Anabaena

Definition

Anabaena is a genus of filamentous, nitrogen-fixing, photosynthetic cyanobacteria that are commonly found in freshwater environments. These bacteria are classified as Gram-negative and are considered phototrophic, meaning they can use light energy to produce organic compounds through photosynthesis.

5 Must Know Facts For Your Next Test

1. Anabaena is capable of fixing atmospheric nitrogen, which allows it to thrive in environments with limited nitrogen availability.
2. The filamentous structure of Anabaena cells allows them to form specialized cells called heterocysts, which are responsible for nitrogen fixation.
3. Anabaena can produce toxic compounds called cyanotoxins, which can pose a threat to aquatic ecosystems and human health if the bacteria proliferate in water bodies.
4. Some species of Anabaena are able to form akinetes, which are thick-walled, dormant cells that can survive unfavorable environmental conditions.
5. Anabaena is commonly found in freshwater lakes, ponds, and slow-moving rivers, where it can form dense blooms that can disrupt aquatic ecosystems.

Review Questions

• Explain the significance of Anabaena's ability to fix atmospheric nitrogen.
  • Anabaena's ability to fix atmospheric nitrogen is a crucial adaptation that allows it to thrive in environments with limited nitrogen availability. By converting atmospheric nitrogen into ammonia or other organic compounds, Anabaena can provide a source of nitrogen for itself and other organisms in the ecosystem. This nitrogen-fixing capability makes Anabaena an important primary producer in freshwater environments, contributing to the overall productivity and nutrient cycling of the system.
• Describe the role of heterocysts in the physiology of Anabaena.
  • Anabaena cells can differentiate into specialized cells called heterocysts, which are responsible for nitrogen fixation. Heterocysts lack the ability to perform oxygenic photosynthesis, but they contain the necessary enzymes and machinery to convert atmospheric nitrogen into ammonia. This division of labor between the photosynthetic vegetative cells and the nitrogen-fixing heterocysts allows Anabaena to efficiently utilize both light energy and atmospheric nitrogen, making it a successful colonizer of nutrient-poor environments.
• Analyze the potential ecological and public health concerns associated with Anabaena blooms.
  • The proliferation of Anabaena in water bodies can lead to the formation of dense blooms, which can have significant ecological and public health implications. Anabaena can produce cyanotoxins, which are harmful compounds that can negatively impact aquatic organisms and pose a risk to human health if the contaminated water is used for drinking, recreation, or irrigation. Additionally, the presence of Anabaena blooms can disrupt the delicate balance of aquatic ecosystems, leading to changes in species composition, reduced biodiversity, and disruptions to nutrient cycling. Monitoring and managing Anabaena blooms is crucial for maintaining the health and integrity of freshwater environments.

Related terms

Cyanobacteria:

Cyanobacteria, also known as blue-green algae, are a group of bacteria that can perform oxygenic photosynthesis, similar to plants.

Nitrogen Fixation:

The process by which atmospheric nitrogen is converted into ammonia or other organic compounds, making it available for living organisms to use.

Phototroph: An organism that can use light energy to produce organic compounds through photosynthesis, such as cyanobacteria and some bacteria.