most of the species of this group  live in the sea, and  only 164 species live in fresh water. The  habitats  and the ecosystems  where they develop, go from intertidal areas to even very deep waters, all this depends on the transparency of the water. So, red algae can live at depths that range from 100 meters to 250 meters.

Finally the obvious conclusion is that the algae of this group ,  are the most abundant in  depths. This is because their pigments give them the ability to capture,  the wavelengths of the sun’s rays that penetrate deeper into the water.

marine algae: red algae

Glaucophytic  Algae

This is a small group of algae that is made up of about 13 species, all of them unicellular beings, which is  its main characteristic.  On the other hand this group of glaucophytic   algae,  are characterized by the presence of “cianelas”, that is to say the plasts  that perform  the photosynthetic function,  as in the case cyanobacteria, and the absence of chloroplasts. The  reproduction  of these algae is  not sexual , but  rather it is carried out through bipartition.

Brown Algae

These  algae belong to the kingdom of  Protists,   with approximately 265 genres  of about 2000 species, mostly seaweed. Only six genres  of this group inhabit in freshwater. It is important to mention that this group of brown algae are considered as the main primary producers, forming the basis of a food chain; that is made up of several species of animals within their ecosystem.

In relation to their habitat, brown algae are mostly located on rocky shores of temperate zones, even in sub polar areas. So  they predominate in intertidal zone as is the case of the “Fucales”  and «Laminarials»  The brown algae, can reach up to 60 meters length, and they float  in the water freely , which are also outstanding  characteristics.

On the other hand, it must be taken into account that brown algae have pluricellular forms with differentiated tissues between different species and genera. In general terms, it is known that they have pigments   like chlorophylls and also fucoxanthin, this results in their characteristic brown color 

Regarding to the shapes and sizes, there is a wide variety in this species. There are very small members in this group that consist of only a few cells, therefore microscopic algae are formed. Others members grow not a little more than a few centimeters long.

Other groups of brown algae , grow to sizes much larger than   the previous mentioned, for example, kelp algae  which are usually the most visible algae in their respective habitats. So, their size can vary from 50 centimeters to 60 meters, which is the largest known size. This corresponds to the giant algae species of Macrocystis pyrifera.  There are also different shapes,  depending on each individual of this specie . We can find  from subtle strands of cells to wide and rigorous branches.

The visible structure of brown algae is known as thallus.

It is important to highlight, that they are the largest seaweed that exist. They also grow very fast. This growth usually happens diffusely, since the reproduction of the cells can be carried out in any part of the thallus.

Golden Algae

This group is made up of at least 1000 species, which are generally flagellated unicellular organisms, although many of these species form very elaborated colonies. Golden Algae live mainly in freshwater, but they can also be found in moist soil and even in the sea. In general, it’s very common to see them in lakes and lagoons that have clean,  fresh  and above all cold water.

In terms of nutrition, most of these algae are photosynthetic, although there are also cases of mixotrophs and heterotrophs. They have the ability to change photosynthesis by a heterotrophic lifestyle , when necessary. In this way, they can develop pseudopods in order to catch food, which is usually based on small protists.

Regarding  their  structure,  these algae present a wide variety in terms of morphology. Most of them  are unicellular beings, but they also have the capacity to group themselves in colonies, and in this wayconstitute  a more common structure with a branched stem. It is known that their  reproduction can be sexual or asexual.

Green-Yellow Algae

This small group of algae consists of about 600 species, these can be found mainly in continental waters and soil, although some species are also marine. Some of the species are unicellular and others can be grouped into colonies.

Regarding their structure,   green-yellow algae  can occur in unicellular and sometimes flagellated forms. Although these species usually tend to group in filament colonies that can be simple or branched. They can also be found  in palmeloid states. It should be noted that they don’t  form mobile colonies, but flatulent gametes or zoospores may also appear

Benefits of Marine Algae

It has been shown that algae  provide great benefits to the people who consume them. Thanks to discoveries, of studies developed in places where they are consumed in  big amounts;  it was demonstrated that people get to live longer in a healthy way.

We show following , the main benefits that can be highlighted: they are completely remineralizing, this positively influences the health of bones and helps the general biochemical functionality of the organism. In addition, marine algae can stimulate the proper functioning of the thyroid gland;  for this reason the  metabolism is improved. Although, people suffering from problems with these glands , should avoid their consumption without specialized  supervision.

These amazing plants   also have alkalizing properties, which certainly help compensate the acidosis, caused by  excess in the consumption of red meats or highly processed foods. We must also mention, that they have depurative properties, since they help to clean the blood. Their capability to  stimulate the correct functioning of organs,  such as kidneys and liver,  and  to eliminate toxins that may be present in food, is also remarkable.

But  that’s not all, since marine algae also have positive effects on the physical aspect. It has been confirmed that their consumption improves the skin, hair and nails;  keeping them in a healthy state.  We could mention  for example diatoms algae . Marine algae are also useful to lose weight and to eliminate  fat concentrations;   even mucus deposits that can be created by excess of milk consumption.

Main properties of Marine Algae

Marine and freshwater algae,  have many beneficial properties,  that should be noted. They  are considered as the oldest plants in the world, which make them rich in vitamins  and minerals. This is their main  advantage, when comparing them with other vegetables.

In addition,  we should mention that  compared to fish, algae don’t absorb too  much pollution;  because if they are in a polluted habitat, they simply don´t  grow or develop. Therefore, they can be considered as an organic and clean source of the main nutrients.

All species of marine algae are considered to be rich in iron and calcium; they are listed as one of the richest vegetables regarding  these minerals; which is probably  their main benefit.  They are also known for having significant amounts of magnesium and potassium.

They also contain alginic acid, which according to several studies contributes to eliminate naturally,  some toxins and heavy metals outside the body. In addition to these important contributions, they are also  rich in vitamins, specifically in vitamin A, group B (except vitamin B12), also C, D, E and K.  Their content of proteins  and  carbohydrates, is quite significative.

We give you this video, for you to learn about the Uses of  Algae:

Preparing Marine Algae For Consumption

First of all we must say that all algae are edible; so every person can select the more pleasant alga, according to  his likes.  You shoul also know, that all   algae are sold already dries;  this certainly facilitates their  storage and their  posterior use, since it is recommended to preserve  them in this form. They can be stored and conserved  in this state,  for long periods of time without losing  their main properties.

Algae  are not  usually sold in traditional supermarkets; so you can find   them in specialized  places, such as  organic stores. Among the most common ones   for consumption, we can mention  wakame,  kombu, arame, as well as nori, dulse, hiziki and agar-agar.

Before preparing the algae , it is necessary to  soak them , in most  cases a few minutes will be enough. Depending  on the species and  type, they should also be cooked. It is important to know, that once algae have been  purchased; the best way to preserve them before being used,  is in a sealed tight container.

Another aspect you should consider   before buying algae, is that once they have been soaked  they usually grow considerably. Once you become familiar to different types of algae , you could buy  the proper amounts,  according to your needs. Howerver  before this happens, the best thing is to buy small quantities.  Finally it is very important that before soaking the algae,  you should wash them thoroughly with plenty of cold water.

Seaweed are  usually included in dishes such as salads, soups, even stews. Although there are many others ways to include them in recipe preparations, these meals must be the first options for beginners . Their consumption usually depends on the particular likes  of every person.  The nori seaweed    is usually taken into account, since it is quite used for preparing Sushi….

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