Describe the main features of the environment occupied by Cyanobacteria including those that are from stromatolites.

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By Samantha Johnson

Biology Part A: 

By Samantha Johnson 424

1. Describe the main features of the environment occupied by Cyanobacteria including those that are from stromatolites.

Cyanobacteria can be found in just about every imaginable environment on earth.  Their primary inhabitations however are in wet or damp conditions, for example wet rocks, ponds, rainforests, streams and soil. They grow in water that is salty, salted or fresh and in cold or hot springs where no other micro algae can exist.

Most marine forms of cyanobacteria grow along the shore where the washed up sea weed and other material sit (the zone between low and high tide) to obtain their nutrients.  Cyanobacteria are also well-known for existing in freshwater localities with various trophic states. For example in Eutrophic lakes where water is murky and contains lots of plants to Oligotrophic lakes where water is very low in nutrients, which means that few algae grow there. This water is very clear. They have even been found on the fur of polar bears, giving them their greenish tinge.

Other colonies of cyanobacteria live on wet rocks or sediments, sometimes forming what appears to look like mats over these rocks which survive there for millions of years. These are stromatolites.   It is believed that cyanobacteria have been around for millions of years. Scientist have discovered that stromatolites are cyanobacteria in fossils that are extremely old (approximately 3 billion years old).

Cyanobacteria have no one habitat around the world because you can almost find them everywhere.

2. Identify and explain the role of Cyanobacteria in its ecosystem.

Cyanobacteria have been of  such tremendous importance in shaping the course of evolution and ecological change throughout the earth’s history. The air that we breathe (the oxygen) was generated by numerous cyanobacteria millions of years ago. Before this the atmosphere was full of numerous chemicals and would not be fit for human survival today.

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Cyanobacteria photosynthesise like plants.  They are the most important producers of the food chain in their ecosystem. Cyanobacteria in the ocean produce large amounts of oxygen hence their major roles as primary producers. Another great contribution of the cyanobacteria is the beginning of plant forms.

They play a great role in the chloroplasts of plants as the chloroplast is actually a cyanobacterium living within the plant’s cells. The cyanobacterium makes food for the eukaryote host in return for a home. Because they are photosynthetic and aquatic, cyanobacteria are often named to as the “blue-green algae.”


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