Cyanobacteria

Definition

Cyanobacteria are a diverse group of photosynthetic bacteria known for their ability to perform oxygenic photosynthesis, contributing significantly to the Earth's oxygen production. These microorganisms play critical roles in various ecosystems, influencing biogeochemical cycles and shaping geological processes through their interactions with other organisms and environmental factors.

5 Must Know Facts For Your Next Test

1. Cyanobacteria are among the oldest known living organisms, with fossil evidence dating back over 3.5 billion years.
2. These bacteria are capable of thriving in extreme environments, such as hot springs and salt flats, showcasing their ecological versatility.
3. Cyanobacteria can form biofilms, which are dense clusters of microbial cells that adhere to surfaces and play significant roles in nutrient cycling and ecosystem stability.
4. They are important contributors to the nitrogen cycle due to their ability to fix atmospheric nitrogen, thus supporting plant growth in nutrient-poor environments.
5. Cyanobacteria have been instrumental in the formation of microbialites and stromatolites, which provide insights into ancient ecosystems and the history of life on Earth.

Review Questions

• How do cyanobacteria contribute to the biogeochemical cycles in various environments?
  • Cyanobacteria play a crucial role in biogeochemical cycles through their ability to perform oxygenic photosynthesis and fix nitrogen. By converting sunlight into energy and producing oxygen, they contribute significantly to the primary production in aquatic ecosystems. Additionally, their nitrogen-fixing capabilities enhance nutrient availability in both terrestrial and aquatic habitats, supporting a wide range of organisms and promoting ecosystem health.
• Discuss the significance of biofilms formed by cyanobacteria in geological processes.
  • Biofilms formed by cyanobacteria are essential in geological processes as they influence sediment stabilization and nutrient cycling. These microbial mats trap sediments, contributing to the formation of structures like stromatolites over time. Furthermore, they create microenvironments that facilitate chemical reactions essential for mineral precipitation, helping shape the geological features of their habitats.
• Evaluate the role of cyanobacteria in ancient ecosystems as evidenced by their contribution to microbialites and stromatolites.
  • Cyanobacteria were pivotal in shaping ancient ecosystems through their formation of microbialites and stromatolites. These structures serve as vital records of early life on Earth and demonstrate how cyanobacteria could create stable environments for other organisms. Their ability to trap sediments and promote mineralization highlights their ecological significance and provides insights into the conditions of early Earth, including atmospheric composition and the evolution of life forms.

Related terms

Oxygenic Photosynthesis: A process by which certain organisms, including cyanobacteria, convert light energy into chemical energy while producing oxygen as a byproduct.

Nitrogen Fixation: The conversion of atmospheric nitrogen into ammonia or related compounds, a process carried out by some cyanobacteria, which enriches nutrient availability in aquatic and terrestrial environments.

Stromatolites:

Layered structures formed by the activity of microbial communities, particularly cyanobacteria, which trap sediments and are considered some of the oldest evidence of life on Earth.