Algae is a term that defines a large and diverse group of aquatic, eukaryotic organisms that can conduct photosynthesis. In addition to making a nutrient-rich food supplement, algae have a wide range of uses in the cosmetic, fuel, pharmaceutical, and textile industries. Algae is even used as a crop fertilizer and on space missions as bio or jet fuel. Algae’s functional benefits have increased its global demand and value lately.
In this article, we’re going to talk about all the types of algae in addition to everything else you need to know about algae.
What is an Algae?
Algae is an informal term used to describe a diverse group of photosynthetic aquatic organisms. These eukaryotic organisms range from unicellular microalgae like chlorella, unicellular microalgae, diatoms, prototheca to multicellular forms such as brown alga and giant kelp. This polyphyletic grouping includes species from various distinct clades, most being autotrophic.
Most species of algae are typically found in the aquatic environment and possess plant-like characteristics.
Just like plants, algae also contain chloroplasts and have the ability to perform photosynthesis. Algae occur in various sizes and forms, most of which are unicellular. Thus, they lack stems, leaves, and true roots along with a vascular system that circulates nutrients and water throughout the body. Algae lives in various environment, including fresh water, salt water, moist rocks, or wet soil.
Algae, as primary producers, lay the foundation of the food chain in the aquatic environment. From simple asexual cell division to complex forms of sexual reproduction, algae exhibit a variety of reproductive strategies. There are seven different algae types that have various traditional and industrial applications.
Because of their renewable, sustainable, and organic nature, algae make for a great economical fertilizer. Brown and red algae are the most extensively used algae as fertilizer, as they are rich in potassium.
There is various environmental, economic, and industrial importance of algae. It’s interesting to note that algae are the most important photosynthesizing organisms on earth. More than half of the world’s oxygen is because of algae, which is more than all the land plants combined. Algae capture sunlight to convert carbon dioxide into biomass and oxygen via photosynthesis. This means algae only need sunlight and carbon dioxide to grow, which is how algae grows so quickly, even in places where food crops can’t.
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Different Types of Algae
1. Chlorophyta (Green Algae)
Chlorophyta, commonly known as green algae or green seaweed, mainly grows in saltwater or freshwater. Chlorophyta can be multicellular, unicellular, coenocytic, or colonial. This alga is sometimes also found on moist land. Green algae have cell walls, and some species also have one or two flagella. There are 4,500 species of Chlorophyta that predominantly live in seawater.
Chlorophyta, or green algae, as the name suggests, contains chloroplasts and can conduct photosynthesis. They convert sunlight into starch which gets saved in their cell to be consumed as food. The green color of the algae is due to the abundance of chlorophyll A and B. The coloration is also determined by the amounts of xanthophylls (brownish or yellowish) and beta-carotene (yellow).
Uses of Green Algae:
Green algae have antibacterial, antiviral, and antioxidant properties. they are also rich in minerals that contribute to their high value and application in the medical industry. Along with being used in the medical industry as a highly used mineral, green algae are also extensively used in the food and cosmetic industry.
The benefits of green algae include its ability to purity air through photosynthesis (absorbing atmospheric carbon dioxide and releasing oxygen). As a major source of beta-carotene, green algae are used as a food coloring. Green algae have also been effective in preventing certain types of cancers like lung cancer. Chlorella is a great source of carbohydrates, protein, fats, vitamins, fiber, minerals, and chlorophyll. Chlorella is widely used in fibromyalgia, depression, menstrual cramps, and high cholesterol due to its amazing medical benefits.
Euglenophyta or Euglenoid is a division of highly differentiated flagellates that are saltwater or freshwater protists. Euglenoids are mainly autotrophic; they contain chloroplasts and can conduct photosynthesis. Heterotrophic euglenoids feed on other unicellular organisms and carbon-rich material in the water. This alga lacks cell walls and is covered by a pellicle (a protein-rich layer).
Euglenoid flagellates are predominantly found in ponds, lakes, puddles, streams, rivers, and ditches. Euglenoid cells mainly have two basal bodies along with two emergent flagella.
Uses of Euglenophyta:
Euglena is a food supplement containing Paramylon, which reduces uric acid levels in the blood, enhances immunity, and helps reduce cholesterol and fats. Euglena also increases the production of dermal fibroblasts and boosts collagen production. Euglena is also rich in nutrients and protein and thus is also used as feed for aquafarm fish and livestock. Besides this, euglena is also used as fertilizer and biofuel.
3. Chrysophyta (Golden-brown algae and Diatoms)
What is the most common type of algae, if you may ask? Here is the answer. Chrysophyta, also known as golden-brown algae and diatoms, are the most common type, with about 1000,000 different species. Gold-brown algae and diatoms are the most ecologically significant types in saltwater or the freshwater environment because they make the foundation of the aquatic food chain as a part of the plankton and nanoplankton.
Compared to golden-brown algae, diatoms are much more common and consist of several types of plankton in the ocean. Diatoms are encased by a frustule (a silica shell) instead of a cell wall. Depending upon the species, these frustules vary in structure and shape.
Golden-brown algae get their color from the pigment Fucoxanthin. They are encased in a statocyst or stratosphere (a silica cyst).
Golden-brown algae and diatoms contain photosynthetic pigment chlorophyll A and C. The usual form of reproduction in Chrysophyta is cell division, but they also reproduce sexually under some circumstances.
Uses of Chrysophyta:
Chrysophytes are used in manufacturing toothpaste, food fillers, food additives, and food thickeners. They are also used as biofuel because they store food in the form of oil. Chrysophytes are even used in the battery ionization process as stabilizers.
4. Pyrrophyta (Fire Algae)
Pyrrophyta or fire algae are unicellular algae that use flagella for motion. Fire algae are usually found in the oceans and some freshwater sources. They contain a pigment called luciferin that produces light without heat, which is why they are called ‘fire algae.’ Pyrrophyta have two ribbon-shaped flagella and are reddish-brown/yellow in color. They also contain photosynthetic pigment chlorophyll A and B.
Due to the abundance of dinoflagellates, a phenomenon known as red tide is caused, where the ocean appears red. Some species of Pyrrophyta are bioluminescent in nature, which makes the ocean appear to be aflame at night.
Apart from this, dinoflagellates are poisonous due to the presence of neurotoxins. The neurotoxin produced by dinoflagellates can disrupt muscle function in humans and other organisms. This neurotoxin can cause massive fish death. Cryptomonads, on the other hand, produce algal blooms, which are harmful and give a dark brown or red appearance to water.
Uses of Pyrrophyta:
Due to the toxic nature of pyrrophyta, they can’t be employed for commercial purposes.
5. Rhodophyta (Red Algae)
Rhodophyta or red algae are photosynthetic organisms of the kingdom Protista. Like other algae, these eukaryotic cells don’t have centrioles and flagella. They contain chlorophyll A and D, phycobilin, carotenoids, and xanthophylls. The red color of the algae is due to the presence of pigments called phycobilins.
The majority of Rhodophyta are marine species whose food reserve is Floridian starch. Out of 6500 identified species of red algae, 200 are freshwater species. Most of the world’s seaweeds belong to red algae. Red algae reproduce asexually by monospores as well as asexually.
They are found in almost all oceans but are most common in tropical climates. Rhodophyta occurs at great depths in the ocean compared to other photosynthetic organisms. Coralline algae that play a vital role in building reefs belong to Rhodophyta. Red algae are also a part of oriental cuisine. Nori seaweed is the most valuable marine crop grown by aquaculture, which is popularized by the Japanese.
Uses of Rhodophyta:
Agar that is used in dairy topping is extracted from red algae. Red algae are also the source of other phycocolloids used as thickening agents, such as furcellaran, carrageenan, and algin. This alga is also rich in magnesium, calcium, mineral, vitamins, and antioxidants. They are used in vitamin supplements.
6. Phaeophyta (Brown Algae)
Brown algae belong to the Phaeophyceae class and are among the largest species. A wide variety of kelp and seaweed found in the marine environment are a part of Phaeophyta. The brown color of the algae is derived from the pigment Fucoxanthin.
There are around 1500 identified species of brown algae, out of which mostly are commonly found in the colder oceans of the world. The food reserves of brown algae are complex carbohydrate polymers known as laminarin. Brown algae are the most complex in comparison to red and green algae. It contains chlorophyll A and C.
Some varieties of seaweed and kelp are a part of Phaeophyta. Rockweed, sargassum weed, and gain kelp are a few examples of brow algae.
Uses of Phaeophyta:
Brown algae are a nutritious food source for herbivorous organisms and humans. They have antibacterial, antirheumatic, antioxidant, and anticoagulant properties.
They are found on the coast of China, Japan, and Korea. Commercially brown algae are used in the production of alginates. Alginates are used in the food industry as fillers, additives, and thickeners. They are used for various conditions ranging from fibromyalgia, stress, weight loss, high cholesterol, and heart disease to cancer. Brown algae are also utilized as stabilizers in the battery ionization process.
7. Xanthophyta (Yellow-Green Algae)
Yellow-green algae are mostly freshwater algae, with some exceptions living in soil and marine habitats. Xanthophyte contains photosynthetic pigments chlorophyll A and C. Xanthophyte don’t contain the pigment fucoxanthin like other heterokonts; this is why they are lighter in color.
Their cell walls are made of hemicellulose and cellulose. They contain one to two flagella for motion. The cells of yellow-green algae are eukaryotic and contain silica and pectin in the cell wall. They most commonly reproduce asexually by nonmotile resting aplanospores or motile zoospores.
There are the least productive species of algae, with only 450 to 650 species of xanthophyte identified. They are closely related to green algae and were earlier classified as green algae based on the similarities.
Uses of Xanthophyta:
Haptophytes and Heterokonts are essential primary producers in aquatic habitats. They are also the primary carbon source for petroleum products like natural gas and crude oil.
8. Cyanobacteria (Blue-Green Algae)
Cyanobacteria or blue-green algae are photosynthetic gram-negative bacteria and are usually excluded from algae classification. They can be single-celled or colonial that may form sheets, filaments, or hollow balls. Cyanobacteria are commonly known as blue-green algae, but different species can occur in red, yellow, or brown colors.
The majority of blue-green algae contain chlorophyll a, in combination with various proteins known as phycobilins. This phycobilin gives the algae its typical blue-green or greyish-brown color. Cyanobacteria trap the sun’s energy and carry photosynthesis using chlorophyll pigment, unlike other bacteria. In some species, they have chlorophyll a, blue pigment phycobilin, yellowish carotenoids, and red pigment phycoerythrin.
Cyanobacteria can be found in almost all inhospitable environments, such as freshwater, oceans, soil, and bare rock. They are also most common among the different types of pond algae.
Nitrogen-fixing cyanobacteria can convert nitrogen gas (which can’t be absorbed by plants) into ammonia, nitrites, and nitrates (which plants can absorb). They require only carbon dioxide and nitrogen to live. Mostly the nitrogen fixers are the filamentous species as they contain specialized cells called heterocysts for the purpose.
These eukaryotic algae can survive in extreme environments such as hyper-saline water, hot springs, arid deserts, or freezing environments.
Cyanobacteria spirulina has been used as a functional food in parts of Mexico and Africa. Spirulina is rich in proteins, vitamins, and minerals. It’s widely used due to its antibacterial, antiviral, antiparasitic, and anticancer properties. The positive effects of spirulina for allergic rhinitis have been clinically proven. Besides this, spirulina fish food is popular as spirulina is rich in protein and is said to increase a more uniform growth rate for fish.
Uses of Cyanobacteria:
Cyanobacteria are used in wastewater treatment, aquaculture, fertilizers, and food. They are also used to produce secondary metabolites such as enzymes, vitamins, exopolysaccharides, pharmaceuticals, and toxins.
Farming of cyanobacteria is considered an environment-friendly sustainable practice. This is because cyanobacteria can produce biomass of very high value just by using water, nutrients, and C02. This also decreases greenhouse gas i.e., carbon dioxide. The biomass can be used further to produce energy, food, or biofertilizers.
Spirulina is the most commercially utilized species of blue-green algae. Spirulina supplements are popular because algae are rich in proteins, vitamins, carotenoids, minerals, and antioxidants. Spirulina is also used to reduce blood pressure and diabetes and manage cholesterol levels. The other health benefits associated with spirulina are blood sugar control, liver health, metabolic syndrome, obesity, antioxidant capacity, and even cancer prevention.
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Frequently Asked Questions About Algae
Is Algae a Plant?
No, algae aren’t classified as plants. They are considered plant-like because of the presence of chloroplasts and their ability to conduct photosynthesis. Apart from this, algae lack other structures that characterize true land plants, such as roots, leaves, stems, etc.
Algae are classified as microalgae and macroalgae, depending on their size. Further, there are several different types of algae, such as Red (Rhodophyta), Green (Chlorophyta), and Brown (Phaeophyta) algae.
Plants come under the kingdom Plantae on the other hand, algae are primitive organisms that belong to the Protista kingdom. However, it’s believed that true land plants share an evolutionary history with stoneworts, a branch of green algae.
Can You Eat Algae?
Yes, you can eat some types of algae. In fact, algae-based food supplements are already available in the form of spirulina capsules and tablets and spirulina powder for smoothies. Spirulina and chlorella are the types of algae that are the most nutritious and safe to be consumed by most.
However, there are some types of algae that are toxin and non-edible. The environment in which algae grows is also an important factor in determining whether it can be consumed or not. Freshwater algae are mostly toxic, whereas marine algae like seaweed are edible. Only algae harvested in clean waters with no contaminants, environmental pollutants, or metals should be considered for consumption.
Luckily, most edible algae are present in dietary supplement forms some are also consumed in raw forms, such as certain seaweeds. Algae is highly nutritious and sometimes contains more iron than spinach and more proteins than steak. But note that if you’re considering consuming them as a supplement, do look out for third-party testing and NSF certification for safety.
Is Spirulina an Algae Powder?
Yes, spirulina is an algae powder. Spirulina is a type of Cyanobacteria (blue-green algae) that is rich in vitamins, proteins, antioxidants, minerals, and carotenoids. Spirulina grows in both freshwater and saltwater and has many health benefits. Studies have suggested that spirulina can reduce inflammation, controls cholesterol levels, promotes healthy aging, and even have anti-cancer properties.
Here is the list of organic spirulina powder.
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What Is Spirulina Algae Good For?
Spirulina algae are good for:
- Eye Health
- Oral Health
- Weight Loss
- Preventing Cancer
- Boosting Metabolism
- Improving Gut Health
- Dealing with Diabetes
- Preventing Heart Disease
- Reducing Blood Pressure
- Managing Glucose Levels
- Managing Allergic Rhinitis
- Supporting Mental Health
- Lowering Cholesterol Levels
Here is the best spirulina supplement for anemia.
Algae are the most commonly found protists in the aquatic environment that resemble the characteristics of plants. Different types of algae possess different characteristics, but almost all can conduct photosynthesis. Based on the environment they have grown in and other factors, some algae have several health benefits, while some are toxic.
Especially species of algae like chlorella and spirulina are gaining widespread attention as dietary supplements due to their myriads of health benefits. But it’s important to note that more research is needed to conclude the benefits of algae over health. Therefore, if you’re considering to start taking any algae supplement, you’re advised to consult your healthcare provider beforehand.