Cyanobacteria

Definition

Cyanobacteria are a phylum of bacteria that obtain their energy through photosynthesis. They are often referred to as 'blue-green algae' and can be found in a variety of aquatic environments, including freshwater and marine ecosystems.

5 Must Know Facts For Your Next Test

1. Cyanobacteria were among the first organisms to perform oxygenic photosynthesis, significantly contributing to Earth's oxygen atmosphere.
2. They can form harmful algal blooms (HABs) in water bodies, which can produce toxins affecting both aquatic life and human health.
3. Cyanobacteria have specialized cells called heterocysts that aid in nitrogen fixation under aerobic conditions.
4. These microorganisms have a symbiotic relationship with certain plants, such as ferns and cycads, providing them with essential nutrients.
5. Fossil evidence suggests that cyanobacteria have existed for approximately 3.5 billion years, making them some of the oldest known life forms on Earth.

Review Questions

• What role did cyanobacteria play in the development of Earth's early atmosphere?
• How do cyanobacteria contribute to harmful algal blooms (HABs) and what impact do these blooms have?
• What is the function of heterocysts in cyanobacteria?

Related terms

Photosynthesis: The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll pigments.

Nitrogen Fixation: The process by which certain microorganisms convert atmospheric nitrogen into a form usable by plants.

Algae:

Simple non-flowering plants typically found in water, they include seaweeds and many single-celled forms like diatoms.