Difference Between Blue Green Algae and Green Algae

The key difference between blue green algae and green algae is that blue green algae are prokaryotic organisms that belong to Kingdom Monera while green algae are eukaryotic organisms that belong to Kingdom Protista.

Photosynthesis is the process shown by photoautotrophs. It is the process that synthesizes carbohydrates (foods) by capturing energy from sunlight. The process requires the presence of photosynthetic pigments, CO₂ and water. Photoautotrophs possess photosynthetic pigments to carry out photosynthesis. There are three major groups of photoautotrophs as plants, cyanobacteria (blue green algae) and algae (including green algae). Therefore, both blue green algae and green algae are photosynthetic organisms. However, blue green algae are prokaryotic organisms while green algae are eukaryotic organisms. Accordingly, there is a difference between blue green algae and green algae based on their cellular organization and other characteristics.

CONTENTS

1. Overview and Key Difference
2. What is Blue Green Algae 
3. What is Green Algae
4. Similarities Between Blue Green Algae and Green Algae
5. Side by Side Comparison – Blue Green Algae vs Green Algae in Tabular Form
6. Summary

What is Blue Green Algae?

Blue green alga is a synonym of cyanobacteria. They are the photosynthetic bacteria that possess photosynthetic pigments to capture sunlight and produce foods. Blue green algae include unicellular organisms as well as multicellular organisms. Moreover, their bodies can be spherical, filamentous or sheet-like colonies. They can be found in moist soil, freshwater, and marine water. They appear in bluish green colour.

One special characteristic of blue green algae is their ability to fix atmospheric nitrogen. In order to fix atmospheric nitrogen, they possess special structures called heterocyst. Anabaena and Nostoc are two blue green algae that contain heterocyst to fix nitrogen. Some blue green algae form symbiotic relationships with plant roots. Microcystis, Anabaena, Nostoc, Oscillatoria, Tolypothrix, and Spirulina are some examples of blue green algae.

What are Green Algae?

Green algae are one of the five groups of algae found mostly in fresh water. Few green algal species are present in marine water and moist soils. They can be unicellular or multicellular. However, they are eukaryotic organisms. Moreover, they are photosynthetic organisms that possess chloroplasts and photosynthetic pigments such as chlorophyll a and b, carotene and xanthophylls.

It is believed that land plants have evolved from green algae since green algae and land plants possess several similar characteristics such as having double membranous chloroplasts and chlorophyll a and b as photosynthetic pigments, cellulose cell walls, starch as the major storage product, etc. Chlamydomonas, Chlorella, Pediastrum, Netrium, Hydrodictyon, Acetabularia, Ulva and Spirogyra are several species of green algae. In addition, some green algae form a symbiotic association with fungi and form lichens, which are ecologically important.

What are the Similarities Between Blue Green Algae and Green Algae?

• Both blue green algae and green algae include unicellular and multicellular organisms.
• Also, both live mostly in aquatic environments, but both can live on land in moist soils.
• Furthermore, both types are photosynthetic organisms.
• Besides, both can build up symbiotic relationships with other organisms.

What is the Difference Between Blue Green Algae and Green Algae?

Blue green algae are a group of prokaryotic organisms. Whereas, green algae are a group of eukaryotic organisms. So, we can consider this as the key difference between blue green algae and green algae. Furthermore, a significant difference between blue green algae and green algae is that the blue green algae do not possess chloroplasts, and other membrane-bound organelles while green algae possess chloroplasts and membrane-bound organelles.

Moreover, blue green algae have a special ability to fix nitrogen while green algae are unable to fix nitrogen. This is also a difference between blue green algae and green algae. Microcystis, Anabaena, Nostoc, Oscillatoria, Tolypothrix, and Spirulina are some examples of blue green algae while Chlamydomonas, Chlorella, Pediastrum, Netrium, Hydrodictyon, Acetabularia, Ulva and Spirogyra are some examples of green algae.

The following infographic summarizes the difference between blue green algae and green algae.

Summary – Blue Green Algae vs Green Algae

Blue green algae and green algae are two groups that include photosynthetic organisms. However, blue green algae are prokaryotic bacteria while green algae are eukaryotic protists. Thus, this is the key difference between blue green algae and green algae. Moreover, unlike green algae, blue green algae do not possess a nucleus, membrane-bound organelles, especially chloroplasts. However, blue green algae can fix atmospheric nitrogen, unlike green algae. Thus, this is a summary of the difference between blue green algae and green algae.

Reference:

1. “Green Alga.” Green Alga – an Overview | ScienceDirect Topics, Available here.
2. “Cyanobacteria.” Wikipedia, Wikimedia Foundation, 12 Mar. 2019, Available here.

Image Courtesy:

1. “Image-Anabaena sperica” By Original uploader was Patrioter6 at en.wikibooks – Transferred from en.wikibooks; transferred to Commons by User: Adrignola using CommonsHelper (CC BY-SA 3.0) via Commons Wikimedia
2. “SPIROGYRA” By fickleandfreckled (CC BY 2.0) via Flickr