Cyanobacteria

Definition

Cyanobacteria are a group of photosynthetic bacteria, often referred to as blue-green algae, that can perform nitrogen fixation. They are crucial for ecosystems as they contribute to nutrient cycling and have symbiotic relationships with various plants and organisms.

5 Must Know Facts For Your Next Test

1. Cyanobacteria are one of the oldest living organisms on Earth, with a fossil record dating back over 3.5 billion years.
2. They play a significant role in aquatic ecosystems by producing oxygen through photosynthesis and serving as a food source for many organisms.
3. Certain cyanobacteria can form symbiotic relationships with plants, such as in the case of cycads and some ferns, helping them to access nitrogen from the atmosphere.
4. Cyanobacteria can thrive in various environments, including extreme conditions like hot springs and salt flats, showcasing their adaptability.
5. Some species of cyanobacteria can produce toxins that may be harmful to aquatic life and humans, leading to issues in water quality.

Review Questions

• How do cyanobacteria contribute to nitrogen fixation and what role do they play in ecosystems?
  • Cyanobacteria are key players in nitrogen fixation, converting atmospheric nitrogen into forms that can be used by plants. This process enriches soil fertility and supports plant growth, particularly in nutrient-poor environments. Their ability to fix nitrogen not only helps individual plants thrive but also enhances the overall health of ecosystems by promoting biodiversity and productivity.
• Discuss the significance of the symbiotic relationships formed between cyanobacteria and other organisms.
  • Symbiotic relationships involving cyanobacteria are significant for nutrient cycling and ecosystem stability. For example, cyanobacteria engage in mutualistic interactions with certain plants, providing them with essential nitrogen while receiving carbohydrates in return. These partnerships enhance the growth of host plants and contribute to the resilience of ecosystems by fostering diverse plant communities.
• Evaluate the impact of environmental factors on the distribution and ecological role of cyanobacteria.
  • Environmental factors such as temperature, light availability, and nutrient levels significantly influence the distribution and ecological roles of cyanobacteria. They thrive in a variety of conditions, from freshwater to saline environments. Changes in these factors can lead to harmful algal blooms, which disrupt aquatic ecosystems and water quality. Understanding these impacts helps inform strategies for managing ecosystems affected by cyanobacterial proliferation.

Related terms

Nitrogen Fixation: The process by which certain bacteria convert atmospheric nitrogen into ammonia, making it available for use by plants.

Symbiosis:

A close and often long-term interaction between two different biological species, which can be mutualistic, commensal, or parasitic.

Chlorophyll: The green pigment found in cyanobacteria and plants that is essential for photosynthesis, allowing the absorption of light energy.